vm.c

#include <assert.h>
#include <limits.h>
#include <stdarg.h>
#include <string.h>
#include <errno.h>
#include <sys/stat.h>
 
#include <kuroko/vm.h>
#include <kuroko/debug.h>
#include <kuroko/memory.h>
#include <kuroko/compiler.h>
#include <kuroko/object.h>
#include <kuroko/table.h>
#include <kuroko/util.h>
 
#include "private.h"
#include "opcode_enum.h"
 
/* Ensure we don't have a macro for this so we can reference a local version. */
#undef krk_currentThread
 
/* This is macro'd to krk_vm for namespacing reasons. */
KrkVM vm = {0};
 
#ifndef KRK_DISABLE_THREADS
/*
 * Marking our little VM thread state as 'initial-exec' is
 * the fastest way to allocate TLS data and yields virtually
 * identical performance in the single-thread case to not
 * having a TLS pointer, but it has some drawbacks...
 *
 * Despite documentation saying otherwise, a small thread-local
 * can generally be allocated even with dlopen, but this is
 * not guaranteed.
 */
__attribute__((tls_model("initial-exec")))
__thread KrkThreadState krk_currentThread;
#else
/* There is only one thread, so don't store it as TLS... */
KrkThreadState krk_currentThread;
#endif
 
#if !defined(KRK_DISABLE_THREADS) && defined(__APPLE__) && defined(__aarch64__)
void krk_forceThreadData(void) {
    krk_currentThread.next = NULL;
    assert(&krk_currentThread == _macos_currentThread());
}
#define krk_currentThread (*_macos_currentThread())
#endif
 
/*
 * In some threading configurations, particular on Windows,
 * we can't have executables reference our thread-local thread
 * state object directly; in order to provide a consistent API
 * we make @ref krk_currentThread a macro outside of the core
 * sources that will call this function.
 */
KrkThreadState * krk_getCurrentThread(void) {
    return &krk_currentThread;
}
 
void krk_resetStack(void) {
    krk_currentThread.stackTop = krk_currentThread.stack;
    krk_currentThread.stackMax = krk_currentThread.stack + krk_currentThread.stackSize;
    krk_currentThread.frameCount = 0;
    krk_currentThread.openUpvalues = NULL;
    krk_currentThread.flags &= ~KRK_THREAD_HAS_EXCEPTION;
    krk_currentThread.currentException = NONE_VAL();
}
 
void krk_growStack(void) {
    size_t old = krk_currentThread.stackSize;
    size_t old_offset = krk_currentThread.stackTop - krk_currentThread.stack;
    size_t newsize = KRK_GROW_CAPACITY(old);
    if (krk_currentThread.flags & KRK_THREAD_DEFER_STACK_FREE) {
        KrkValue * newStack = KRK_GROW_ARRAY(KrkValue, NULL, 0, newsize);
        memcpy(newStack, krk_currentThread.stack, sizeof(KrkValue) * old);
        krk_currentThread.stack = newStack;
        krk_currentThread.flags &= ~(KRK_THREAD_DEFER_STACK_FREE);
    } else {
        krk_currentThread.stack = KRK_GROW_ARRAY(KrkValue, krk_currentThread.stack, old, newsize);
    }
    krk_currentThread.stackSize = newsize;
    krk_currentThread.stackTop = krk_currentThread.stack + old_offset;
    krk_currentThread.stackMax = krk_currentThread.stack + krk_currentThread.stackSize;
}
 
inline void krk_push(KrkValue value) {
    if (unlikely(krk_currentThread.stackTop == krk_currentThread.stackMax)) krk_growStack();
    *krk_currentThread.stackTop++ = value;
}
 
inline KrkValue krk_pop(void) {
    if (unlikely(krk_currentThread.stackTop == krk_currentThread.stack)) {
        abort();
    }
    return *--krk_currentThread.stackTop;
}
 
/* Read a value `distance` units from the top of the stack without poping it. */
inline KrkValue krk_peek(int distance) {
    return krk_currentThread.stackTop[-1 - distance];
}
 
/* Exchange the value `distance` units down from the top of the stack with
 * the value at the top of the stack. */
inline void krk_swap(int distance) {
    KrkValue top = krk_currentThread.stackTop[-1];
    krk_currentThread.stackTop[-1] = krk_currentThread.stackTop[-1 - distance];
    krk_currentThread.stackTop[-1 - distance] = top;
}
 
KrkNative * krk_defineNative(KrkTable * table, const char * name, NativeFn function) {
    KrkNative * func = krk_newNative(function, name, 0);
    krk_attachNamedObject(table, name, (KrkObj*)func);
    return func;
}
 
KrkClass * krk_makeClass(KrkInstance * module, KrkClass ** _class, const char * name, KrkClass * base) {
    KrkString * str_Name = krk_copyString(name,strlen(name));
    krk_push(OBJECT_VAL(str_Name));
    *_class = krk_newClass(str_Name, base);
    if (module) {
        krk_push(OBJECT_VAL(*_class));
        /* Bind it */
        krk_attachNamedObject(&module->fields,name,(KrkObj*)*_class);
        /* Now give it a __module__ */
        KrkValue moduleName = NONE_VAL();
        krk_tableGet(&module->fields, OBJECT_VAL(S("__name__")), &moduleName);
        krk_attachNamedValue(&(*_class)->methods,"__module__",moduleName);
        krk_pop();
    }
    krk_pop();
    return *_class;
}
 
_nonnull
void krk_finalizeClass(KrkClass * _class) {
    KrkValue tmp;
 
    struct TypeMap {
        KrkObj ** method;
        KrkSpecialMethods index;
    };
    struct TypeMap specials[] = {
    #define CACHED_METHOD(a,b,c) {&_class-> c, METHOD_ ## a},
    #define SPECIAL_ATTRS(a,b)
    #include "methods.h"
    #undef CACHED_METHOD
    #undef SPECIAL_ATTRS
        {NULL, 0},
    };
 
    _class->cacheIndex = 0;
 
    for (struct TypeMap * entry = specials; entry->method; ++entry) {
        *entry->method = NULL;
        KrkClass * _base = _class;
        while (_base) {
            if (krk_tableGet_fast(&_base->methods, AS_STRING(vm.specialMethodNames[entry->index]), &tmp)) break;
            _base = _base->base;
        }
        if (_base && (IS_CLOSURE(tmp) || IS_NATIVE(tmp)) && (!(AS_OBJECT(tmp)->flags & KRK_OBJ_FLAGS_FUNCTION_IS_STATIC_METHOD) || entry->index == METHOD_NEW)) {
            *entry->method = AS_OBJECT(tmp);
        }
    }
 
    if (_class->base && _class->_eq != _class->base->_eq) {
        if (_class->_hash == _class->base->_hash) {
            _class->_hash = NULL;
            KrkValue v;
            if (!krk_tableGet_fast(&_class->methods, AS_STRING(vm.specialMethodNames[METHOD_HASH]), &v)) {
                krk_tableSet(&_class->methods, vm.specialMethodNames[METHOD_HASH], NONE_VAL());
            }
        }
    }
 
    for (size_t i = 0; i < _class->subclasses.capacity; ++i) {
        KrkTableEntry * entry = &_class->subclasses.entries[i];
        if (IS_KWARGS(entry->key)) continue;
        krk_finalizeClass(AS_CLASS(entry->key));
    }
}
 
inline KrkClass * krk_getType(KrkValue of) {
 
    static size_t objClasses[] = {
        [KRK_OBJ_CODEOBJECT]   = offsetof(struct BaseClasses, codeobjectClass),
        [KRK_OBJ_NATIVE]       = offsetof(struct BaseClasses, functionClass),
        [KRK_OBJ_CLOSURE]      = offsetof(struct BaseClasses, functionClass),
        [KRK_OBJ_BOUND_METHOD] = offsetof(struct BaseClasses, methodClass),
        [KRK_OBJ_STRING]       = offsetof(struct BaseClasses, strClass),
        [KRK_OBJ_UPVALUE]      = offsetof(struct BaseClasses, CellClass),
        [KRK_OBJ_CLASS]        = offsetof(struct BaseClasses, typeClass),
        [KRK_OBJ_TUPLE]        = offsetof(struct BaseClasses, tupleClass),
        [KRK_OBJ_BYTES]        = offsetof(struct BaseClasses, bytesClass),
        [KRK_OBJ_INSTANCE]     = 0,
    };
 
    switch (KRK_VAL_TYPE(of)) {
        case KRK_VAL_INTEGER:
            return vm.baseClasses->intClass;
        case KRK_VAL_BOOLEAN:
            return vm.baseClasses->boolClass;
        case KRK_VAL_NONE:
            return vm.baseClasses->noneTypeClass;
        case KRK_VAL_NOTIMPL:
            return vm.baseClasses->notImplClass;
        case KRK_VAL_OBJECT:
            if (IS_INSTANCE(of)) return AS_INSTANCE(of)->_class;
            if (IS_CLASS(of) && AS_CLASS(of)->_class) return AS_CLASS(of)->_class;
            return *(KrkClass **)((char*)vm.baseClasses + objClasses[AS_OBJECT(of)->type]);
        default:
            if (IS_FLOATING(of)) return vm.baseClasses->floatClass;
            return vm.baseClasses->objectClass;
    }
}
 
int krk_isInstanceOf(KrkValue obj, const KrkClass * type) {
    KrkClass * mine = krk_getType(obj);
    while (mine) {
        if (mine == type) return 1;
        mine = mine->base;
    }
    return 0;
}
 
static inline int checkArgumentCount(const KrkClosure * closure, int argCount) {
    int minArgs = closure->function->requiredArgs;
    int maxArgs = closure->function->potentialPositionals;
    if (unlikely(argCount < minArgs || argCount > maxArgs)) {
        krk_runtimeError(vm.exceptions->argumentError, "%s() takes %s %d %sargument%s (%d given)",
        closure->function->name ? closure->function->name->chars : "<unnamed>",
        (minArgs == maxArgs) ? "exactly" : (argCount < minArgs ? "at least" : "at most"),
        (argCount < minArgs) ? minArgs : maxArgs,
        closure->function->keywordArgs ? "positional " : "",
        ((argCount < minArgs) ? minArgs : maxArgs) == 1 ? "" : "s",
        argCount);
        return 0;
    }
    return 1;
}
 
static void multipleDefs(const KrkClosure * closure, int destination) {
    krk_runtimeError(vm.exceptions->typeError, "%s() got multiple values for argument '%S'",
        closure->function->name ? closure->function->name->chars : "<unnamed>",
        (destination < closure->function->potentialPositionals ? AS_STRING(closure->function->positionalArgNames.values[destination]) :
            (destination - closure->function->potentialPositionals < closure->function->keywordArgs ? AS_STRING(closure->function->keywordArgNames.values[destination - closure->function->potentialPositionals]) :
                S("<unnamed>"))));
}
 
static int _unpack_op(void * context, const KrkValue * values, size_t count) {
    KrkTuple * output = context;
    if (unlikely(output->values.count + count > output->values.capacity)) {
        krk_runtimeError(vm.exceptions->valueError, "too many values to unpack (expected %zu)",
            output->values.capacity);
        return 1;
    }
    for (size_t i = 0; i < count; ++i) {
        output->values.values[output->values.count++] = values[i];
    }
    return 0;
}
 
static int _unpack_args(void * context, const KrkValue * values, size_t count) {
    KrkValueArray * positionals = context;
    if (positionals->count + count > positionals->capacity) {
        size_t old = positionals->capacity;
        positionals->capacity = (count == 1) ? KRK_GROW_CAPACITY(old) : (positionals->count + count);
        positionals->values = KRK_GROW_ARRAY(KrkValue, positionals->values, old, positionals->capacity);
    }
 
    for (size_t i = 0; i < count; ++i) {
        positionals->values[positionals->count++] = values[i];
    }
 
    return 0;
}
 
int krk_processComplexArguments(int argCount, KrkValueArray * positionals, KrkTable * keywords, const char * name) {
#define TOP_ARGS 3
    size_t kwargsCount = AS_INTEGER(krk_currentThread.stackTop[-TOP_ARGS]);
    argCount--;
 
    /* First, process all the positionals, including any from extractions. */
    size_t existingPositionalArgs = argCount - kwargsCount * 2;
    for (size_t i = 0; i < existingPositionalArgs; ++i) {
        krk_writeValueArray(positionals, krk_currentThread.stackTop[-argCount + i - TOP_ARGS]);
    }
 
    size_t startOfExtras = &krk_currentThread.stackTop[-kwargsCount * 2 - TOP_ARGS] - krk_currentThread.stack;
    /* Now unpack everything else. */
    for (size_t i = 0; i < kwargsCount; ++i) {
        KrkValue key = krk_currentThread.stack[startOfExtras + i*2];
        KrkValue value = krk_currentThread.stack[startOfExtras + i*2 + 1];
        if (IS_KWARGS(key)) {
            if (AS_INTEGER(key) == KWARGS_LIST) { /* unpack list */
                if (krk_unpackIterable(value,positionals,_unpack_args)) return 0;
            } else if (AS_INTEGER(key) == KWARGS_DICT) { /* unpack dict */
                if (!IS_dict(value)) {
                    krk_runtimeError(vm.exceptions->typeError, "%s(): **expression value is not a dict.", name);
                    return 0;
                }
                for (size_t i = 0; i < AS_DICT(value)->used; ++i) {
                    KrkTableEntry * entry = &AS_DICT(value)->entries[i];
                    if (!IS_KWARGS(entry->key)) {
                        if (!IS_STRING(entry->key)) {
                            krk_runtimeError(vm.exceptions->typeError, "%s(): **expression contains non-string key", name);
                            return 0;
                        }
                        if (!krk_tableSet(keywords, entry->key, entry->value)) {
                            krk_runtimeError(vm.exceptions->typeError, "%s() got multiple values for argument '%S'", name, AS_STRING(entry->key));
                            return 0;
                        }
                    }
                }
            } else if (AS_INTEGER(key) == KWARGS_SINGLE) { /* single value */
                krk_writeValueArray(positionals, value);
            }
        } else if (IS_STRING(key)) {
            if (!krk_tableSet(keywords, key, value)) {
                krk_runtimeError(vm.exceptions->typeError, "%s() got multiple values for argument '%S'", name, AS_STRING(key));
                return 0;
            }
        }
    }
    return 1;
}
 
static inline int _callManaged(KrkClosure * closure, int argCount, int returnDepth) {
    size_t potentialPositionalArgs = closure->function->potentialPositionals;
    size_t totalArguments = closure->function->totalArguments;
    size_t offsetOfExtraArgs = potentialPositionalArgs;
    size_t argCountX = argCount;
 
    if (argCount && unlikely(IS_KWARGS(krk_currentThread.stackTop[-1]))) {
 
        KrkValue myList = krk_list_of(0,NULL,0);
        krk_push(myList);
        KrkValueArray * positionals;
        positionals = AS_LIST(myList);
 
        KrkValue myDict = krk_dict_of(0,NULL,0);
        krk_push(myDict);
        KrkTable * keywords;
        keywords = AS_DICT(myDict);
 
        /* This processes the existing argument list into a ValueArray and a Table with the args and keywords */
        if (!krk_processComplexArguments(argCount, positionals, keywords, closure->function->name ? closure->function->name->chars : "<unnamed>")) return 0;
 
        /* Store scratch while we adjust; we can not make calls while using these scratch
         * registers as they may be clobbered by a nested call to _callManaged. */
        krk_currentThread.scratchSpace[0] = myList;
        krk_currentThread.scratchSpace[1] = myDict;
 
        /* Pop three things, including the kwargs count */
        krk_pop(); /* dict */
        krk_pop(); /* list */
        krk_pop(); /* kwargs */
 
        /* We popped the kwargs sentinel, which counted for one argCount */
        argCount--;
 
        /* Do we already know we have too many arguments? Let's bail before doing a bunch of work. */
        if ((positionals->count > potentialPositionalArgs) && !(closure->function->obj.flags & KRK_OBJ_FLAGS_CODEOBJECT_COLLECTS_ARGS)) {
            checkArgumentCount(closure,positionals->count);
            goto _errorDuringPositionals;
        }
 
        /* Prepare stack space for all potential positionals, mark them unset */
        for (size_t i = 0; i < (size_t)argCount; ++i) {
            krk_currentThread.stackTop[-argCount + i] = KWARGS_VAL(0);
        }
 
        /* Do we have a bunch of unused keyword argument slots? Fill them in. */
        while ((size_t)argCount < potentialPositionalArgs) {
            krk_push(KWARGS_VAL(0));
            argCount++;
        }
 
        /* Did we have way more arguments than we needed? Put the stack where it should be. */
        while ((size_t)argCount > potentialPositionalArgs) {
            krk_pop();
            argCount--;
        }
 
        /* Place positional arguments */
        for (size_t i = 0; i < potentialPositionalArgs && i < positionals->count; ++i) {
            krk_currentThread.stackTop[-argCount + i] = positionals->values[i];
        }
 
        if (closure->function->obj.flags & KRK_OBJ_FLAGS_CODEOBJECT_COLLECTS_ARGS) {
            size_t count  = (positionals->count > potentialPositionalArgs) ? (positionals->count - potentialPositionalArgs) : 0;
            KrkValue * offset = (count == 0) ? NULL : &positionals->values[potentialPositionalArgs];
            krk_push(krk_list_of(count, offset, 0));
            argCount++;
        }
 
        for (size_t i = 0; i < closure->function->keywordArgs; ++i) {
            krk_push(KWARGS_VAL(0));
            argCount++;
        }
 
        /* We're done with the positionals */
        krk_currentThread.scratchSpace[0] = NONE_VAL();
 
        /* Now place keyword arguments */
        for (size_t i = 0; i < keywords->used; ++i) {
            KrkTableEntry * entry = &keywords->entries[i];
            if (!IS_KWARGS(entry->key)) {
                KrkValue name = entry->key;
                KrkValue value = entry->value;
                /* See if we can place it */
                for (int j = 0; j < (int)closure->function->potentialPositionals; ++j) {
                    if (krk_valuesSame(name, closure->function->positionalArgNames.values[j])) {
                        if (!IS_KWARGS(krk_currentThread.stackTop[-argCount + j])) {
                            multipleDefs(closure,j);
                            goto _errorAfterPositionals;
                        }
                        krk_currentThread.stackTop[-argCount + j] = value;
                        goto _finishKwarg;
                    }
                }
                /* See if it's a keyword arg. */
                for (int j = 0; j < (int)closure->function->keywordArgs; ++j) {
                    if (krk_valuesSame(name, closure->function->keywordArgNames.values[j])) {
                        if (!IS_KWARGS(krk_currentThread.stackTop[-argCount + j + closure->function->potentialPositionals + !!(closure->function->obj.flags & KRK_OBJ_FLAGS_CODEOBJECT_COLLECTS_ARGS)])) {
                            multipleDefs(closure, j + closure->function->potentialPositionals);
                            goto _errorAfterPositionals;
                        }
                        krk_currentThread.stackTop[-argCount + j + closure->function->potentialPositionals + !!(closure->function->obj.flags & KRK_OBJ_FLAGS_CODEOBJECT_COLLECTS_ARGS)] = value;
                        goto _finishKwarg;
                    }
                }
                if (!(closure->function->obj.flags & KRK_OBJ_FLAGS_CODEOBJECT_COLLECTS_KWS)) {
                    krk_runtimeError(vm.exceptions->typeError, "%s() got an unexpected keyword argument '%S'",
                        closure->function->name ? closure->function->name->chars : "<unnamed>",
                        AS_STRING(name));
                    goto _errorAfterPositionals;
                }
                continue;
_finishKwarg:
                entry->key = KWARGS_VAL(0);
                entry->value = BOOLEAN_VAL(1);
                continue;
            }
        }
 
        /* If this function takes a **kwargs, we need to provide it as a dict */
        if (closure->function->obj.flags & KRK_OBJ_FLAGS_CODEOBJECT_COLLECTS_KWS) {
            krk_push(krk_dict_of(0,NULL,0));
            argCount++;
            krk_tableAddAll(keywords, AS_DICT(krk_peek(0)));
        }
 
        /* We're done with the keywords */
        krk_currentThread.scratchSpace[1] = NONE_VAL();
 
        for (size_t i = 0; i < (size_t)closure->function->requiredArgs; ++i) {
            if (IS_KWARGS(krk_currentThread.stackTop[-argCount + i])) {
                if (i < closure->function->localNameCount) {
                    krk_runtimeError(vm.exceptions->typeError, "%s() %s: '%S'",
                        closure->function->name ? closure->function->name->chars : "<unnamed>",
                        "missing required positional argument",
                        closure->function->localNames[i].name);
                } else {
                    krk_runtimeError(vm.exceptions->typeError, "%s() %s",
                        closure->function->name ? closure->function->name->chars : "<unnamed>",
                        "missing required positional argument");
                }
                goto _errorAfterKeywords;
            }
        }
 
        argCountX = argCount - closure->function->keywordArgs - (!!(closure->function->obj.flags & KRK_OBJ_FLAGS_CODEOBJECT_COLLECTS_ARGS) + !!(closure->function->obj.flags & KRK_OBJ_FLAGS_CODEOBJECT_COLLECTS_KWS));
    } else if ((size_t)argCount > potentialPositionalArgs && (closure->function->obj.flags & KRK_OBJ_FLAGS_CODEOBJECT_COLLECTS_ARGS)) {
        KrkValue * startOfPositionals = &krk_currentThread.stackTop[-argCount];
        KrkValue tmp = krk_callNativeOnStack(argCount - potentialPositionalArgs,
            &startOfPositionals[potentialPositionalArgs], 0, krk_list_of);
        startOfPositionals = &krk_currentThread.stackTop[-argCount];
        startOfPositionals[offsetOfExtraArgs] = tmp;
        argCount = potentialPositionalArgs + 1;
        argCountX = argCount - 1;
        while (krk_currentThread.stackTop > startOfPositionals + argCount) krk_pop();
    }
 
    if (unlikely(!checkArgumentCount(closure, argCountX))) goto _errorAfterKeywords;
 
    while (argCount < (int)totalArguments) {
        krk_push(KWARGS_VAL(0));
        argCount++;
    }
 
    if (unlikely(closure->function->obj.flags & (KRK_OBJ_FLAGS_CODEOBJECT_IS_GENERATOR | KRK_OBJ_FLAGS_CODEOBJECT_IS_COROUTINE))) {
        KrkInstance * gen = krk_buildGenerator(closure, krk_currentThread.stackTop - argCount, argCount);
        krk_currentThread.stackTop = krk_currentThread.stackTop - argCount - returnDepth;
        krk_push(OBJECT_VAL(gen));
        return 2;
    }
 
    if (unlikely(krk_currentThread.frameCount == (size_t)krk_currentThread.maximumCallDepth)) {
        krk_runtimeError(vm.exceptions->baseException, "maximum recursion depth exceeded");
        goto _errorAfterKeywords;
    }
 
    KrkCallFrame * frame = &krk_currentThread.frames[krk_currentThread.frameCount++];
    frame->closure = closure;
    frame->ip = closure->function->chunk.code;
    frame->slots = (krk_currentThread.stackTop - argCount) - krk_currentThread.stack;
    frame->outSlots = frame->slots - returnDepth;
    frame->globalsOwner = closure->globalsOwner;
    frame->globals = closure->globalsTable;
    return 1;
 
_errorDuringPositionals:
    krk_currentThread.scratchSpace[0] = NONE_VAL();
_errorAfterPositionals:
    krk_currentThread.scratchSpace[1] = NONE_VAL();
_errorAfterKeywords:
    return 0;
}
 
inline KrkValue krk_callNativeOnStack(size_t argCount, const KrkValue *stackArgs, int hasKw, NativeFn native) {
 
    if (unlikely(krk_currentThread.flags & KRK_THREAD_DEFER_STACK_FREE)) {
        return native(argCount, stackArgs, hasKw);
    }
 
    /* Mark the thread's stack as preserved. */
    krk_currentThread.flags |= KRK_THREAD_DEFER_STACK_FREE;
    size_t sizeBefore  = krk_currentThread.stackSize;
    void * stackBefore = krk_currentThread.stack;
    KrkValue result = native(argCount, stackArgs, hasKw);
 
    if (unlikely(krk_currentThread.stack != stackBefore)) {
        KRK_FREE_ARRAY(KrkValue, stackBefore, sizeBefore);
    }
 
    krk_currentThread.flags &= ~(KRK_THREAD_DEFER_STACK_FREE);
    return result;
}
 
static void _rotate(size_t argCount) {
    krk_push(NONE_VAL());
    memmove(&krk_currentThread.stackTop[-argCount],&krk_currentThread.stackTop[-argCount-1],sizeof(KrkValue) * argCount);
}
 
static inline int _callNative(KrkNative* callee, int argCount, int returnDepth) {
    NativeFn native = (NativeFn)callee->function;
    size_t stackOffsetAfterCall = (krk_currentThread.stackTop - krk_currentThread.stack) - argCount - returnDepth;
    KrkValue result;
    if (unlikely(argCount && IS_KWARGS(krk_currentThread.stackTop[-1]))) {
        /* Prep space for our list + dictionary */
        KrkValue myList = krk_list_of(0,NULL,0);
        krk_push(myList);
        KrkValue myDict = krk_dict_of(0,NULL,0);
        krk_push(myDict);
 
        /* Parse kwargs stuff into the list+dict; note, this no longer pops anything, and expects
         * our list + dict to be at the top: [kwargs] [list] [dict] */
        if (unlikely(!krk_processComplexArguments(argCount, AS_LIST(myList), AS_DICT(myDict), callee->name))) return 0;
 
        /* Write the dict into the list */
        krk_writeValueArray(AS_LIST(myList), myDict);
 
        /* Also add a list for storing references that get removed from the kwargs dict during mutation. */
        KrkValue refList = krk_list_of(0,NULL,0);
        krk_push(refList);
        krk_writeValueArray(AS_LIST(myList), refList);
 
        /* Reduce the stack to just the list */
        krk_currentThread.stack[stackOffsetAfterCall] = myList;
        krk_currentThread.stackTop = &krk_currentThread.stack[stackOffsetAfterCall+1];
 
        /* Call with list as arguments */
        result = native(AS_LIST(myList)->count-2, AS_LIST(myList)->values, 1);
    } else {
        result = krk_callNativeOnStack(argCount, krk_currentThread.stackTop - argCount, 0, native);
    }
    krk_currentThread.stackTop = &krk_currentThread.stack[stackOffsetAfterCall];
    krk_push(result);
    return 2;
}
 
int krk_callValue(KrkValue callee, int argCount, int returnDepth) {
    if (likely(IS_OBJECT(callee))) {
        _innerObject:
        switch (OBJECT_TYPE(callee)) {
            case KRK_OBJ_CLOSURE: return _callManaged(AS_CLOSURE(callee), argCount, returnDepth);
            case KRK_OBJ_NATIVE: return _callNative(AS_NATIVE(callee), argCount, returnDepth);
            case KRK_OBJ_BOUND_METHOD: {
                KrkBoundMethod * bound = AS_BOUND_METHOD(callee);
                if (unlikely(!bound->method)) {
                    krk_runtimeError(vm.exceptions->argumentError, "???");
                    return 0;
                }
                if (unlikely(returnDepth == 0)) _rotate(argCount);
                krk_currentThread.stackTop[-argCount - 1] = bound->receiver;
                callee = OBJECT_VAL(bound->method);
                argCount++;
                returnDepth = returnDepth ? (returnDepth - 1) : 0;
                goto _innerObject;
            }
            default: {
                KrkClass * _class = krk_getType(callee);
                if (likely(_class->_call != NULL)) {
                    if (unlikely(returnDepth == 0)) _rotate(argCount);
                    krk_currentThread.stackTop[-argCount - 1] = callee;
                    argCount++;
                    returnDepth = returnDepth ? (returnDepth - 1) : 0;
                    return (_class->_call->type == KRK_OBJ_CLOSURE) ? _callManaged((KrkClosure*)_class->_call, argCount, returnDepth) : _callNative((KrkNative*)_class->_call, argCount, returnDepth);
                } else {
                    krk_runtimeError(vm.exceptions->typeError, "'%T' object is not callable", callee);
                    return 0;
                }
            }
        }
    }
    krk_runtimeError(vm.exceptions->typeError, "'%T' object is not callable", callee);
    return 0;
}
 
KrkValue krk_callStack(int argCount) {
    switch (krk_callValue(krk_peek(argCount), argCount, 1)) {
        case 2: return krk_pop();
        case 1: return krk_runNext();
        default: return NONE_VAL();
    }
}
 
KrkValue krk_callDirect(KrkObj * callable, int argCount) {
    int result = 0;
    switch (callable->type) {
        case KRK_OBJ_CLOSURE: result = _callManaged((KrkClosure*)callable, argCount, 0); break;
        case KRK_OBJ_NATIVE: result = _callNative((KrkNative*)callable, argCount, 0); break;
        default: __builtin_unreachable();
    }
    if (likely(result == 2)) return krk_pop();
    else if (result == 1) return krk_runNext();
    return NONE_VAL();
}
 
static KrkUpvalue * captureUpvalue(int index) {
    KrkUpvalue * prevUpvalue = NULL;
    KrkUpvalue * upvalue = krk_currentThread.openUpvalues;
    while (upvalue != NULL && upvalue->location > index) {
        prevUpvalue = upvalue;
        upvalue = upvalue->next;
    }
    if (upvalue != NULL && upvalue->location == index) {
        return upvalue;
    }
    KrkUpvalue * createdUpvalue = krk_newUpvalue(index);
    createdUpvalue->next = upvalue;
    if (prevUpvalue == NULL) {
        krk_currentThread.openUpvalues = createdUpvalue;
    } else {
        prevUpvalue->next = createdUpvalue;
    }
    return createdUpvalue;
}
 
#define UPVALUE_LOCATION(upvalue) (upvalue->location == -1 ? &upvalue->closed : &upvalue->owner->stack[upvalue->location])
 
static void closeUpvalues(int last) {
    while (krk_currentThread.openUpvalues != NULL && krk_currentThread.openUpvalues->location >= last) {
        KrkUpvalue * upvalue = krk_currentThread.openUpvalues;
        upvalue->closed = krk_currentThread.stack[upvalue->location];
        upvalue->location = -1;
        krk_currentThread.openUpvalues = upvalue->next;
    }
}
 
void krk_attachNamedValue(KrkTable * table, const char name[], KrkValue obj) {
    krk_push(obj);
    krk_push(OBJECT_VAL(krk_copyString(name,strlen(name))));
    krk_tableSet(table, krk_peek(0), krk_peek(1));
    krk_pop();
    krk_pop();
}
 
void krk_attachNamedObject(KrkTable * table, const char name[], KrkObj * obj) {
    krk_attachNamedValue(table,name,OBJECT_VAL(obj));
}
 
int krk_isFalsey(KrkValue value) {
    switch (KRK_VAL_TYPE(value)) {
        case KRK_VAL_NONE: return 1;
        case KRK_VAL_BOOLEAN: return !AS_BOOLEAN(value);
        case KRK_VAL_INTEGER: return !AS_INTEGER(value);
        case KRK_VAL_NOTIMPL: return 1;
        case KRK_VAL_OBJECT: {
            switch (AS_OBJECT(value)->type) {
                case KRK_OBJ_STRING: return !AS_STRING(value)->codesLength;
                case KRK_OBJ_TUPLE: return !AS_TUPLE(value)->values.count;
                default: break;
            }
            break;
        }
        default:
#ifndef KRK_NO_FLOAT
            if (IS_FLOATING(value)) return !AS_FLOATING(value);
#endif
            break;
    }
    KrkClass * type = krk_getType(value);
 
    if (type->_bool) {
        krk_push(value);
        KrkValue result = krk_callDirect(type->_bool,1);
        if (krk_currentThread.flags & KRK_THREAD_HAS_EXCEPTION) return 1;
        if (!IS_BOOLEAN(result)) {
            krk_runtimeError(vm.exceptions->typeError, "__bool__ should return bool, not %T", result);
            return 1;
        }
        return !AS_INTEGER(result);
    }
 
    /* If it has a length, and that length is 0, it's Falsey */
    if (type->_len) {
        krk_push(value);
        KrkValue result = krk_callDirect(type->_len,1);
        return !AS_INTEGER(result);
    }
    return 0; /* Assume anything else is truthy */
}
 
void krk_setMaximumRecursionDepth(size_t maxDepth) {
    krk_currentThread.maximumCallDepth = maxDepth;
    krk_currentThread.frames = realloc(krk_currentThread.frames, maxDepth * sizeof(KrkCallFrame));
}
 
void krk_initVM(int flags) {
#if !defined(KRK_DISABLE_THREADS) && defined(__APPLE__) && defined(__aarch64__)
    krk_forceThreadData();
#endif
 
    vm.globalFlags = flags & 0xFF00;
 
    /* Reset current thread */
    krk_resetStack();
    krk_currentThread.maximumCallDepth = KRK_CALL_FRAMES_MAX;
    krk_currentThread.frames   = calloc(krk_currentThread.maximumCallDepth,sizeof(KrkCallFrame));
    krk_currentThread.flags    = flags & 0x00FF;
    krk_currentThread.module   = NULL;
    vm.threads = &krk_currentThread;
    vm.threads->next = NULL;
 
    /* GC state */
    vm.objects = NULL;
    vm.bytesAllocated = 0;
    vm.nextGC = 1024 * 1024;
    vm.grayCount = 0;
    vm.grayCapacity = 0;
    vm.grayStack = NULL;
 
    /* Global objects */
    vm.exceptions = calloc(1,sizeof(struct Exceptions));
    vm.baseClasses = calloc(1,sizeof(struct BaseClasses));
    vm.specialMethodNames = calloc(METHOD__MAX,sizeof(KrkValue));
    krk_initTable(&vm.strings);
    krk_initTable(&vm.modules);
 
    /*
     * To make lookup faster, store these so we can don't have to keep boxing
     * and unboxing, copying/hashing etc.
     */
    struct { const char * s; size_t len; } _methods[] = {
    #define CACHED_METHOD(a,b,c) [METHOD_ ## a] = {b,sizeof(b)-1},
    #define SPECIAL_ATTRS(a,b)   [METHOD_ ## a] = {b,sizeof(b)-1},
    #include "methods.h"
    #undef CACHED_METHOD
    #undef SPECIAL_ATTRS
    };
    for (size_t i = 0; i < METHOD__MAX; ++i) {
        vm.specialMethodNames[i] = OBJECT_VAL(krk_copyString(_methods[i].s, _methods[i].len));
    }
 
    /* Build classes for basic types */
    _createAndBind_builtins();
    _createAndBind_type();
    _createAndBind_numericClasses();
    _createAndBind_strClass();
    _createAndBind_listClass();
    _createAndBind_tupleClass();
    _createAndBind_bytesClass();
    _createAndBind_dictClass();
    _createAndBind_functionClass();
    _createAndBind_rangeClass();
    _createAndBind_setClass();
    _createAndBind_sliceClass();
    _createAndBind_exceptions();
    _createAndBind_generatorClass();
    _createAndBind_longClass();
    _createAndBind_compilerClass();
 
    if (!(vm.globalFlags & KRK_GLOBAL_NO_DEFAULT_MODULES)) {
#ifndef KRK_NO_SYSTEM_MODULES
        krk_module_init_kuroko();
#endif
#ifndef KRK_DISABLE_THREADS
        krk_module_init_threading();
#endif
    }
 
#ifndef KRK_DISABLE_DEBUG
    krk_debug_init();
#endif
 
 
    /* The VM is now ready to start executing code. */
    krk_resetStack();
}
 
void krk_freeVM(void) {
    krk_freeTable(&vm.strings);
    krk_freeTable(&vm.modules);
    if (vm.specialMethodNames) free(vm.specialMethodNames);
    if (vm.exceptions) free(vm.exceptions);
    if (vm.baseClasses) free(vm.baseClasses);
    krk_freeObjects();
 
    if (vm.binpath) free(vm.binpath);
    if (vm.dbgState) free(vm.dbgState);
 
    while (krk_currentThread.next) {
        KrkThreadState * thread = krk_currentThread.next;
        krk_currentThread.next = thread->next;
        KRK_FREE_ARRAY(size_t, thread->stack, thread->stackSize);
        free(thread->frames);
    }
 
    KRK_FREE_ARRAY(size_t, krk_currentThread.stack, krk_currentThread.stackSize);
    memset(&krk_vm,0,sizeof(krk_vm));
    free(krk_currentThread.frames);
    memset(&krk_currentThread,0,sizeof(KrkThreadState));
 
    extern void krk_freeMemoryDebugger(void);
    krk_freeMemoryDebugger();
}
 
const char * krk_typeName(KrkValue value) {
    return krk_getType(value)->name->chars;
}
 
static int _try_op(size_t methodOffset, KrkValue a, KrkValue b, KrkValue *out) {
    KrkClass * type = krk_getType(a);
    KrkObj * method = *(KrkObj**)((char*)type + methodOffset);
    if (likely(method != NULL)) {
        krk_push(a);
        krk_push(b);
        KrkValue result = krk_callDirect(method, 2);
        if (likely(!IS_NOTIMPL(result))) {
            *out = result;
            return 1;
        }
        if (krk_currentThread.flags & KRK_THREAD_HAS_EXCEPTION) {
            *out = NONE_VAL();
            return 1;
        }
    }
    return 0;
}
 
static KrkValue _bin_op(size_t methodOffset, size_t invOffset, const char * operator, KrkValue a, KrkValue b) {
    KrkValue result;
    if (_try_op(methodOffset, a, b, &result)) return result;
    if (_try_op(invOffset, b, a, &result)) return result;
    return krk_runtimeError(vm.exceptions->typeError,
        "unsupported operand types for %s: '%T' and '%T'",
        operator, a, b);
}
 
#define MAKE_COMPARE_OP(name,operator,inv) \
    _protected KrkValue krk_operator_ ## name (KrkValue a, KrkValue b) { \
        return _bin_op(offsetof(KrkClass,_ ## name),offsetof(KrkClass,_ ## inv), operator, a, b); \
    }
#define MAKE_BIN_OP(name,operator,inv) \
    MAKE_COMPARE_OP(name,operator,inv) \
    _protected KrkValue krk_operator_i ## name (KrkValue a, KrkValue b) { \
        KrkValue result; \
        if (_try_op(offsetof(KrkClass,_i ## name), a, b, &result)) return result; \
        return krk_operator_ ## name(a,b); \
    }
 
MAKE_BIN_OP(add,"+",radd)
MAKE_BIN_OP(sub,"-",rsub)
MAKE_BIN_OP(mul,"*",rmul)
MAKE_BIN_OP(pow,"**",rpow)
MAKE_BIN_OP(or,"|",ror)
MAKE_BIN_OP(xor,"^",rxor)
MAKE_BIN_OP(and,"&",rand)
MAKE_BIN_OP(lshift,"<<",rlshift)
MAKE_BIN_OP(rshift,">>",rrshift)
MAKE_BIN_OP(mod,"%",rmod)
MAKE_BIN_OP(truediv,"/",rtruediv)
MAKE_BIN_OP(floordiv,"//",rfloordiv)
MAKE_BIN_OP(matmul,"@",rmatmul)
 
MAKE_COMPARE_OP(lt, "<", gt)
MAKE_COMPARE_OP(gt, ">", lt)
MAKE_COMPARE_OP(le, "<=", ge)
MAKE_COMPARE_OP(ge, ">=", le)
 
_protected
KrkValue krk_operator_eq(KrkValue a, KrkValue b) {
    return BOOLEAN_VAL(krk_valuesEqual(a,b));
}
 
_protected
KrkValue krk_operator_is(KrkValue a, KrkValue b) {
    return BOOLEAN_VAL(krk_valuesSame(a,b));
}
 
static KrkValue _unary_op(size_t methodOffset, const char * operator, KrkValue value) {
    KrkClass * type = krk_getType(value);
    KrkObj * method = *(KrkObj**)((char*)type + methodOffset);
    if (likely(method != NULL)) {
        krk_push(value);
        return krk_callDirect(method, 1);
    }
    if (krk_currentThread.flags & KRK_THREAD_HAS_EXCEPTION) return NONE_VAL();
    return krk_runtimeError(vm.exceptions->typeError, "bad operand type for unary %s: '%T'", operator, value);
}
 
#define MAKE_UNARY_OP(sname,operator,op) \
    _protected KrkValue krk_operator_ ## operator (KrkValue value) { \
        return _unary_op(offsetof(KrkClass,sname),#op,value); \
    }
 
MAKE_UNARY_OP(_invert,invert,~)
MAKE_UNARY_OP(_negate,neg,-)
MAKE_UNARY_OP(_pos,pos,+)
 
static int handleException(void) {
    int stackOffset, frameOffset;
    int exitSlot = (krk_currentThread.exitOnFrame >= 0) ? krk_currentThread.frames[krk_currentThread.exitOnFrame].outSlots : 0;
    for (stackOffset = (int)(krk_currentThread.stackTop - krk_currentThread.stack - 1);
        stackOffset >= exitSlot &&
        !IS_HANDLER_TYPE(krk_currentThread.stack[stackOffset], OP_PUSH_TRY) &&
        !IS_HANDLER_TYPE(krk_currentThread.stack[stackOffset], OP_PUSH_WITH) &&
        !IS_HANDLER_TYPE(krk_currentThread.stack[stackOffset], OP_FILTER_EXCEPT) &&
        !IS_HANDLER_TYPE(krk_currentThread.stack[stackOffset], OP_RAISE) &&
        !IS_HANDLER_TYPE(krk_currentThread.stack[stackOffset], OP_END_FINALLY)
        ; stackOffset--);
    if (stackOffset < exitSlot) {
        if (exitSlot == 0) {
            /*
             * No exception was found and we have reached the top of the call stack.
             * Call dumpTraceback to present the exception to the user and reset the
             * VM stack state. It should still be safe to execute more code after
             * this reset, so the repl can throw errors and keep accepting new lines.
             */
            if (!(vm.globalFlags & KRK_GLOBAL_CLEAN_OUTPUT)) krk_dumpTraceback();
        }
        krk_currentThread.frameCount = krk_currentThread.exitOnFrame;
 
        /* Ensure stack is in the expected place, as if we returned None. */
        closeUpvalues(exitSlot);
        krk_currentThread.stackTop = &krk_currentThread.stack[exitSlot];
 
        /* If exitSlot was not 0, there was an exception during a call to runNext();
         * this is likely to be raised higher up the stack as an exception in the outer
         * call, but we don't want to print the traceback here. */
        return 1;
    }
 
    /* Find the call frame that owns this stack slot */
    for (frameOffset = krk_currentThread.frameCount - 1; frameOffset >= 0 && (int)krk_currentThread.frames[frameOffset].slots > stackOffset; frameOffset--);
    if (frameOffset == -1) {
        abort();
    }
 
    /* We found an exception handler and can reset the VM to its call frame. */
    closeUpvalues(stackOffset);
    krk_currentThread.stackTop = krk_currentThread.stack + stackOffset + 1;
    krk_currentThread.frameCount = frameOffset + 1;
 
    /* Clear the exception flag so we can continue executing from the handler. */
    krk_currentThread.flags &= ~KRK_THREAD_HAS_EXCEPTION;
    return 0;
}
 
int krk_loadModule(KrkString * path, KrkValue * moduleOut, KrkString * runAs, KrkValue parent) {
    /* See if the module is already loaded */
    if (krk_tableGet_fast(&vm.modules, runAs, moduleOut)) {
        krk_push(*moduleOut);
        return 1;
    }
 
#ifndef KRK_NO_FILESYSTEM
    KrkValue modulePaths;
 
    /* Obtain __builtins__.module_paths */
    if (!vm.system || !krk_tableGet_fast(&vm.system->fields, S("module_paths"), &modulePaths)) {
        *moduleOut = NONE_VAL();
        krk_runtimeError(vm.exceptions->importError, "kuroko.module_paths not defined.");
        return 0;
    }
 
    if (!IS_list(modulePaths)) {
        *moduleOut = NONE_VAL();
        krk_runtimeError(vm.exceptions->importError, "kuroko.module_paths must be a list, not '%T'", modulePaths);
        return 0;
    }
 
    /* Obtain __builtins__.module_paths.__list so we can do lookups directly */
    int moduleCount = AS_LIST(modulePaths)->count;
    if (!moduleCount) {
        *moduleOut = NONE_VAL();
        krk_runtimeError(vm.exceptions->importError,
            "No module search directories are specified, so no modules may be imported.");
        return 0;
    }
 
    struct stat statbuf;
 
    /* First search for {path}.krk in the module search paths */
    for (int i = 0; i < moduleCount; ++i, krk_pop()) {
        int isPackage = 0;
        char * fileName;
 
        krk_push(AS_LIST(modulePaths)->values[i]);
        if (!IS_STRING(krk_peek(0))) {
            *moduleOut = NONE_VAL();
            krk_runtimeError(vm.exceptions->typeError,
                "Module search path must be str, not '%T'", krk_peek(0));
            return 0;
        }
 
        /* Try .../path/__init__.krk */
        krk_push(OBJECT_VAL(path));
        krk_addObjects();
        krk_push(OBJECT_VAL(S(KRK_PATH_SEP "__init__.krk")));
        krk_addObjects();
        fileName = AS_CSTRING(krk_peek(0));
        if (stat(fileName,&statbuf) == 0) {
            isPackage = 1;
            if (runAs == S("__main__")) {
                krk_pop(); /* concatenated name */
 
                /* Convert back to .-formatted */
                krk_push(krk_valueGetAttribute(OBJECT_VAL(path), "replace"));
                krk_push(OBJECT_VAL(S(KRK_PATH_SEP)));
                krk_push(OBJECT_VAL(S(".")));
                krk_push(krk_callStack(2));
                KrkValue packageName = krk_peek(0);
                krk_push(packageName);
                krk_push(OBJECT_VAL(S(".")));
                krk_addObjects();
                krk_push(OBJECT_VAL(runAs));
                krk_addObjects();
 
                /* Try to import that. */
                KrkValue dotted_main = krk_peek(0);
                if (!krk_importModule(AS_STRING(dotted_main),runAs)) {
                    krk_runtimeError(vm.exceptions->importError, "No module named '%S'; '%S' is a package and cannot be executed directly",
                        AS_STRING(dotted_main), AS_STRING(packageName));
                    return 0;
                }
 
                krk_swap(2);
                krk_pop(); /* package name */
                krk_pop(); /* dotted_main */
                *moduleOut = krk_peek(0);
                return 1;
            }
            goto _normalFile;
        }
 
#ifndef KRK_STATIC_ONLY
        /* Try .../path.so */
        krk_pop();
        krk_push(AS_LIST(modulePaths)->values[i]);
        krk_push(OBJECT_VAL(path));
        krk_addObjects(); /* Concatenate path... */
        krk_push(OBJECT_VAL(S(".so")));
        krk_addObjects(); /* and file extension */
        fileName = AS_CSTRING(krk_peek(0));
        if (stat(fileName,&statbuf) == 0) {
            goto _sharedObject;
        }
#endif
 
        /* Try .../path.krk */
        krk_pop();
        krk_push(AS_LIST(modulePaths)->values[i]);
        krk_push(OBJECT_VAL(path));
        krk_addObjects(); /* Concatenate path... */
        krk_push(OBJECT_VAL(S(".krk")));
        krk_addObjects(); /* and file extension */
        fileName = AS_CSTRING(krk_peek(0));
        if (stat(fileName,&statbuf) == 0) {
            goto _normalFile;
        }
 
        /* Try next search path */
        continue;
 
    _normalFile: (void)0;
        /* Compile and run the module in a new context and exit the VM when it
         * returns to the current call frame; modules should return objects. */
        KrkInstance * enclosing = krk_currentThread.module;
        krk_startModule(runAs->chars);
        if (isPackage) {
            krk_attachNamedValue(&krk_currentThread.module->fields,"__ispackage__",BOOLEAN_VAL(1));
            /* For a module that is a package, __package__ is its own name */
            krk_attachNamedValue(&krk_currentThread.module->fields,"__package__",OBJECT_VAL(runAs));
        } else {
            KrkValue parentName;
            if (IS_INSTANCE(parent) && krk_tableGet_fast(&AS_INSTANCE(parent)->fields, S("__name__"), &parentName) && IS_STRING(parentName)) {
                krk_attachNamedValue(&krk_currentThread.module->fields, "__package__", parentName);
            } else {
                /* If there is no parent, or the parent doesn't have a string __name__ attribute,
                 * set the __package__ to None, so it at least exists. */
                krk_attachNamedValue(&krk_currentThread.module->fields, "__package__", NONE_VAL());
            }
        }
        krk_runfile(fileName,fileName);
        *moduleOut = OBJECT_VAL(krk_currentThread.module);
        krk_currentThread.module = enclosing;
        if (!IS_OBJECT(*moduleOut) || (krk_currentThread.flags & KRK_THREAD_HAS_EXCEPTION)) {
            if (!(krk_currentThread.flags & KRK_THREAD_HAS_EXCEPTION)) {
                krk_runtimeError(vm.exceptions->importError,
                    "Failed to load module '%S' from '%s'", runAs, fileName);
            }
            krk_tableDelete(&vm.modules, OBJECT_VAL(runAs));
            return 0;
        }
 
        krk_pop(); /* concatenated filename on stack */
        krk_push(*moduleOut);
        return 1;
 
#ifndef KRK_STATIC_ONLY
    _sharedObject: (void)0;
 
        krk_dlRefType dlRef = krk_dlOpen(fileName);
        if (!dlRef) {
            *moduleOut = NONE_VAL();
            krk_runtimeError(vm.exceptions->importError,
                "Failed to load native module '%S' from shared object '%s'", runAs, fileName);
            return 0;
        }
 
        const char * start = path->chars;
        for (const char * c = start; *c; c++) {
            if (*c == '/') start = c + 1;
        }
 
        krk_push(OBJECT_VAL(S("krk_module_onload_")));
        krk_push(OBJECT_VAL(krk_copyString(start,strlen(start))));
        krk_addObjects();
 
        char * handlerName = AS_CSTRING(krk_peek(0));
 
        KrkValue (*moduleOnLoad)(KrkString * name);
        krk_dlSymType out = krk_dlSym(dlRef, handlerName);
        memcpy(&moduleOnLoad,&out,sizeof(out));
 
        if (!moduleOnLoad) {
            krk_dlClose(dlRef);
            *moduleOut = NONE_VAL();
            krk_runtimeError(vm.exceptions->importError,
                "Failed to run module initialization method '%s' from shared object '%s'",
                handlerName, fileName);
            return 0;
        }
 
        krk_pop(); /* onload function */
 
        *moduleOut = moduleOnLoad(runAs);
        if (!krk_isInstanceOf(*moduleOut, vm.baseClasses->moduleClass)) {
            krk_dlClose(dlRef);
            krk_runtimeError(vm.exceptions->importError,
                "Failed to load module '%S' from '%s'", runAs, fileName);
            return 0;
        }
 
        krk_push(*moduleOut);
        krk_swap(1);
 
        struct KrkModule * moduleAsStruct = (struct KrkModule*)AS_INSTANCE(*moduleOut);
        moduleAsStruct->libHandle = dlRef;
 
        krk_attachNamedObject(&AS_INSTANCE(*moduleOut)->fields, "__name__", (KrkObj*)runAs);
        krk_attachNamedValue(&AS_INSTANCE(*moduleOut)->fields, "__file__", krk_peek(0));
 
        krk_pop(); /* filename */
        krk_tableSet(&vm.modules, OBJECT_VAL(runAs), *moduleOut);
        return 1;
#endif
    }
 
#endif
 
    /* If we still haven't found anything, fail. */
    *moduleOut = NONE_VAL();
 
    /* Was this a __main__? */
    if (runAs == S("__main__")) {
        /* Then let's use 'path' instead, and replace all the /'s with .'s... */
        krk_push(krk_valueGetAttribute(OBJECT_VAL(path), "replace"));
        krk_push(OBJECT_VAL(S(KRK_PATH_SEP)));
        krk_push(OBJECT_VAL(S(".")));
        krk_push(krk_callStack(2));
    } else {
        krk_push(OBJECT_VAL(runAs));
    }
 
    krk_runtimeError(vm.exceptions->importError, "No module named '%S'", AS_STRING(krk_peek(0)));
 
    return 0;
}
 
int krk_importModule(KrkString * name, KrkString * runAs) {
    /* See if 'name' is clear to directly import */
    int isClear = 1;
    for (size_t i = 0; i < name->length; ++i) {
        if (name->chars[i] == '.') {
            isClear = 0;
            break;
        }
    }
 
    if (isClear) {
        KrkValue base;
        return krk_loadModule(name,&base,runAs,NONE_VAL());
    }
 
    if (name->chars[0] == '.') {
        KrkValue packageName;
        if (!krk_tableGet_fast(&krk_currentThread.module->fields, S("__package__"), &packageName) || !IS_STRING(packageName)) {
            /* We must have __package__ set to a string for this to make any sense. */
            krk_runtimeError(vm.exceptions->importError, "attempted relative import without a package context");
            return 0;
        }
 
        if (name->length == 1) {
            /* from . import ... */
            return krk_importModule(AS_STRING(packageName), AS_STRING(packageName));
        }
 
        if (name->chars[1] != '.') {
            /* from .something import ... */
            krk_push(packageName);
            krk_push(OBJECT_VAL(name));
            krk_addObjects();
 
            if (krk_importModule(AS_STRING(krk_peek(0)), AS_STRING(krk_peek(0)))) {
                krk_swap(1); /* Imported module */
                krk_pop(); /* Name */
                return 1;
            }
 
            return 0;
        }
 
        size_t dots = 0;
        while (name->chars[dots+1] == '.') dots++;
 
        /* We'll split the package name is str.split(__package__,'.') */
        krk_push(packageName);
        krk_push(OBJECT_VAL(S(".")));
        KrkValue components = krk_string_split(2,(KrkValue[]){krk_peek(1),krk_peek(0)}, 0);
        if (!IS_list(components)) {
            krk_runtimeError(vm.exceptions->importError, "internal error while calculating package path");
            return 0;
        }
        krk_push(components);
        krk_swap(2);
        krk_pop();
        krk_pop();
 
        /* If there are not enough components to "go up" through, that's an error. */
        if (AS_LIST(components)->count <= dots) {
            krk_runtimeError(vm.exceptions->importError, "attempted relative import beyond top-level package");
            return 0;
        }
 
        size_t count = AS_LIST(components)->count - dots;
        struct StringBuilder sb = {0};
 
        /* Now rebuild the dotted form from the remaining components... */
        for (size_t i = 0; i < count; i++) {
            KrkValue node = AS_LIST(components)->values[i];
            if (!IS_STRING(node)) {
                discardStringBuilder(&sb);
                krk_runtimeError(vm.exceptions->importError, "internal error while calculating package path");
                return 0;
            }
            pushStringBuilderStr(&sb, AS_CSTRING(node), AS_STRING(node)->length);
            if (i + 1 != count) {
                pushStringBuilder(&sb, '.');
            }
        }
 
        krk_pop(); /* components */
 
        if (name->chars[dots+1]) {
            /* from ..something import ... - append '.something' */
            pushStringBuilderStr(&sb, &name->chars[dots], name->length - dots);
        }
 
        krk_push(finishStringBuilder(&sb));
 
        /* Now to try to import the fully qualified module path */
        if (krk_importModule(AS_STRING(krk_peek(0)), AS_STRING(krk_peek(0)))) {
            krk_swap(1); /* Imported module */
            krk_pop(); /* Name */
            return 1;
        }
        return 0;
    }
 
    /* Let's split up name */
    krk_push(NONE_VAL());         // -1: last
    int argBase = krk_currentThread.stackTop - krk_currentThread.stack;
    krk_push(NONE_VAL());         // 0: Name of current node being processed.
    krk_push(OBJECT_VAL(S("")));  // 1: slash/separated/path
    krk_push(OBJECT_VAL(S("")));  // 2: dot.separated.path
    krk_push(OBJECT_VAL(name));   // 3: remaining path to process
    krk_push(OBJECT_VAL(S("."))); // 4: string "." to search for
    do {
        KrkValue listOut = krk_string_split(3,(KrkValue[]){krk_currentThread.stack[argBase+3], krk_currentThread.stack[argBase+4], INTEGER_VAL(1)}, 0);
        if (!IS_INSTANCE(listOut)) return 0;
 
        /* Set node */
        krk_currentThread.stack[argBase+0] = AS_LIST(listOut)->values[0];
 
        /* Set remainder */
        if (AS_LIST(listOut)->count > 1) {
            krk_currentThread.stack[argBase+3] = AS_LIST(listOut)->values[1];
        } else {
            krk_currentThread.stack[argBase+3] = NONE_VAL();
        }
 
        /* First is /-path */
        krk_push(krk_currentThread.stack[argBase+1]);
        krk_push(krk_currentThread.stack[argBase+0]);
        krk_addObjects();
        krk_currentThread.stack[argBase+1] = krk_pop();
        /* Second is .-path */
        krk_push(krk_currentThread.stack[argBase+2]);
        krk_push(krk_currentThread.stack[argBase+0]);
        krk_addObjects();
        krk_currentThread.stack[argBase+2] = krk_pop();
 
        if (IS_NONE(krk_currentThread.stack[argBase+3])) {
            krk_pop(); /* dot */
            krk_pop(); /* remainder */
            KrkValue current;
            if (!krk_loadModule(AS_STRING(krk_currentThread.stack[argBase+1]), &current, runAs, krk_currentThread.stack[argBase-1])) return 0;
            krk_pop(); /* dot-sepaerated */
            krk_pop(); /* slash-separated */
            krk_push(current);
            /* last must be something if we got here, because single-level import happens elsewhere */
            krk_tableSet(&AS_INSTANCE(krk_currentThread.stack[argBase-1])->fields, krk_currentThread.stack[argBase+0], krk_peek(0));
            krk_currentThread.stackTop = krk_currentThread.stack + argBase;
            krk_currentThread.stackTop[-1] = current;
            return 1;
        } else {
            KrkValue current;
            if (!krk_loadModule(AS_STRING(krk_currentThread.stack[argBase+1]), &current, AS_STRING(krk_currentThread.stack[argBase+2]),NONE_VAL())) return 0;
            krk_push(current);
            if (!IS_NONE(krk_currentThread.stack[argBase-1])) {
                krk_tableSet(&AS_INSTANCE(krk_currentThread.stack[argBase-1])->fields, krk_currentThread.stack[argBase+0], krk_peek(0));
            }
            /* Is this a package? */
            KrkValue tmp;
            if (!krk_tableGet_fast(&AS_INSTANCE(current)->fields, S("__ispackage__"), &tmp) || !IS_BOOLEAN(tmp) || AS_BOOLEAN(tmp) != 1) {
                krk_runtimeError(vm.exceptions->importError, "'%S' is not a package", AS_STRING(krk_currentThread.stack[argBase+2]));
                return 0;
            }
            krk_currentThread.stack[argBase-1] = krk_pop();
            /* Now concatenate forward slash... */
            krk_push(krk_currentThread.stack[argBase+1]); /* Slash path */
            krk_push(OBJECT_VAL(S(KRK_PATH_SEP)));
            krk_addObjects();
            krk_currentThread.stack[argBase+1] = krk_pop();
            /* And now for the dot... */
            krk_push(krk_currentThread.stack[argBase+2]);
            krk_push(krk_currentThread.stack[argBase+4]);
            krk_addObjects();
            krk_currentThread.stack[argBase+2] = krk_pop();
        }
    } while (1);
}
 
int krk_doRecursiveModuleLoad(KrkString * name) {
    return krk_importModule(name,name);
}
 
#define CACHE_SIZE 4096
typedef struct {
    KrkString * name;
    struct KrkClass  * owner;
    KrkValue    value;
    size_t index;
} KrkClassCacheEntry;
static KrkClassCacheEntry cache[CACHE_SIZE] = {0};
static size_t nextCount = 1;
 
static KrkClass * checkCache(KrkClass * type, KrkString * name, KrkValue * method) {
    size_t index = (name->obj.hash ^ (type->obj.hash << 4)) & (CACHE_SIZE-1);
    KrkClassCacheEntry * entry = &cache[index];
    if (entry->name == name && entry->index == type->cacheIndex) {
        *method = entry->value;
        return entry->owner;
    }
 
    KrkClass * _class = NULL;
    if (krk_tableGet_fast(&type->methods, name, method)) {
        _class = type;
    } else if (type->base) {
        _class = checkCache(type->base, name, method);
    }
 
    if (!type->cacheIndex) {
        type->cacheIndex = nextCount++;
    }
    entry->name = name;
    entry->owner = _class;
    entry->value = *method;
    entry->index = type->cacheIndex;
    return _class;
}
 
static void clearCache(KrkClass * type) {
    if (type->cacheIndex) {
        type->cacheIndex = 0;
        for (size_t i = 0; i < type->subclasses.capacity; ++i) {
            KrkTableEntry * entry = &type->subclasses.entries[i];
            if (krk_valuesSame(entry->key, KWARGS_VAL(0))) continue;
            clearCache(AS_CLASS(entry->key));
        }
    }
}
 
int krk_bindMethodSuper(KrkClass * originalClass, KrkString * name, KrkClass * realClass) {
    KrkValue method, out;
    KrkClass * _class = checkCache(originalClass, name, &method);
    if (!_class) return 0;
    if (IS_NATIVE(method)||IS_CLOSURE(method)) {
        if (AS_OBJECT(method)->flags & KRK_OBJ_FLAGS_FUNCTION_IS_CLASS_METHOD) {
            out = OBJECT_VAL(krk_newBoundMethod(OBJECT_VAL(realClass), AS_OBJECT(method)));
        } else if (IS_NONE(krk_peek(0)) || (AS_OBJECT(method)->flags & KRK_OBJ_FLAGS_FUNCTION_IS_STATIC_METHOD)) {
            out = method;
        } else {
            out = OBJECT_VAL(krk_newBoundMethod(krk_peek(0), AS_OBJECT(method)));
        }
    } else {
        /* Does it have a descriptor __get__? */
        KrkClass * type = krk_getType(method);
        if (type->_descget) {
            krk_push(method);
            krk_swap(1);
            krk_push(OBJECT_VAL(realClass));
            krk_push(krk_callDirect(type->_descget, 3));
            return 1;
        }
        out = method;
    }
    krk_pop();
    krk_push(out);
    return 1;
}
 
int krk_bindMethod(KrkClass * originalClass, KrkString * name) {
    return krk_bindMethodSuper(originalClass,name,originalClass);
}
 
static int valueGetMethod(KrkString * name) {
    KrkValue this = krk_peek(0);
    KrkClass * myClass = krk_getType(this);
    KrkValue value, method;
    KrkClass * _class = checkCache(myClass, name, &method);
 
    /* Class descriptors */
    if (_class) {
        KrkClass * valtype = krk_getType(method);
        if (valtype->_descget && valtype->_descset) {
            krk_push(method);
            krk_push(this);
            krk_push(OBJECT_VAL(myClass));
            value = krk_callDirect(valtype->_descget, 3);
            goto found;
        }
    }
 
    /* Fields */
    if (IS_INSTANCE(this)) {
        if (krk_tableGet_fast(&AS_INSTANCE(this)->fields, name, &value)) goto found;
    } else if (IS_CLASS(this)) {
        KrkClass * type = AS_CLASS(this);
        do {
            if (krk_tableGet_fast(&type->methods, name, &value)) {
                if ((IS_NATIVE(value) || IS_CLOSURE(value)) && (AS_OBJECT(value)->flags & KRK_OBJ_FLAGS_FUNCTION_IS_CLASS_METHOD)) {
                    goto found_method;
                }
                KrkClass * valtype = krk_getType(value);
                if (valtype->_descget) {
                    krk_push(value);
                    krk_push(NONE_VAL());
                    krk_push(this);
                    value = krk_callDirect(valtype->_descget, 3);
                }
                goto found;
            }
            type = type->base;
        } while (type);
    } else if (IS_CLOSURE(this)) {
        if (krk_tableGet_fast(&AS_CLOSURE(this)->fields, name, &value)) goto found;
    }
 
    /* Method from type */
    if (_class) {
        if (IS_NATIVE(method)||IS_CLOSURE(method)) {
            if (AS_OBJECT(method)->flags & KRK_OBJ_FLAGS_FUNCTION_IS_CLASS_METHOD) {
                krk_currentThread.stackTop[-1] = OBJECT_VAL(myClass);
                value = method;
                goto found_method;
            } else if (AS_OBJECT(method)->flags & KRK_OBJ_FLAGS_FUNCTION_IS_STATIC_METHOD) {
                value = method;
            } else {
                value = method;
                goto found_method;
            }
        } else {
            KrkClass * valtype = krk_getType(method);
            if (valtype->_descget) {
                krk_push(method);
                krk_push(this);
                krk_push(OBJECT_VAL(myClass));
                value = krk_callDirect(valtype->_descget, 3);
                goto found;
            }
            value = method;
        }
        goto found;
    }
 
    /* __getattr__ */
    if (myClass->_getattr) {
        krk_push(this);
        krk_push(OBJECT_VAL(name));
        value = krk_callDirect(myClass->_getattr, 2);
        goto found;
    }
 
    return 0;
 
found:
    krk_push(value);
    return 2;
 
found_method:
    krk_push(value);
    return 1;
}
 
static int valueGetProperty(KrkString * name) {
    switch (valueGetMethod(name)) {
        case 2:
            krk_currentThread.stackTop[-2] = krk_currentThread.stackTop[-1];
            krk_currentThread.stackTop--;
            return 1;
        case 1: {
            KrkValue o = OBJECT_VAL(krk_newBoundMethod(krk_currentThread.stackTop[-2], AS_OBJECT(krk_currentThread.stackTop[-1])));
            krk_currentThread.stackTop[-2] = o;
            krk_currentThread.stackTop--;
            return 1;
        }
        default:
            return 0;
    }
}
 
int krk_getAttribute(KrkString * name) {
    return valueGetProperty(name);
}
 
KrkValue krk_valueGetAttribute(KrkValue value, char * name) {
    krk_push(OBJECT_VAL(krk_copyString(name,strlen(name))));
    krk_push(value);
    if (!valueGetProperty(AS_STRING(krk_peek(1)))) {
        return krk_runtimeError(vm.exceptions->attributeError, "'%T' object has no attribute '%s'", krk_peek(0), name);
    }
    krk_swap(1);
    krk_pop(); /* String */
    return krk_pop();
}
 
KrkValue krk_valueGetAttribute_default(KrkValue value, char * name, KrkValue defaultVal) {
    krk_push(OBJECT_VAL(krk_copyString(name,strlen(name))));
    krk_push(value);
    if (!valueGetProperty(AS_STRING(krk_peek(1)))) {
        krk_pop();
        krk_pop();
        return defaultVal;
    }
    krk_swap(1);
    krk_pop(); /* String */
    return krk_pop();
}
 
static int valueDelProperty(KrkString * name) {
    if (IS_INSTANCE(krk_peek(0))) {
        KrkInstance* instance = AS_INSTANCE(krk_peek(0));
        if (!krk_tableDelete(&instance->fields, OBJECT_VAL(name))) {
            return 0;
        }
        krk_pop(); /* the original value */
        return 1;
    } else if (IS_CLASS(krk_peek(0))) {
        KrkClass * _class = AS_CLASS(krk_peek(0));
        if (!krk_tableDelete(&_class->methods, OBJECT_VAL(name))) {
            return 0;
        }
        if (name->length > 1 && name->chars[0] == '_' && name->chars[1] == '_') {
            krk_finalizeClass(_class);
        } else {
            clearCache(_class);
        }
        krk_pop(); /* the original value */
        return 1;
    } else if (IS_CLOSURE(krk_peek(0))) {
        KrkClosure * closure = AS_CLOSURE(krk_peek(0));
        if (!krk_tableDelete(&closure->fields, OBJECT_VAL(name))) {
            return 0;
        }
        krk_pop();
        return 1;
    }
    /* TODO __delattr__? Descriptor __delete__ methods? */
    return 0;
}
 
int krk_delAttribute(KrkString * name) {
    return valueDelProperty(name);
}
 
KrkValue krk_valueDelAttribute(KrkValue owner, char * name) {
    krk_push(OBJECT_VAL(krk_copyString(name,strlen(name))));
    krk_push(owner);
    if (!valueDelProperty(AS_STRING(krk_peek(1)))) {
        return krk_runtimeError(vm.exceptions->attributeError, "'%T' object has no attribute '%s'", krk_peek(0), name);
    }
    krk_pop(); /* String */
    return NONE_VAL();
}
 
static int _setDescriptor(KrkValue owner, KrkClass * _class, KrkString * name, KrkValue to) {
    KrkValue property;
    _class = checkCache(_class, name, &property);
    if (_class) {
        KrkClass * type = krk_getType(property);
        if (type->_descset) {
            krk_push(property);
            krk_push(owner);
            krk_push(to);
            krk_push(krk_callDirect(type->_descset, 3));
            return 1;
        }
    }
    return 0;
}
 
static KrkValue setAttr_wrapper(KrkValue owner, KrkClass * _class, KrkTable * fields, KrkString * name, KrkValue to) {
    if (_setDescriptor(owner,_class,name,to)) return krk_pop();
    krk_tableSet(fields, OBJECT_VAL(name), to);
    return to;
}
 
_noexport
KrkValue krk_instanceSetAttribute_wrapper(KrkValue owner, KrkString * name, KrkValue to) {
    return setAttr_wrapper(owner, AS_INSTANCE(owner)->_class, &AS_INSTANCE(owner)->fields, name, to);
}
 
static int valueSetProperty(KrkString * name) {
    KrkValue owner = krk_peek(1);
    KrkValue value = krk_peek(0);
    KrkClass * type = krk_getType(owner);
    if (unlikely(type->_setattr != NULL)) {
        krk_push(OBJECT_VAL(name));
        krk_swap(1);
        krk_push(krk_callDirect(type->_setattr, 3));
        return 1;
    }
    if (IS_INSTANCE(owner)) {
        KrkValue o = setAttr_wrapper(owner,type,&AS_INSTANCE(owner)->fields, name, value);
        krk_currentThread.stackTop[-1] = o;
    } else if (IS_CLASS(owner)) {
        KrkValue o = setAttr_wrapper(owner,type,&AS_CLASS(owner)->methods, name, value);
        krk_currentThread.stackTop[-1] = o;
        if (name->length > 1 && name->chars[0] == '_' && name->chars[1] == '_') {
            krk_finalizeClass(AS_CLASS(owner));
        } else {
            clearCache(AS_CLASS(owner));
        }
    } else if (IS_CLOSURE(owner)) {
        KrkValue o = setAttr_wrapper(owner,type,&AS_CLOSURE(owner)->fields, name, value);
        krk_currentThread.stackTop[-1] = o;
    } else {
        if (_setDescriptor(owner,type,name,value)) {
            krk_swap(1);
            krk_pop();
        } else {
            return 0;
        }
    }
    krk_swap(1);
    krk_pop();
    return 1;
}
 
int krk_setAttribute(KrkString * name) {
    return valueSetProperty(name);
}
 
KrkValue krk_valueSetAttribute(KrkValue owner, char * name, KrkValue to) {
    krk_push(OBJECT_VAL(krk_copyString(name,strlen(name))));
    krk_push(owner);
    krk_push(to);
    if (!valueSetProperty(AS_STRING(krk_peek(2)))) {
        return krk_runtimeError(vm.exceptions->attributeError, "'%T' object has no attribute '%s'", krk_peek(1), name);
    }
    krk_swap(1);
    krk_pop(); /* String */
    return krk_pop();
}
 
#define BINARY_OP(op) { KrkValue b = krk_peek(0); KrkValue a = krk_peek(1); \
    a = krk_operator_ ## op (a,b); \
    krk_currentThread.stackTop[-2] = a; krk_pop(); break; }
#define INPLACE_BINARY_OP(op) { KrkValue b = krk_peek(0); KrkValue a = krk_peek(1); \
    a = krk_operator_i ## op (a,b); \
    krk_currentThread.stackTop[-2] = a; krk_pop(); break; }
 
extern KrkValue krk_int_op_add(krk_integer_type a, krk_integer_type b);
extern KrkValue krk_int_op_sub(krk_integer_type a, krk_integer_type b);
 
/* These operations are most likely to occur on integers, so we special case them */
#define LIKELY_INT_BINARY_OP(op) { KrkValue b = krk_peek(0); KrkValue a = krk_peek(1); \
    if (likely(IS_INTEGER(a) && IS_INTEGER(b))) a = krk_int_op_ ## op (AS_INTEGER(a), AS_INTEGER(b)); \
    else a = krk_operator_ ## op (a,b); \
    krk_currentThread.stackTop[-2] = a; krk_pop(); break; }
 
/* Comparators like these are almost definitely going to happen on integers. */
#define LIKELY_INT_COMPARE_OP(op,operator) { KrkValue b = krk_peek(0); KrkValue a = krk_peek(1); \
    if (likely(IS_INTEGER(a) && IS_INTEGER(b))) a = BOOLEAN_VAL(AS_INTEGER(a) operator AS_INTEGER(b)); \
    else a = krk_operator_ ## op (a,b); \
    krk_currentThread.stackTop[-2] = a; krk_pop(); break; }
 
#define LIKELY_INT_UNARY_OP(op,operator) { KrkValue a = krk_peek(0); \
    if (likely(IS_INTEGER(a))) a = INTEGER_VAL(operator AS_INTEGER(a)); \
    else a = krk_operator_ ## op (a); \
    krk_currentThread.stackTop[-1] = a; break; }
 
#define READ_BYTE() (*frame->ip++)
#define READ_CONSTANT(s) (frame->closure->function->chunk.constants.values[OPERAND])
#define READ_STRING(s) AS_STRING(READ_CONSTANT(s))
 
extern FUNC_SIG(list,append);
extern FUNC_SIG(dict,__setitem__);
extern FUNC_SIG(set,add);
extern FUNC_SIG(list,extend);
extern FUNC_SIG(dict,update);
extern FUNC_SIG(set,update);
 
struct ex_unpack {
    KrkTuple * output;
    unsigned char before;
    unsigned char after;
    KrkValue list;
    size_t total;
};
 
static int _unpack_ex(void * context, const KrkValue * values, size_t count) {
    struct ex_unpack * ctx = context;
 
    KrkTuple * output = ctx->output;
 
    for (size_t i = 0; i < count; ++i) {
        if (ctx->total < ctx->before) {
            output->values.values[output->values.count++] = values[i];
        } else if (ctx->total >= ctx->before) {
            if (ctx->total == ctx->before) {
                output->values.values[output->values.count++] = ctx->list;
            }
            FUNC_NAME(list,append)(2,(KrkValue[]){ctx->list,values[i]},0);
        }
        ctx->total++;
    }
 
    return 0;
}
 
 
static inline void makeCollection(NativeFn func, size_t count) {
    KrkValue collection = krk_callNativeOnStack(count, &krk_currentThread.stackTop[-count], 0, func);
    if (count) {
        krk_currentThread.stackTop[-count] = collection;
        while (count > 1) {
            krk_pop();
            count--;
        }
    } else {
        krk_push(collection);
    }
}
 
static inline int doFormatString(int options) {
    if (options & FORMAT_OP_FORMAT) {
        krk_swap(1);
        if (options & FORMAT_OP_EQ) {
            krk_swap(2);
        }
    } else if (options & FORMAT_OP_EQ) {
        krk_swap(1);
    }
 
    /* Was this a repr or str call? (it can't be both) */
    if (options & FORMAT_OP_STR) {
        KrkClass * type = krk_getType(krk_peek(0));
        if (likely(type->_tostr != NULL)) {
            krk_push(krk_callDirect(type->_tostr, 1));
            if (unlikely(krk_currentThread.flags & KRK_THREAD_HAS_EXCEPTION)) return 1;
        } else {
            krk_runtimeError(vm.exceptions->typeError,
                "Can not convert '%T' to str", krk_peek(0));
            return 1;
        }
    } else if (options & FORMAT_OP_REPR) {
        KrkClass * type = krk_getType(krk_peek(0));
        if (likely(type->_reprer != NULL)) {
            krk_push(krk_callDirect(type->_reprer, 1));
            if (unlikely(krk_currentThread.flags & KRK_THREAD_HAS_EXCEPTION)) return 1;
        } else {
            krk_runtimeError(vm.exceptions->typeError,
                "Can not repr '%T'", krk_peek(0));
            return 1;
        }
    }
 
    if (!(options & FORMAT_OP_FORMAT)) {
        /* Push empty string */
        krk_push(OBJECT_VAL(S("")));
    } else {
        /* Swap args so value is first */
        krk_swap(1);
    }
 
    /* Get the type of the value */
    KrkClass * type = krk_getType(krk_peek(1));
 
    if (likely(type->_format != NULL)) {
        krk_push(krk_callDirect(type->_format, 2));
        if (unlikely(krk_currentThread.flags & KRK_THREAD_HAS_EXCEPTION)) return 1;
    } else {
        krk_runtimeError(vm.exceptions->attributeError, "'%T' object has no attribute '%s'", krk_peek(1), "__format__");
        return 1;
    }
 
    if (!IS_STRING(krk_peek(0))) {
        krk_runtimeError(vm.exceptions->typeError, "format result is not str");
        return 1;
    }
 
    return 0;
}
 
static inline void commonMethodInvoke(size_t methodOffset, int args, const char * msgFormat) {
    KrkClass * type = krk_getType(krk_peek(args-1));
    KrkObj * method = *(KrkObj**)((char*)type + methodOffset);
    if (likely(method != NULL)) {
        krk_push(krk_callDirect(method, args));
    } else {
        krk_runtimeError(vm.exceptions->attributeError, msgFormat, krk_peek(args-1));
    }
}
 
int krk_isSubClass(const KrkClass * cls, const KrkClass * base) {
    while (cls) {
        if (cls == base) return 1;
        cls = cls->base;
    }
    return 0;
}
 
static KrkValue run(void) {
    KrkCallFrame* frame = &krk_currentThread.frames[krk_currentThread.frameCount - 1];
 
    while (1) {
        if (unlikely(krk_currentThread.flags & (KRK_THREAD_ENABLE_TRACING | KRK_THREAD_SINGLE_STEP | KRK_THREAD_SIGNALLED))) {
#if !defined(KRK_NO_TRACING) && !defined(KRK_DISABLE_DEBUG)
            if (krk_currentThread.flags & KRK_THREAD_ENABLE_TRACING) {
                krk_debug_dumpStack(stderr, frame);
                krk_disassembleInstruction(stderr, frame->closure->function,
                    (size_t)(frame->ip - frame->closure->function->chunk.code));
            }
#endif
 
#ifndef KRK_DISABLE_DEBUG
            if (krk_currentThread.flags & KRK_THREAD_SINGLE_STEP) {
                krk_debuggerHook(frame);
            }
#endif
 
            if (krk_currentThread.flags & KRK_THREAD_SIGNALLED) {
                krk_currentThread.flags &= ~(KRK_THREAD_SIGNALLED); /* Clear signal flag */
                krk_runtimeError(vm.exceptions->keyboardInterrupt, "Keyboard interrupt.");
                goto _finishException;
            }
        }
#ifndef KRK_DISABLE_DEBUG
_resumeHook: (void)0;
#endif
 
        /* Each instruction begins with one opcode byte */
        KrkOpCode opcode = READ_BYTE();
        unsigned int OPERAND = 0;
 
/* Only GCC lets us put these on empty statements; just hope clang doesn't start complaining */
#if defined(__GNUC__) && !defined(__clang__)
# define FALLTHROUGH __attribute__((fallthrough));
#else
# define FALLTHROUGH
#endif
 
#define TWO_BYTE_OPERAND { OPERAND = OPERAND | (frame->ip[0] << 8) | frame->ip[1]; frame->ip += 2; }
#define THREE_BYTE_OPERAND { OPERAND = (frame->ip[0] << 16) | (frame->ip[1] << 8); frame->ip += 2; } FALLTHROUGH
#define ONE_BYTE_OPERAND { OPERAND = (OPERAND & ~0xFF) | READ_BYTE(); }
 
_switchEntry: (void)0;
        switch (opcode) {
            case OP_CLEANUP_WITH: {
                /* Top of stack is a HANDLER that should have had something loaded into it if it was still valid */
                KrkValue handler = krk_peek(0);
                KrkValue exceptionObject = krk_peek(1);
                KrkValue contextManager = krk_peek(2);
                KrkClass * type = krk_getType(contextManager);
                krk_push(contextManager);
                if (AS_HANDLER_TYPE(handler) == OP_RAISE) {
                    krk_currentThread.stackTop[-2] = HANDLER_VAL(OP_CLEANUP_WITH,AS_HANDLER_TARGET(krk_peek(1)));
                    krk_push(OBJECT_VAL(krk_getType(exceptionObject)));
                    krk_push(exceptionObject);
                    KrkValue tracebackEntries = NONE_VAL();
                    if (IS_INSTANCE(exceptionObject))
                        krk_tableGet_fast(&AS_INSTANCE(exceptionObject)->fields, S("traceback"), &tracebackEntries);
                    krk_push(tracebackEntries);
                    krk_callDirect(type->_exit, 4);
                    /* Top of stack is now either someone else's problem or a return value */
                    if (!(krk_currentThread.flags & KRK_THREAD_HAS_EXCEPTION)) {
                        krk_pop(); /* Handler object */
                        krk_currentThread.currentException = krk_pop(); /* Original exception */
                        krk_currentThread.flags |= KRK_THREAD_HAS_EXCEPTION;
                    }
                    goto _finishException;
                } else {
                    krk_push(NONE_VAL());
                    krk_push(NONE_VAL());
                    krk_push(NONE_VAL());
                    krk_callDirect(type->_exit, 4);
                    if (krk_currentThread.flags & KRK_THREAD_HAS_EXCEPTION) goto _finishException;
                }
                if (AS_HANDLER_TYPE(handler) == OP_EXIT_LOOP) {
                    frame->ip = frame->closure->function->chunk.code + AS_HANDLER_TARGET(handler);
                    OPERAND = AS_INTEGER(krk_peek(1));
                    goto _finishPopBlock;
                }
                if (AS_HANDLER_TYPE(handler) != OP_RETURN) break;
                krk_pop(); /* handler */
            } /* fallthrough */
            case OP_RETURN: {
_finishReturn: (void)0;
                KrkValue result = krk_pop();
                /* See if this frame had a thing */
                int stackOffset;
                for (stackOffset = (int)(krk_currentThread.stackTop - krk_currentThread.stack - 1);
                    stackOffset >= (int)frame->slots && 
                    !IS_HANDLER_TYPE(krk_currentThread.stack[stackOffset],OP_PUSH_TRY) &&
                    !IS_HANDLER_TYPE(krk_currentThread.stack[stackOffset],OP_PUSH_WITH) &&
                    !IS_HANDLER_TYPE(krk_currentThread.stack[stackOffset],OP_FILTER_EXCEPT)
                    ; stackOffset--);
                if (stackOffset >= (int)frame->slots) {
                    closeUpvalues(stackOffset);
                    krk_currentThread.stackTop = &krk_currentThread.stack[stackOffset + 1];
                    frame->ip = frame->closure->function->chunk.code + AS_HANDLER_TARGET(krk_peek(0));
                    krk_currentThread.stackTop[-1] = HANDLER_VAL(OP_RETURN,AS_HANDLER_TARGET(krk_peek(0)));
                    krk_currentThread.stackTop[-2] = result;
                    break;
                }
                closeUpvalues(frame->slots);
                krk_currentThread.frameCount--;
                if (krk_currentThread.frameCount == 0) {
                    krk_pop();
                    return result;
                }
                krk_currentThread.stackTop = &krk_currentThread.stack[frame->outSlots];
                if (krk_currentThread.frameCount == (size_t)krk_currentThread.exitOnFrame) {
                    if (frame->closure->function->obj.flags & (KRK_OBJ_FLAGS_CODEOBJECT_IS_GENERATOR | KRK_OBJ_FLAGS_CODEOBJECT_IS_COROUTINE)) {
                        krk_push(result);
                        return KWARGS_VAL(0);
                    }
                    return result;
                }
                krk_push(result);
                frame = &krk_currentThread.frames[krk_currentThread.frameCount - 1];
                break;
            }
            case OP_LESS:          LIKELY_INT_COMPARE_OP(lt,<)
            case OP_GREATER:       LIKELY_INT_COMPARE_OP(gt,>)
            case OP_LESS_EQUAL:    LIKELY_INT_COMPARE_OP(le,<=)
            case OP_GREATER_EQUAL: LIKELY_INT_COMPARE_OP(ge,>=)
            case OP_ADD:           LIKELY_INT_BINARY_OP(add)
            case OP_SUBTRACT:      LIKELY_INT_BINARY_OP(sub)
            case OP_MULTIPLY:      BINARY_OP(mul)
            case OP_DIVIDE:        BINARY_OP(truediv)
            case OP_FLOORDIV:      BINARY_OP(floordiv)
            case OP_MODULO:        BINARY_OP(mod)
            case OP_BITOR:         BINARY_OP(or)
            case OP_BITXOR:        BINARY_OP(xor)
            case OP_BITAND:        BINARY_OP(and)
            case OP_SHIFTLEFT:     BINARY_OP(lshift)
            case OP_SHIFTRIGHT:    BINARY_OP(rshift)
            case OP_POW:           BINARY_OP(pow)
            case OP_MATMUL:        BINARY_OP(matmul)
            case OP_EQUAL:         BINARY_OP(eq);
            case OP_IS:            BINARY_OP(is);
            case OP_BITNEGATE:     LIKELY_INT_UNARY_OP(invert,~)
            case OP_NEGATE:        LIKELY_INT_UNARY_OP(neg,-)
            case OP_POS:           LIKELY_INT_UNARY_OP(pos,+)
            case OP_NONE:  krk_push(NONE_VAL()); break;
            case OP_TRUE:  krk_push(BOOLEAN_VAL(1)); break;
            case OP_FALSE: krk_push(BOOLEAN_VAL(0)); break;
            case OP_UNSET: krk_push(KWARGS_VAL(0)); break;
            case OP_NOT:   krk_push(BOOLEAN_VAL(krk_isFalsey(krk_peek(0)))); /* fallthrough */
            case OP_SWAP_POP: krk_swap(1); /* fallthrough */
            case OP_POP:   krk_pop(); break;
 
            case OP_INPLACE_ADD:        INPLACE_BINARY_OP(add)
            case OP_INPLACE_SUBTRACT:   INPLACE_BINARY_OP(sub)
            case OP_INPLACE_MULTIPLY:   INPLACE_BINARY_OP(mul)
            case OP_INPLACE_DIVIDE:     INPLACE_BINARY_OP(truediv)
            case OP_INPLACE_FLOORDIV:   INPLACE_BINARY_OP(floordiv)
            case OP_INPLACE_MODULO:     INPLACE_BINARY_OP(mod)
            case OP_INPLACE_BITOR:      INPLACE_BINARY_OP(or)
            case OP_INPLACE_BITXOR:     INPLACE_BINARY_OP(xor)
            case OP_INPLACE_BITAND:     INPLACE_BINARY_OP(and)
            case OP_INPLACE_SHIFTLEFT:  INPLACE_BINARY_OP(lshift)
            case OP_INPLACE_SHIFTRIGHT: INPLACE_BINARY_OP(rshift)
            case OP_INPLACE_POW:        INPLACE_BINARY_OP(pow)
            case OP_INPLACE_MATMUL:     INPLACE_BINARY_OP(matmul)
 
            case OP_RAISE: {
                krk_raiseException(krk_peek(0), NONE_VAL());
                goto _finishException;
            }
            case OP_RAISE_FROM: {
                krk_raiseException(krk_peek(1), krk_peek(0));
                goto _finishException;
            }
            case OP_CLOSE_UPVALUE:
                closeUpvalues((krk_currentThread.stackTop - krk_currentThread.stack)-1);
                krk_pop();
                break;
            case OP_INVOKE_GETTER: {
                commonMethodInvoke(offsetof(KrkClass,_getter), 2, "'%T' object is not subscriptable");
                break;
            }
            case OP_INVOKE_SETTER: {
                commonMethodInvoke(offsetof(KrkClass,_setter), 3, "'%T' object doesn't support item assignment");
                break;
            }
            case OP_INVOKE_DELETE: {
                commonMethodInvoke(offsetof(KrkClass,_delitem), 2, "'%T' object doesn't support item deletion");
                krk_pop(); /* unused result */
                break;
            }
            case OP_INVOKE_ITER: {
                commonMethodInvoke(offsetof(KrkClass,_iter), 1, "'%T' object is not iterable");
                break;
            }
            case OP_INVOKE_CONTAINS: {
                krk_swap(1); /* operands are backwards */
                commonMethodInvoke(offsetof(KrkClass,_contains), 2, "'%T' object can not be tested for membership");
                break;
            }
            case OP_INVOKE_AWAIT: {
                if (!krk_getAwaitable()) goto _finishException;
                break;
            }
            case OP_SWAP:
                krk_swap(1);
                break;
            case OP_TRY_ELSE: {
                if (IS_HANDLER(krk_peek(0))) {
                    krk_currentThread.stackTop[-1] = HANDLER_VAL(OP_FILTER_EXCEPT,AS_HANDLER_TARGET(krk_peek(0)));
                }
                break;
            }
            case OP_BEGIN_FINALLY: {
                if (IS_HANDLER(krk_peek(0))) {
                    switch (AS_HANDLER_TYPE(krk_peek(0))) {
                        /* We either entered the @c finally without an exception, or the exception was handled by an @c except */
                        case OP_PUSH_TRY:
                        case OP_FILTER_EXCEPT:
                            krk_currentThread.stackTop[-1] = HANDLER_VAL(OP_BEGIN_FINALLY,AS_HANDLER_TARGET(krk_peek(0)));
                            break;
                        /* We entered the @c finally without handling an exception. */
                        case OP_RAISE:
                            krk_currentThread.stackTop[-1] = HANDLER_VAL(OP_END_FINALLY,AS_HANDLER_TARGET(krk_peek(0)));
                            break;
                    }
                }
                break;
            }
            case OP_END_FINALLY: {
                KrkValue handler = krk_peek(0);
                if (IS_HANDLER(handler)) {
                    if (AS_HANDLER_TYPE(handler) == OP_RAISE || AS_HANDLER_TYPE(handler) == OP_END_FINALLY) {
                        krk_pop(); /* handler */
                        krk_currentThread.currentException = krk_pop();
                        krk_currentThread.flags |= KRK_THREAD_HAS_EXCEPTION;
                        goto _finishException;
                    } else if (AS_HANDLER_TYPE(handler) == OP_EXIT_LOOP) {
                        frame->ip = frame->closure->function->chunk.code + AS_HANDLER_TARGET(handler);
                        OPERAND = AS_INTEGER(krk_peek(1));
                        goto _finishPopBlock;
                    } else if (AS_HANDLER_TYPE(handler) == OP_RETURN) {
                        krk_push(krk_peek(1));
                        goto _finishReturn;
                    }
                }
                break;
            }
            case OP_BREAKPOINT: {
#ifndef KRK_DISABLE_DEBUG
                /* First off, halt execution. */
                krk_debugBreakpointHandler();
                if (krk_currentThread.flags & KRK_THREAD_HAS_EXCEPTION) goto _finishException;
                goto _resumeHook;
#else
                krk_runtimeError(vm.exceptions->baseException, "Breakpoint.");
                goto _finishException;
#endif
            }
            case OP_YIELD: {
                KrkValue result = krk_peek(0);
                krk_currentThread.frameCount--;
                assert(krk_currentThread.frameCount == (size_t)krk_currentThread.exitOnFrame);
                /* Do NOT restore the stack */
                return result;
            }
            case OP_ANNOTATE: {
                if (IS_CLOSURE(krk_peek(0))) {
                    krk_swap(1);
                    AS_CLOSURE(krk_peek(1))->annotations = krk_peek(0);
                    krk_pop();
                } else if (IS_NONE(krk_peek(0))) {
                    krk_swap(1);
                    krk_pop();
                } else {
                    krk_runtimeError(vm.exceptions->typeError, "Can not annotate '%T'.", krk_peek(0));
                    goto _finishException;
                }
                break;
            }
 
            case OP_LIST_APPEND_TOP: {
                KrkValue list = krk_peek(1);
                FUNC_NAME(list,append)(2,(KrkValue[]){list,krk_peek(0)},0);
                krk_pop();
                break;
            }
            case OP_DICT_SET_TOP: {
                KrkValue dict = krk_peek(2);
                FUNC_NAME(dict,__setitem__)(3,(KrkValue[]){dict,krk_peek(1),krk_peek(0)},0);
                krk_pop();
                krk_pop();
                break;
            }
            case OP_SET_ADD_TOP: {
                KrkValue set = krk_peek(1);
                FUNC_NAME(set,add)(2,(KrkValue[]){set,krk_peek(0)},0);
                krk_pop();
                break;
            }
 
            case OP_LIST_EXTEND_TOP: {
                KrkValue list = krk_peek(1);
                FUNC_NAME(list,extend)(2,(KrkValue[]){list,krk_peek(0)},0);
                krk_pop();
                break;
            }
            case OP_DICT_UPDATE_TOP: {
                KrkValue dict = krk_peek(1);
                FUNC_NAME(dict,update)(2,(KrkValue[]){dict,krk_peek(0)},0);
                krk_pop();
                break;
            }
            case OP_SET_UPDATE_TOP: {
                KrkValue set = krk_peek(1);
                FUNC_NAME(set,update)(2,(KrkValue[]){set,krk_peek(0)},0);
                krk_pop();
                break;
            }
 
            case OP_TUPLE_FROM_LIST: {
                KrkValue list = krk_peek(0);
                size_t count = AS_LIST(list)->count;
                KrkValue tuple = OBJECT_VAL(krk_newTuple(count));
                krk_push(tuple);
                for (size_t i = 0; i < count; ++i) {
                    AS_TUPLE(tuple)->values.values[AS_TUPLE(tuple)->values.count++] = AS_LIST(list)->values[i];
                }
                krk_swap(1);
                krk_pop();
                break;
            }
 
            case OP_OVERLONG_JUMP: {
                /* Overlong jumps replace 2-byte operand jump instructions with a zero-operand instruction that
                 * slowly scans through a dumb table to find the intended jump target and opcode. */
                for (size_t i = 0; i < frame->closure->function->overlongJumpsCount; ++i) {
                    if (frame->closure->function->overlongJumps[i].instructionOffset ==
                        (size_t)((char*)frame->ip - (char*)frame->closure->function->chunk.code)) {
                        OPERAND = (int)frame->closure->function->overlongJumps[i].intendedTarget << 16;
                        opcode  = frame->closure->function->overlongJumps[i].originalOpcode;
                        goto _switchEntry;
                    }
                }
                krk_runtimeError(vm.exceptions->valueError, "bad jump");
                goto _finishException;
            }
 
            case OP_PUSH_BUILD_CLASS: {
                KrkValue build_class = NONE_VAL();
                krk_tableGet_fast(&vm.builtins->fields, AS_STRING(vm.specialMethodNames[METHOD_BLDCLS]), &build_class);
                krk_push(build_class);
                break;
            }
 
            /*
             * Two-byte operands
             */
            case OP_JUMP_IF_FALSE_OR_POP: {
                TWO_BYTE_OPERAND;
                if (krk_valuesSame(krk_peek(0), BOOLEAN_VAL(0)) || krk_isFalsey(krk_peek(0))) frame->ip += OPERAND;
                else krk_pop();
                break;
            }
            case OP_POP_JUMP_IF_FALSE: {
                TWO_BYTE_OPERAND;
                if (krk_valuesSame(krk_peek(0), BOOLEAN_VAL(0)) || krk_isFalsey(krk_peek(0))) frame->ip += OPERAND;
                krk_pop();
                break;
            }
            case OP_JUMP_IF_TRUE_OR_POP: {
                TWO_BYTE_OPERAND;
                if (!krk_isFalsey(krk_peek(0))) frame->ip += OPERAND;
                else krk_pop();
                break;
            }
            case OP_JUMP: {
                TWO_BYTE_OPERAND;
                frame->ip += OPERAND;
                break;
            }
            case OP_LOOP: {
                TWO_BYTE_OPERAND;
                frame->ip -= OPERAND;
                break;
            }
            case OP_PUSH_TRY: {
                TWO_BYTE_OPERAND;
                uint16_t tryTarget = OPERAND + (frame->ip - frame->closure->function->chunk.code);
                krk_push(NONE_VAL());
                KrkValue handler = HANDLER_VAL(OP_PUSH_TRY, tryTarget);
                krk_push(handler);
                break;
            }
            case OP_PUSH_WITH: {
                TWO_BYTE_OPERAND;
                uint16_t cleanupTarget = OPERAND + (frame->ip - frame->closure->function->chunk.code);
                KrkValue contextManager = krk_peek(0);
                KrkClass * type = krk_getType(contextManager);
                if (unlikely(!type->_enter || !type->_exit)) {
                    if (!type->_enter) krk_runtimeError(vm.exceptions->attributeError, "__enter__");
                    else if (!type->_exit) krk_runtimeError(vm.exceptions->attributeError, "__exit__");
                    goto _finishException;
                }
                krk_push(contextManager);
                krk_callDirect(type->_enter, 1);
                /* Ignore result; don't need to pop */
                krk_push(NONE_VAL());
                KrkValue handler = HANDLER_VAL(OP_PUSH_WITH, cleanupTarget);
                krk_push(handler);
                break;
            }
            case OP_YIELD_FROM: {
                TWO_BYTE_OPERAND;
                uint8_t * exitIp = frame->ip + OPERAND;
                /* Stack has [iterator] [sent value] */
                /* Is this a generator or something with a 'send' method? */
                KrkValue method = krk_valueGetAttribute_default(krk_peek(1), "send", NONE_VAL());
                if (!IS_NONE(method)) {
                    krk_push(method);
                    krk_swap(1);
                    krk_push(krk_callStack(1));
                } else {
                    krk_pop();
                    krk_push(krk_peek(0));
                    krk_push(krk_callStack(0));
                }
                if (!krk_valuesSame(krk_peek(0), krk_peek(1))) {
                    /* Value to yield */
                    break;
                }
 
                krk_pop();
 
                /* Does it have a final value? */
                method = krk_valueGetAttribute_default(krk_peek(0), "__finish__", NONE_VAL());
                if (!IS_NONE(method)) {
                    krk_push(method);
                    krk_swap(1);
                    krk_pop();
                    krk_push(krk_callStack(0));
                } else {
                    krk_pop();
                    krk_push(NONE_VAL());
                }
                frame->ip = exitIp;
                break;
            }
            case OP_CALL_ITER: {
                TWO_BYTE_OPERAND;
                KrkValue iter = krk_peek(0);
                krk_push(iter);
                krk_push(krk_callStack(0));
                /* krk_valuesSame() */
                if (krk_valuesSame(iter, krk_peek(0))) frame->ip += OPERAND;
                break;
            }
            case OP_LOOP_ITER: {
                TWO_BYTE_OPERAND;
                KrkValue iter = krk_peek(0);
                krk_push(iter);
                krk_push(krk_callStack(0));
                if (!krk_valuesSame(iter, krk_peek(0))) frame->ip -= OPERAND;
                break;
            }
            case OP_TEST_ARG: {
                TWO_BYTE_OPERAND;
                if (!krk_valuesSame(krk_pop(), KWARGS_VAL(0))) frame->ip += OPERAND;
                break;
            }
            case OP_FILTER_EXCEPT: {
                TWO_BYTE_OPERAND;
                /* "Pop exception to match with and jump if not a match" */
                int isMatch = 0;
                if (IS_CLASS(krk_peek(0)) && krk_isInstanceOf(krk_peek(2), AS_CLASS(krk_peek(0)))) {
                    isMatch = 1;
                } else if (IS_TUPLE(krk_peek(0))) {
                    for (size_t i = 0; i < AS_TUPLE(krk_peek(0))->values.count; ++i) {
                        if (IS_CLASS(AS_TUPLE(krk_peek(0))->values.values[i]) && krk_isInstanceOf(krk_peek(2), AS_CLASS(AS_TUPLE(krk_peek(0))->values.values[i]))) {
                            isMatch = 1;
                            break;
                        }
                    }
                } else if (IS_NONE(krk_peek(0))) {
                    isMatch = !IS_NONE(krk_peek(2));
                }
                if (isMatch) {
                    /* If exception matched, set handler state. */
                    krk_currentThread.stackTop[-2] = HANDLER_VAL(OP_FILTER_EXCEPT,AS_HANDLER_TARGET(krk_peek(1)));
                } else {
                    /* If exception did not match, jump to next 'except' or 'finally' */
                    frame->ip += OPERAND;
                }
                krk_pop();
                break;
            }
            case OP_ENTER_EXCEPT: {
                TWO_BYTE_OPERAND;
                switch (AS_HANDLER_TYPE(krk_peek(0))) {
                    case OP_RETURN:
                    case OP_END_FINALLY:
                    case OP_EXIT_LOOP:
                        frame->ip += OPERAND;
                        break;
                    case OP_RAISE_FROM:
                        /* Exception happened while in @c finally */
                        krk_pop(); /* handler */
                        krk_currentThread.currentException = krk_pop();
                        krk_currentThread.flags |= KRK_THREAD_HAS_EXCEPTION;
                        goto _finishException;
                }
                break;
            }
 
            case OP_CONSTANT_LONG:
                THREE_BYTE_OPERAND;
            case OP_CONSTANT: {
                ONE_BYTE_OPERAND;
                KrkValue constant = frame->closure->function->chunk.constants.values[OPERAND];
                krk_push(constant);
                break;
            }
            case OP_DEFINE_GLOBAL_LONG:
                THREE_BYTE_OPERAND;
            case OP_DEFINE_GLOBAL: {
                ONE_BYTE_OPERAND;
                KrkString * name = READ_STRING(OPERAND);
                krk_tableSet(frame->globals, OBJECT_VAL(name), krk_peek(0));
                krk_pop();
                break;
            }
            case OP_GET_GLOBAL_LONG:
                THREE_BYTE_OPERAND;
            case OP_GET_GLOBAL: {
                ONE_BYTE_OPERAND;
                KrkString * name = READ_STRING(OPERAND);
                KrkValue value;
                if (!krk_tableGet_fast(frame->globals, name, &value)) {
                    if (!krk_tableGet_fast(&vm.builtins->fields, name, &value)) {
                        krk_runtimeError(vm.exceptions->nameError, "Undefined variable '%S'.", name);
                        goto _finishException;
                    }
                }
                krk_push(value);
                break;
            }
            case OP_SET_GLOBAL_LONG:
                THREE_BYTE_OPERAND;
            case OP_SET_GLOBAL: {
                ONE_BYTE_OPERAND;
                KrkString * name = READ_STRING(OPERAND);
                if (!krk_tableSetIfExists(frame->globals, OBJECT_VAL(name), krk_peek(0))) {
                    krk_runtimeError(vm.exceptions->nameError, "Undefined variable '%S'.", name);
                    goto _finishException;
                }
                break;
            }
            case OP_DEL_GLOBAL_LONG:
                THREE_BYTE_OPERAND;
            case OP_DEL_GLOBAL: {
                ONE_BYTE_OPERAND;
                KrkString * name = READ_STRING(OPERAND);
                if (!krk_tableDelete(frame->globals, OBJECT_VAL(name))) {
                    krk_runtimeError(vm.exceptions->nameError, "Undefined variable '%S'.", name);
                    goto _finishException;
                }
                break;
            }
            case OP_IMPORT_LONG:
                THREE_BYTE_OPERAND;
            case OP_IMPORT: {
                ONE_BYTE_OPERAND;
                KrkString * name = READ_STRING(OPERAND);
                if (!krk_doRecursiveModuleLoad(name)) {
                    goto _finishException;
                }
                break;
            }
            case OP_GET_LOCAL_LONG:
                THREE_BYTE_OPERAND;
            case OP_GET_LOCAL: {
                ONE_BYTE_OPERAND;
                krk_push(krk_currentThread.stack[frame->slots + OPERAND]);
                break;
            }
            case OP_SET_LOCAL_LONG:
                THREE_BYTE_OPERAND;
            case OP_SET_LOCAL: {
                ONE_BYTE_OPERAND;
                krk_currentThread.stack[frame->slots + OPERAND] = krk_peek(0);
                break;
            }
            case OP_SET_LOCAL_POP_LONG:
                THREE_BYTE_OPERAND;
            case OP_SET_LOCAL_POP: {
                ONE_BYTE_OPERAND;
                krk_currentThread.stack[frame->slots + OPERAND] = krk_pop();
                break;
            }
            case OP_CALL_LONG:
                THREE_BYTE_OPERAND;
            case OP_CALL: {
                ONE_BYTE_OPERAND;
                if (unlikely(!krk_callValue(krk_peek(OPERAND), OPERAND, 1))) goto _finishException;
                frame = &krk_currentThread.frames[krk_currentThread.frameCount - 1];
                break;
            }
            case OP_CALL_METHOD_LONG:
                THREE_BYTE_OPERAND;
            case OP_CALL_METHOD: {
                ONE_BYTE_OPERAND;
                if (IS_NONE(krk_peek(OPERAND+1))) {
                    if (unlikely(!krk_callValue(krk_peek(OPERAND), OPERAND, 2))) goto _finishException;
                } else {
                    if (unlikely(!krk_callValue(krk_peek(OPERAND+1), OPERAND+1, 1))) goto _finishException;
                }
                frame = &krk_currentThread.frames[krk_currentThread.frameCount - 1];
                break;
            }
            case OP_EXPAND_ARGS_LONG:
                THREE_BYTE_OPERAND;
            case OP_EXPAND_ARGS: {
                ONE_BYTE_OPERAND;
                krk_push(KWARGS_VAL(KWARGS_SINGLE-OPERAND));
                break;
            }
            case OP_CLOSURE_LONG:
                THREE_BYTE_OPERAND;
            case OP_CLOSURE: {
                ONE_BYTE_OPERAND;
                KrkCodeObject * function = AS_codeobject(READ_CONSTANT(OPERAND));
                KrkClosure * closure = krk_newClosure(function, frame->globalsOwner);
                krk_push(OBJECT_VAL(closure));
                for (size_t i = 0; i < closure->upvalueCount; ++i) {
                    int isLocal = READ_BYTE();
                    int index = READ_BYTE();
                    if (isLocal & 2) {
                        index = (index << 16) | (frame->ip[0] << 8) | (frame->ip[1]);
                        frame->ip += 2;
                    }
                    if (isLocal & 1) {
                        closure->upvalues[i] = captureUpvalue(frame->slots + index);
                    } else if (isLocal & 4) {
                        closure->upvalues[i] = krk_newUpvalue(0);
                        closure->upvalues[i]->closed = NONE_VAL();
                        closure->upvalues[i]->location = -1;
                    } else {
                        closure->upvalues[i] = frame->closure->upvalues[index];
                    }
                }
                break;
            }
            case OP_GET_UPVALUE_LONG:
                THREE_BYTE_OPERAND;
            case OP_GET_UPVALUE: {
                ONE_BYTE_OPERAND;
                krk_push(*UPVALUE_LOCATION(frame->closure->upvalues[OPERAND]));
                break;
            }
            case OP_SET_UPVALUE_LONG:
                THREE_BYTE_OPERAND;
            case OP_SET_UPVALUE: {
                ONE_BYTE_OPERAND;
                *UPVALUE_LOCATION(frame->closure->upvalues[OPERAND]) = krk_peek(0);
                break;
            }
            case OP_IMPORT_FROM_LONG:
                THREE_BYTE_OPERAND;
            case OP_IMPORT_FROM: {
                ONE_BYTE_OPERAND;
                KrkString * name = READ_STRING(OPERAND);
                if (unlikely(!valueGetProperty(name))) {
                    /* Try to import... */
                    KrkValue moduleName;
                    if (!krk_tableGet(&AS_INSTANCE(krk_peek(0))->fields, vm.specialMethodNames[METHOD_NAME], &moduleName)) {
                        krk_runtimeError(vm.exceptions->importError, "Can not import '%S' from non-module '%T' object", name, krk_peek(0));
                        goto _finishException;
                    }
                    krk_push(moduleName);
                    krk_push(OBJECT_VAL(S(".")));
                    krk_addObjects();
                    krk_push(OBJECT_VAL(name));
                    krk_addObjects();
                    if (!krk_doRecursiveModuleLoad(AS_STRING(krk_peek(0)))) {
                        krk_currentThread.flags &= ~KRK_THREAD_HAS_EXCEPTION;
                        krk_runtimeError(vm.exceptions->importError, "Can not import '%S' from '%S'", name, AS_STRING(moduleName));
                        goto _finishException;
                    }
                    krk_currentThread.stackTop[-3] = krk_currentThread.stackTop[-1];
                    krk_currentThread.stackTop -= 2;
                }
            } break;
            case OP_GET_PROPERTY_LONG:
                THREE_BYTE_OPERAND;
            case OP_GET_PROPERTY: {
                ONE_BYTE_OPERAND;
                KrkString * name = READ_STRING(OPERAND);
                if (unlikely(!valueGetProperty(name))) {
                    krk_runtimeError(vm.exceptions->attributeError, "'%T' object has no attribute '%S'", krk_peek(0), name);
                    goto _finishException;
                }
                break;
            }
            case OP_DEL_PROPERTY_LONG:
                THREE_BYTE_OPERAND;
            case OP_DEL_PROPERTY: {
                ONE_BYTE_OPERAND;
                KrkString * name = READ_STRING(OPERAND);
                if (unlikely(!valueDelProperty(name))) {
                    krk_runtimeError(vm.exceptions->attributeError, "'%T' object has no attribute '%S'", krk_peek(0), name);
                    goto _finishException;
                }
                break;
            }
            case OP_SET_PROPERTY_LONG:
                THREE_BYTE_OPERAND;
            case OP_SET_PROPERTY: {
                ONE_BYTE_OPERAND;
                KrkString * name = READ_STRING(OPERAND);
                if (unlikely(!valueSetProperty(name))) {
                    krk_runtimeError(vm.exceptions->attributeError, "'%T' object has no attribute '%S'", krk_peek(1), name);
                    goto _finishException;
                }
                break;
            }
            case OP_SET_NAME_LONG:
                THREE_BYTE_OPERAND;
            case OP_SET_NAME: {
                ONE_BYTE_OPERAND;
                krk_push(krk_currentThread.stack[frame->slots]);
                krk_swap(1);
                krk_push(OBJECT_VAL(READ_STRING(OPERAND)));
                krk_swap(1);
                commonMethodInvoke(offsetof(KrkClass,_setter), 3, "'%T' object doesn't support item assignment");
                break;
            }
            case OP_GET_NAME_LONG:
                THREE_BYTE_OPERAND;
            case OP_GET_NAME: {
                ONE_BYTE_OPERAND;
                krk_push(krk_currentThread.stack[frame->slots]);
                krk_push(OBJECT_VAL(READ_STRING(OPERAND)));
                commonMethodInvoke(offsetof(KrkClass,_getter), 2, "'%T' object doesn't support item assignment");
                break;
            }
            case OP_GET_SUPER_LONG:
                THREE_BYTE_OPERAND;
            case OP_GET_SUPER: {
                ONE_BYTE_OPERAND;
                KrkString * name = READ_STRING(OPERAND);
                KrkValue baseClass = krk_peek(1);
                if (!IS_CLASS(baseClass)) {
                    krk_runtimeError(vm.exceptions->typeError,
                        "super() argument 1 must be class, not %T", baseClass);
                    goto _finishException;
                }
                if (IS_KWARGS(krk_peek(0))) {
                    krk_runtimeError(vm.exceptions->notImplementedError,
                        "Unbound super() reference not supported");
                    goto _finishException;
                }
 
                KrkClass * obj_type;
                KrkValue obj = krk_peek(0);
 
                if (IS_CLASS(obj) && krk_isSubClass(AS_CLASS(obj),AS_CLASS(baseClass))) {
                    /* Class method call */
                    obj_type = AS_CLASS(obj);
                    krk_pop();
                    krk_push(NONE_VAL());
                } else {
                    obj_type = krk_getType(obj);
                    if (!krk_isInstanceOf(krk_peek(0), AS_CLASS(baseClass))) {
                        krk_runtimeError(vm.exceptions->typeError,
                            "'%T' object is not an instance of '%S'",
                            krk_peek(0), AS_CLASS(baseClass)->name);
                        goto _finishException;
                    }
                }
                KrkClass * superclass = AS_CLASS(baseClass)->base ? AS_CLASS(baseClass)->base : vm.baseClasses->objectClass;
                if (!krk_bindMethodSuper(superclass, name, obj_type)) {
                    krk_runtimeError(vm.exceptions->attributeError, "'%S' object has no attribute '%S'",
                        superclass->name, name);
                    goto _finishException;
                }
                /* Swap bind and superclass */
                krk_swap(1);
                /* Pop super class */
                krk_pop();
                break;
            }
            case OP_GET_METHOD_LONG:
                THREE_BYTE_OPERAND;
            case OP_GET_METHOD: {
                ONE_BYTE_OPERAND;
                KrkString * name = READ_STRING(OPERAND);
                int result = valueGetMethod(name);
                if (result == 2) {
                    krk_push(NONE_VAL());
                    krk_swap(2);
                    krk_pop();
                } else if (unlikely(!result)) {
                    krk_runtimeError(vm.exceptions->attributeError, "'%T' object has no attribute '%S'", krk_peek(0), name);
                    goto _finishException;
                } else {
                    krk_swap(1); /* unbound-method object */
                }
                break;
            }
            case OP_DUP_LONG:
                THREE_BYTE_OPERAND;
            case OP_DUP:
                ONE_BYTE_OPERAND;
                krk_push(krk_peek(OPERAND));
                break;
            case OP_KWARGS_LONG:
                THREE_BYTE_OPERAND;
            case OP_KWARGS: {
                ONE_BYTE_OPERAND;
                krk_push(KWARGS_VAL(OPERAND));
                break;
            }
            case OP_CLOSE_MANY_LONG:
                THREE_BYTE_OPERAND;
            case OP_CLOSE_MANY: {
                ONE_BYTE_OPERAND;
                closeUpvalues((krk_currentThread.stackTop - krk_currentThread.stack) - OPERAND);
                for (unsigned int i = 0; i < OPERAND; ++i) {
                    krk_pop();
                }
                break;
            }
 
            case OP_EXIT_LOOP_LONG:
                THREE_BYTE_OPERAND;
            case OP_EXIT_LOOP: {
                ONE_BYTE_OPERAND;
_finishPopBlock: (void)0;
                int stackOffset;
                for (stackOffset = (int)(krk_currentThread.stackTop - krk_currentThread.stack - 1);
                    stackOffset >= (int)(frame->slots + OPERAND) && 
                    !IS_HANDLER_TYPE(krk_currentThread.stack[stackOffset],OP_PUSH_TRY) &&
                    !IS_HANDLER_TYPE(krk_currentThread.stack[stackOffset],OP_PUSH_WITH) &&
                    !IS_HANDLER_TYPE(krk_currentThread.stack[stackOffset],OP_FILTER_EXCEPT)
                    ; stackOffset--) krk_pop();
 
                /* Do the handler. */
                if (stackOffset >= (int)(frame->slots + OPERAND)) {
                    closeUpvalues(stackOffset);
                    uint16_t popTarget = (frame->ip - frame->closure->function->chunk.code);
                    krk_currentThread.stackTop = &krk_currentThread.stack[stackOffset + 1];
                    frame->ip = frame->closure->function->chunk.code + AS_HANDLER_TARGET(krk_peek(0));
                    krk_currentThread.stackTop[-1] = HANDLER_VAL(OP_EXIT_LOOP, popTarget);
                    krk_currentThread.stackTop[-2] = INTEGER_VAL(OPERAND);
                } else {
                    closeUpvalues(frame->slots + OPERAND);
                }
 
                /* Continue normally */
                break;
            }
 
            case OP_POP_MANY_LONG:
                THREE_BYTE_OPERAND;
            case OP_POP_MANY: {
                ONE_BYTE_OPERAND;
                for (unsigned int i = 0; i < OPERAND; ++i) {
                    krk_pop();
                }
                break;
            }
            case OP_TUPLE_LONG:
                THREE_BYTE_OPERAND;
            case OP_TUPLE: {
                ONE_BYTE_OPERAND;
                makeCollection(krk_tuple_of, OPERAND);
                break;
            }
            case OP_MAKE_LIST_LONG:
                THREE_BYTE_OPERAND;
            case OP_MAKE_LIST: {
                ONE_BYTE_OPERAND;
                makeCollection(krk_list_of, OPERAND);
                break;
            }
            case OP_MAKE_DICT_LONG:
                THREE_BYTE_OPERAND;
            case OP_MAKE_DICT: {
                ONE_BYTE_OPERAND;
                makeCollection(krk_dict_of, OPERAND);
                break;
            }
            case OP_MAKE_SET_LONG:
                THREE_BYTE_OPERAND;
            case OP_MAKE_SET: {
                ONE_BYTE_OPERAND;
                makeCollection(krk_set_of, OPERAND);
                break;
            }
            case OP_SLICE_LONG:
                THREE_BYTE_OPERAND;
            case OP_SLICE: {
                ONE_BYTE_OPERAND;
                makeCollection(krk_slice_of, OPERAND);
                break;
            }
            case OP_LIST_APPEND_LONG:
                THREE_BYTE_OPERAND;
            case OP_LIST_APPEND: {
                ONE_BYTE_OPERAND;
                KrkValue list = krk_currentThread.stack[frame->slots + OPERAND];
                FUNC_NAME(list,append)(2,(KrkValue[]){list,krk_peek(0)},0);
                krk_pop();
                break;
            }
            case OP_DICT_SET_LONG:
                THREE_BYTE_OPERAND;
            case OP_DICT_SET: {
                ONE_BYTE_OPERAND;
                KrkValue dict = krk_currentThread.stack[frame->slots + OPERAND];
                FUNC_NAME(dict,__setitem__)(3,(KrkValue[]){dict,krk_peek(1),krk_peek(0)},0);
                krk_pop();
                krk_pop();
                break;
            }
            case OP_SET_ADD_LONG:
                THREE_BYTE_OPERAND;
            case OP_SET_ADD: {
                ONE_BYTE_OPERAND;
                KrkValue set = krk_currentThread.stack[frame->slots + OPERAND];
                FUNC_NAME(set,add)(2,(KrkValue[]){set,krk_peek(0)},0);
                krk_pop();
                break;
            }
            case OP_REVERSE_LONG:
                THREE_BYTE_OPERAND;
            case OP_REVERSE: {
                ONE_BYTE_OPERAND;
                krk_push(NONE_VAL()); /* Storage space */
                for (ssize_t i = 0; i < (ssize_t)OPERAND / 2; ++i) {
                    krk_currentThread.stackTop[-1] = krk_currentThread.stackTop[-i-2];
                    krk_currentThread.stackTop[-i-2] = krk_currentThread.stackTop[-(OPERAND-i)-1];
                    krk_currentThread.stackTop[-(OPERAND-i)-1] = krk_currentThread.stackTop[-1];
                }
                krk_pop();
                break;
            }
            case OP_UNPACK_LONG:
                THREE_BYTE_OPERAND;
            case OP_UNPACK: {
                ONE_BYTE_OPERAND;
                KrkValue sequence = krk_peek(0);
                KrkTuple * values = krk_newTuple(OPERAND);
                krk_push(OBJECT_VAL(values));
                if (unlikely(krk_unpackIterable(sequence, values, _unpack_op))) {
                    goto _finishException;
                }
                if (unlikely(values->values.count != OPERAND)) {
                    krk_runtimeError(vm.exceptions->valueError, "not enough values to unpack (expected %u, got %zu)", OPERAND, values->values.count);
                    goto _finishException;
                }
                if (unlikely(OPERAND == 0)) {
                    krk_pop();
                    krk_pop();
                    break;
                }
                /* We no longer need the sequence */
                krk_swap(1);
                krk_pop();
                for (size_t i = 1; i < values->values.count; ++i) {
                    krk_push(values->values.values[i]);
                }
                krk_currentThread.stackTop[-(ssize_t)OPERAND] = values->values.values[0];
                break;
            }
 
            case OP_FORMAT_VALUE_LONG:
                THREE_BYTE_OPERAND;
            case OP_FORMAT_VALUE: {
                ONE_BYTE_OPERAND;
                if (doFormatString(OPERAND)) goto _finishException;
                break;
            }
 
            case OP_MAKE_STRING_LONG:
                THREE_BYTE_OPERAND;
            case OP_MAKE_STRING: {
                ONE_BYTE_OPERAND;
 
                struct StringBuilder sb = {0};
 
                for (ssize_t i = 0; i < (ssize_t)OPERAND; ++i) {
                    KrkValue s = krk_currentThread.stackTop[-(ssize_t)OPERAND+i];
                    if (unlikely(!IS_STRING(s))) {
                        discardStringBuilder(&sb);
                        krk_runtimeError(vm.exceptions->valueError, "'%T' is not a string", s);
                        goto _finishException;
                    }
                    pushStringBuilderStr(&sb, (char*)AS_STRING(s)->chars, AS_STRING(s)->length);
                }
 
                for (ssize_t i = 0; i < (ssize_t)OPERAND; ++i) {
                    krk_pop();
                }
 
                krk_push(finishStringBuilder(&sb));
                break;
            }
 
            case OP_MISSING_KW_LONG:
                THREE_BYTE_OPERAND;
            case OP_MISSING_KW: {
                ONE_BYTE_OPERAND;
                krk_runtimeError(vm.exceptions->typeError, "%s() missing required keyword-only argument: %R",
                    frame->closure->function->name ? frame->closure->function->name->chars : "<unnamed>",
                    frame->closure->function->keywordArgNames.values[OPERAND]);
                break;
            }
 
            case OP_UNPACK_EX_LONG:
                THREE_BYTE_OPERAND;
            case OP_UNPACK_EX: {
                ONE_BYTE_OPERAND;
                unsigned char before = OPERAND >> 8;
                unsigned char after = OPERAND;
 
                KrkValue sequence = krk_peek(0);
                KrkTuple * values = krk_newTuple(before + after + 1);
                krk_push(OBJECT_VAL(values));
                KrkValue list = krk_list_of(0,NULL,0);
                krk_push(list);
 
 
                struct ex_unpack _context = { values, before, after, list, 0 };
                if (unlikely(krk_unpackIterable(sequence, &_context, _unpack_ex))) {
                    goto _finishException;
                }
 
                if (values->values.count < before) {
                    krk_runtimeError(vm.exceptions->typeError, "not enough values to unpack (expected at least %u, got %zu)",
                        before+after, values->values.count);
                    goto _finishException;
                }
 
                if (values->values.count == before) {
                    values->values.values[values->values.count++] = list;
                }
 
                if (AS_LIST(list)->count < after) {
                    krk_runtimeError(vm.exceptions->typeError, "not enough values to unpack (expected at least %u, got %zu)",
                        before+after, values->values.count - 1 + AS_LIST(list)->count);
                    goto _finishException;
                }
 
                if (after) {
                    size_t more = after;
                    while (more) {
                        values->values.values[before+more] = AS_LIST(list)->values[--AS_LIST(list)->count];
                        more--;
                    }
                    values->values.count += after;
                }
 
                /* We no longer need the sequence */
                krk_pop(); /* list */
                krk_swap(1);
                krk_pop();
                for (size_t i = 1; i < values->values.count; ++i) {
                    krk_push(values->values.values[i]);
                }
                krk_currentThread.stackTop[-(ssize_t)(before + after + 1)] = values->values.values[0];
                break;
            }
 
 
            default:
                __builtin_unreachable();
        }
        if (unlikely(krk_currentThread.flags & KRK_THREAD_HAS_EXCEPTION)) {
_finishException:
            if (!handleException()) {
                if (!IS_NONE(krk_currentThread.stackTop[-2])) {
                    krk_attachInnerException(krk_currentThread.stackTop[-2]);
                }
                frame = &krk_currentThread.frames[krk_currentThread.frameCount - 1];
                frame->ip = frame->closure->function->chunk.code + AS_HANDLER_TARGET(krk_peek(0));
                /* Stick the exception into the exception slot */
                switch (AS_HANDLER_TYPE(krk_currentThread.stackTop[-1])) {
                    /* An exception happened while handling an exception */
                    case OP_RAISE:
                    case OP_FILTER_EXCEPT:
                        krk_currentThread.stackTop[-1] = HANDLER_VAL(OP_END_FINALLY,AS_HANDLER_TARGET(krk_peek(0)));
                        break;
                    /* An exception happened while already in the @c finally block from handling
                     * another exception. Bail. */
                    case OP_END_FINALLY:
                        krk_currentThread.stackTop[-1] = HANDLER_VAL(OP_RAISE_FROM,AS_HANDLER_TARGET(krk_peek(0)));
                        break;
                    /* First exception in this chain. */
                    default:
                        krk_currentThread.stackTop[-1] = HANDLER_VAL(OP_RAISE,AS_HANDLER_TARGET(krk_peek(0)));
                        break;
                }
                krk_currentThread.stackTop[-2] = krk_currentThread.currentException;
                krk_currentThread.currentException = NONE_VAL();
            } else {
                return NONE_VAL();
            }
        }
    }
#undef BINARY_OP
#undef READ_BYTE
}
 
KrkValue krk_runNext(void) {
    size_t oldExit = krk_currentThread.exitOnFrame;
    krk_currentThread.exitOnFrame = krk_currentThread.frameCount - 1;
    KrkValue result = run();
    krk_currentThread.exitOnFrame = oldExit;
    return result;
}
 
KrkInstance * krk_startModule(const char * name) {
    KrkInstance * module = krk_newInstance(vm.baseClasses->moduleClass);
    krk_currentThread.module = module;
    krk_attachNamedObject(&vm.modules, name, (KrkObj*)module);
    krk_attachNamedObject(&module->fields, "__builtins__", (KrkObj*)vm.builtins);
    krk_attachNamedObject(&module->fields, "__name__", (KrkObj*)krk_copyString(name,strlen(name)));
    krk_attachNamedValue(&module->fields, "__annotations__", krk_dict_of(0,NULL,0));
    return module;
}
 
KrkValue krk_interpret(const char * src, const char * fromFile) {
    KrkCodeObject * function = krk_compile(src, fromFile);
    if (!function) {
        if (!krk_currentThread.frameCount) handleException();
        return NONE_VAL();
    }
 
    krk_push(OBJECT_VAL(function));
    krk_attachNamedObject(&krk_currentThread.module->fields, "__file__", (KrkObj*)function->chunk.filename);
    KrkClosure * closure = krk_newClosure(function, OBJECT_VAL(krk_currentThread.module));
    krk_pop();
 
    krk_push(OBJECT_VAL(closure));
    return krk_callStack(0);
}
 
#ifndef KRK_NO_FILESYSTEM
KrkValue krk_runfile(const char * fileName, const char * fromFile) {
    FILE * f = fopen(fileName,"r");
    if (!f) {
        fprintf(stderr, "%s: could not open file '%s': %s\n", "kuroko", fileName, strerror(errno));
        return INTEGER_VAL(errno);
    }
 
    fseek(f, 0, SEEK_END);
    size_t size = ftell(f);
    fseek(f, 0, SEEK_SET);
 
    char * buf = malloc(size+1);
    if (fread(buf, 1, size, f) == 0 && size != 0) {
        fprintf(stderr, "%s: could not read file '%s': %s\n", "kuroko", fileName, strerror(errno));
        return INTEGER_VAL(errno);
    }
    fclose(f);
    buf[size] = '\0';
 
    KrkValue result = krk_interpret(buf, fromFile);
    free(buf);
 
    return result;
}
 
#endif