...

include/pocketpy/common/config.h

@@ -50,3 +50,9 @@
 #else
     #define PK_PLATFORM_SEP '/'
 #endif
+
+#ifdef NDEBUG
+    #define PK_DEBUG 0
+#else
+    #define PK_DEBUG 1
+#endif

include/pocketpy/interpreter/frame.h

@@ -36,7 +36,7 @@ typedef struct Frame {
     const Bytecode* ip;
     const CodeObject* co;
     py_GlobalRef module;
-    py_StackRef function;  // a function object or NULL (global scope)
+    bool has_function;     // is p0 a function?
     py_StackRef p0;        // unwinding base
     py_StackRef locals;    // locals base
     UnwindTarget* uw_list;
@@ -44,7 +44,7 @@ typedef struct Frame {
 
 Frame* Frame__new(const CodeObject* co,
                   py_GlobalRef module,
-                  py_StackRef function,
+                  bool has_function,
                   py_StackRef p0,
                   py_StackRef locals);
 void Frame__delete(Frame* self);
@@ -60,6 +60,5 @@ void Frame__prepare_jump_break(Frame* self, ValueStack*, int);
 int Frame__prepare_loop_break(Frame* self, ValueStack*);
 int Frame__exit_block(Frame* self, ValueStack*, int);
 
-void Frame__gc_mark(Frame* self);
 UnwindTarget* Frame__find_unwind_target(Frame* self, int iblock);
 void Frame__set_unwind_target(Frame* self, py_TValue* sp);

include/pocketpy/interpreter/generator.h

@@ -1,10 +1,13 @@
 #pragma once
 
 #include "pocketpy/interpreter/frame.h"
+#include "pocketpy/pocketpy.h"
 
 typedef struct Generator{
     Frame* frame;
     int state;
 } Generator;
 
-void pk_newgenerator(py_Ref out, Frame* frame);
+void pk_newgenerator(py_Ref out, Frame* frame, py_TValue* backup, int backup_length);
+
+void Generator__dtor(Generator* ud);

include/pocketpy/interpreter/modules.h

@@ -4,3 +4,4 @@ void pk__add_module_pkpy();
 void pk__add_module_os();
 void pk__add_module_math();
 void pk__add_module_dis();
+void pk__add_module_random();

include/pocketpy/pocketpy.h

@@ -19,6 +19,8 @@ typedef int16_t py_Type;
 typedef int64_t py_i64;
 typedef double py_f64;
 
+typedef void (*py_Dtor)(void*);
+
 #define PY_RAISE  // mark a function that can raise an exception
 
 typedef struct c11_sv {
@@ -137,7 +139,7 @@ c11_sv py_name2sv(py_Name);
 /// @param base base type.
 /// @param module module where the type is defined. Use `NULL` for built-in types.
 /// @param dtor destructor function. Use `NULL` if not needed.
-py_Type py_newtype(const char* name, py_Type base, const py_GlobalRef module, void (*dtor)(void*));
+py_Type py_newtype(const char* name, py_Type base, const py_GlobalRef module, py_Dtor dtor);
 
 /// Create a new object.
 /// @param out output reference.
@@ -302,7 +304,7 @@ bool py_setitem(py_Ref self, py_Ref key, py_Ref val) PY_RAISE;
 /// Python equivalent to `del self[key]`.
 bool py_delitem(py_Ref self, py_Ref key) PY_RAISE;
 
-/// Perform a binary operation on the stack.
+/// Perform a binary operation.
 /// The result will be set to `py_retval()`.
 /// The stack remains unchanged after the operation.
 bool py_binaryop(py_Ref lhs, py_Ref rhs, py_Name op, py_Name rop) PY_RAISE;
@@ -429,6 +431,14 @@ bool py_isidentical(py_Ref, py_Ref);
 /// The stack remains unchanged after the operation.
 bool py_call(py_Ref f, int argc, py_Ref argv) PY_RAISE;
 
+#if PK_DEBUG
+/// Call a py_CFunction in a safe way.
+/// This function does extra checks to help you debug `py_CFunction`.
+bool py_callcfunc(py_CFunction f, int argc, py_Ref argv) PY_RAISE;
+#else
+#define py_callcfunc(f, argc, argv) f(argc, argv)
+#endif
+
 /// Python equivalent to `str(val)`.
 bool py_str(py_Ref val) PY_RAISE;
 /// Python equivalent to `repr(val)`.
@@ -448,6 +458,7 @@ py_TmpRef py_list_getitem(py_Ref self, int i);
 void py_list_setitem(py_Ref self, int i, py_Ref val);
 void py_list_delitem(py_Ref self, int i);
 int py_list_len(py_Ref self);
+void py_list_swap(py_Ref self, int i, int j);
 void py_list_append(py_Ref self, py_Ref val);
 void py_list_clear(py_Ref self);
 void py_list_insert(py_Ref self, int i, py_Ref val);

src/compiler/compiler.c

@@ -2664,28 +2664,29 @@ static Error* compile_stmt(Compiler* self) {
             Ctx__s_pop(ctx());
             consume_end_stmt();
         } break;
-        // case TK_WITH: {
-        //     check(EXPR(self));  // [ <expr> ]
-        //     Ctx__s_emit_top(ctx());
-        //     Ctx__enter_block(ctx(), CodeBlockType_CONTEXT_MANAGER);
-        //     Expr* as_name = nullptr;
-        //     if(match(TK_AS)) {
-        //         consume(TK_ID);
-        //         as_name = make_expr<NameExpr>(prev().str(), name_scope());
-        //     }
-        //     Ctx__emit_(ctx(), OP_WITH_ENTER, BC_NOARG, prev().line);
-        //     // [ <expr> <expr>.__enter__() ]
-        //     if(as_name) {
-        //         bool ok = as_name->emit_store(ctx());
-        //         delete_expr(as_name);
-        //         if(!ok) return SyntaxError(self, );
-        //     } else {
-        //         Ctx__emit_(ctx(), OP_POP_TOP, BC_NOARG, BC_KEEPLINE);
-        //     }
-        //     check(compile_block_body());
-        //     Ctx__emit_(ctx(), OP_WITH_EXIT, BC_NOARG, prev().line);
-        //     Ctx__exit_block(ctx());
-        // } break;
+        case TK_WITH: {
+            check(EXPR(self));  // [ <expr> ]
+            Ctx__s_emit_top(ctx());
+            Ctx__enter_block(ctx(), CodeBlockType_CONTEXT_MANAGER);
+            NameExpr* as_name = NULL;
+            if(match(TK_AS)) {
+                consume(TK_ID);
+                py_Name name = py_namev(Token__sv(prev()));
+                as_name = NameExpr__new(prev()->line, name, name_scope(self));
+            }
+            Ctx__emit_(ctx(), OP_WITH_ENTER, BC_NOARG, prev()->line);
+            // [ <expr> <expr>.__enter__() ]
+            if(as_name) {
+                bool ok = vtemit_store((Expr*)as_name, ctx());
+                vtdelete((Expr*)as_name);
+                if(!ok) return SyntaxError(self, "invalid syntax");
+            } else {
+                Ctx__emit_(ctx(), OP_POP_TOP, BC_NOARG, BC_KEEPLINE);
+            }
+            check(compile_block_body(self, compile_stmt));
+            Ctx__emit_(ctx(), OP_WITH_EXIT, BC_NOARG, prev()->line);
+            Ctx__exit_block(ctx());
+        } break;
         /*************************************************/
         case TK_EQ: {
             consume(TK_ID);

src/interpreter/ceval.c

@@ -269,7 +269,7 @@ FrameResult VM__run_top_frame(VM* self) {
                 py_Ref magic = py_tpfindmagic(SECOND()->type, __getitem__);
                 if(magic) {
                     if(magic->type == tp_nativefunc) {
-                        if(!magic->_cfunc(2, SECOND())) goto __ERROR;
+                        if(!py_callcfunc(magic->_cfunc, 2, SECOND())) goto __ERROR;
                         POP();
                     } else {
                         INSERT_THIRD();     // [?, a, b]
@@ -285,7 +285,7 @@ FrameResult VM__run_top_frame(VM* self) {
             case OP_STORE_FAST: frame->locals[byte.arg] = POPX(); DISPATCH();
             case OP_STORE_NAME: {
                 py_Name name = byte.arg;
-                if(frame->function) {
+                if(frame->has_function) {
                     py_Ref slot = Frame__f_locals_try_get(frame, name);
                     if(slot != NULL) {
                         *slot = *TOP();  // store in locals if possible
@@ -322,7 +322,7 @@ FrameResult VM__run_top_frame(VM* self) {
                 if(magic) {
                     PUSH(THIRD());  // [val, a, b, val]
                     if(magic->type == tp_nativefunc) {
-                        if(!magic->_cfunc(3, THIRD())) goto __ERROR;
+                        if(!py_callcfunc(magic->_cfunc, 3, THIRD())) goto __ERROR;
                         STACK_SHRINK(4);
                     } else {
                         *FOURTH() = *magic;  // [__selitem__, a, b, val]
@@ -346,7 +346,7 @@ FrameResult VM__run_top_frame(VM* self) {
             }
             case OP_DELETE_NAME: {
                 py_Name name = byte.arg;
-                if(frame->function) {
+                if(frame->has_function) {
                     py_TValue* slot = Frame__f_locals_try_get(frame, name);
                     if(slot) {
                         py_newnil(slot);
@@ -389,7 +389,7 @@ FrameResult VM__run_top_frame(VM* self) {
                 py_Ref magic = py_tpfindmagic(SECOND()->type, __delitem__);
                 if(magic) {
                     if(magic->type == tp_nativefunc) {
-                        if(!magic->_cfunc(2, SECOND())) goto __ERROR;
+                        if(!py_callcfunc(magic->_cfunc, 2, SECOND())) goto __ERROR;
                         STACK_SHRINK(2);
                     } else {
                         INSERT_THIRD();     // [?, a, b]
@@ -533,8 +533,8 @@ FrameResult VM__run_top_frame(VM* self) {
                 py_Ref magic = py_tpfindmagic(SECOND()->type, __contains__);
                 if(magic) {
                     if(magic->type == tp_nativefunc) {
-                        if(!magic->_cfunc(2, SECOND())) goto __ERROR;
-                        POP();
+                        if(!py_callcfunc(magic->_cfunc, 2, SECOND())) goto __ERROR;
+                        STACK_SHRINK(2);
                     } else {
                         INSERT_THIRD();     // [?, b, a]
                         *THIRD() = *magic;  // [__contains__, a, b]
@@ -898,6 +898,28 @@ FrameResult VM__run_top_frame(VM* self) {
                 DISPATCH();
             }
             ///////////
+            case OP_WITH_ENTER: {
+                // [expr]
+                py_push(TOP());
+                if(!py_pushmethod(__enter__)){
+                    TypeError("'%t' object does not support the context manager protocol", TOP()->type);
+                    goto __ERROR;
+                }
+                if(!py_vectorcall(0, 0)) goto __ERROR;
+                PUSH(py_retval());
+                DISPATCH();
+            }
+            case OP_WITH_EXIT: {
+                // [expr]
+                py_push(TOP());
+                if(!py_pushmethod(__exit__)){
+                    TypeError("'%t' object does not support the context manager protocol", TOP()->type);
+                    goto __ERROR;
+                }
+                if(!py_vectorcall(0, 0)) goto __ERROR;
+                DISPATCH();
+            }
+            ///////////
             case OP_TRY_ENTER: {
                 Frame__set_unwind_target(frame, SP());
                 DISPATCH();
@@ -977,7 +999,7 @@ FrameResult VM__run_top_frame(VM* self) {
         py_BaseException__stpush(&self->curr_exception,
                                  frame->co->src,
                                  lineno < 0 ? Frame__lineno(frame) : lineno,
-                                 frame->function ? frame->co->name->data : NULL);
+                                 frame->has_function ? frame->co->name->data : NULL);
 
         int target = Frame__prepare_jump_exception_handler(frame, &self->stack);
         if(target >= 0) {

src/interpreter/frame.c

@@ -37,7 +37,7 @@ void UnwindTarget__delete(UnwindTarget* self) { free(self); }
 
 Frame* Frame__new(const CodeObject* co,
                   py_GlobalRef module,
-                  py_StackRef function,
+                  bool has_function,
                   py_StackRef p0,
                   py_StackRef locals) {
     static_assert(sizeof(Frame) <= kPoolFrameBlockSize, "!(sizeof(Frame) <= kPoolFrameBlockSize)");
@@ -46,7 +46,7 @@ Frame* Frame__new(const CodeObject* co,
     self->ip = (Bytecode*)co->codes.data - 1;
     self->co = co;
     self->module = module;
-    self->function = function;
+    self->has_function = has_function;
     self->p0 = p0;
     self->locals = locals;
     self->uw_list = NULL;
@@ -131,8 +131,8 @@ void Frame__set_unwind_target(Frame* self, py_TValue* sp) {
 }
 
 py_TValue* Frame__f_closure_try_get(Frame* self, py_Name name) {
-    if(self->function == NULL) return NULL;
-    Function* ud = py_touserdata(self->function);
+    if(!self->has_function) return NULL;
+    Function* ud = py_touserdata(self->p0);
     if(ud->closure == NULL) return NULL;
     return NameDict__try_get(ud->closure, name);
 }

src/interpreter/generator.c

@@ -5,11 +5,19 @@
 #include "pocketpy/pocketpy.h"
 #include <stdbool.h>
 
-void pk_newgenerator(py_Ref out, Frame* frame) {
+void pk_newgenerator(py_Ref out, Frame* frame, py_TValue* backup, int backup_length) {
     Generator* ud = py_newobject(out, tp_generator, 1, sizeof(Generator));
     ud->frame = frame;
     ud->state = 0;
-    py_newlist(py_getslot(out, 0));
+    py_Ref tmp = py_getslot(out, 0);
+    py_newlist(tmp);
+    for(int i = 0; i < backup_length; i++) {
+        py_list_append(tmp, &backup[i]);
+    }
+}
+
+void Generator__dtor(Generator* ud) {
+    if(ud->frame) { Frame__delete(ud->frame); }
 }
 
 static bool generator__next__(int argc, py_Ref argv) {
@@ -33,6 +41,7 @@ static bool generator__next__(int argc, py_Ref argv) {
 
     // push frame
     VM__push_frame(vm, ud->frame);
+    ud->frame = NULL;
 
     FrameResult res = VM__run_top_frame(vm);
 
@@ -51,17 +60,19 @@ static bool generator__next__(int argc, py_Ref argv) {
         for(py_StackRef p = ud->frame->p0; p != vm->stack.sp; p++) {
             py_list_append(backup, p);
         }
+        vm->stack.sp = ud->frame->p0;
         vm->top_frame = vm->top_frame->f_back;
         ud->state = 1;
         return true;
     } else {
+        assert(res == RES_RETURN);
         ud->state = 2;
         return StopIteration();
     }
 }
 
 py_Type pk_generator__register() {
-    py_Type type = pk_newtype("generator", tp_object, NULL, NULL, false, true);
+    py_Type type = pk_newtype("generator", tp_object, NULL, (py_Dtor)Generator__dtor, false, true);
 
     py_bindmagic(type, __iter__, pk_wrapper__self);
     py_bindmagic(type, __next__, generator__next__);

src/interpreter/vm.c

@@ -3,6 +3,7 @@
 #include "pocketpy/common/sstream.h"
 #include "pocketpy/common/utils.h"
 #include "pocketpy/interpreter/generator.h"
+#include "pocketpy/interpreter/modules.h"
 #include "pocketpy/objects/base.h"
 #include "pocketpy/common/_generated.h"
 #include "pocketpy/pocketpy.h"
@@ -194,6 +195,7 @@ void VM__ctor(VM* self) {
     pk__add_module_os();
     pk__add_module_math();
     pk__add_module_dis();
+    pk__add_module_random();
 
     // add python builtins
     do {
@@ -427,7 +429,7 @@ FrameResult VM__vectorcall(VM* self, uint16_t argc, uint16_t kwargc, bool opcall
                 memcpy(argv, self->__vectorcall_buffer, co->nlocals * sizeof(py_TValue));
                 // submit the call
                 if(!fn->cfunc) {
-                    VM__push_frame(self, Frame__new(co, &fn->module, p0, p0, argv));
+                    VM__push_frame(self, Frame__new(co, &fn->module, true, p0, argv));
                     return opcall ? RES_CALL : VM__run_top_frame(self);
                 } else {
                     bool ok = fn->cfunc(co->nlocals, argv);
@@ -451,13 +453,13 @@ FrameResult VM__vectorcall(VM* self, uint16_t argc, uint16_t kwargc, bool opcall
                 // initialize local variables to py_NIL
                 memset(p1, 0, (char*)self->stack.sp - (char*)p1);
                 // submit the call
-                VM__push_frame(self, Frame__new(co, &fn->module, p0, p0, argv));
+                VM__push_frame(self, Frame__new(co, &fn->module, true, p0, argv));
                 return opcall ? RES_CALL : VM__run_top_frame(self);
             case FuncType_GENERATOR: {
                 bool ok = prepare_py_call(self->__vectorcall_buffer, argv, p1, kwargc, fn->decl);
                 if(!ok) return RES_ERROR;
-                Frame* frame = Frame__new(co, &fn->module, p0, p0, argv);
-                pk_newgenerator(py_retval(), frame);
+                Frame* frame = Frame__new(co, &fn->module, false, p0, argv);
+                pk_newgenerator(py_retval(), frame, self->__vectorcall_buffer, co->nlocals);
                 self->stack.sp = p0;
                 return RES_RETURN;
             }
@@ -475,7 +477,7 @@ FrameResult VM__vectorcall(VM* self, uint16_t argc, uint16_t kwargc, bool opcall
     }
 
     if(p0->type == tp_nativefunc) {
-        bool ok = p0->_cfunc(p1 - argv, argv);
+        bool ok = py_callcfunc(p0->_cfunc, p1 - argv, argv);
         self->stack.sp = p0;
         return ok ? RES_RETURN : RES_ERROR;
     }
@@ -592,7 +594,7 @@ void ManagedHeap__mark(ManagedHeap* self) {
 }
 
 void pk_print_stack(VM* self, Frame* frame, Bytecode byte) {
-    // return;
+    return;
     if(frame == NULL || py_isnil(&self->main)) return;
 
     py_TValue* sp = self->stack.sp;
@@ -655,6 +657,6 @@ bool pk_wrapper__self(int argc, py_Ref argv) {
     return true;
 }
 
-bool pk_wrapper__NotImplementedError(int argc, py_Ref argv){
+bool pk_wrapper__NotImplementedError(int argc, py_Ref argv) {
     return py_exception(tp_NotImplementedError, "");
 }

src/modules/os.c

@@ -32,6 +32,7 @@ static bool os_chdir(int argc, py_Ref argv) {
     const char* path = py_tostr(py_arg(0));
     int code = platform_chdir(path);
     if(code != 0) return py_exception(tp_OSError, "chdir() failed: %d", code);
+    py_newnone(py_retval());
     return true;
 }
 

src/modules/random.c

@@ -0,0 +1,302 @@
+#include "pocketpy/interpreter/vm.h"
+#include "pocketpy/pocketpy.h"
+#include <time.h>
+
+/* https://github.com/clibs/mt19937ar
+
+Copyright (c) 2011 Mutsuo Saito, Makoto Matsumoto, Hiroshima
+University and The University of Tokyo. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+    * Redistributions in binary form must reproduce the above
+      copyright notice, this list of conditions and the following
+      disclaimer in the documentation and/or other materials provided
+      with the distribution.
+    * Neither the name of the Hiroshima University nor the names of
+      its contributors may be used to endorse or promote products
+      derived from this software without specific prior written
+      permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+/* Period parameters */
+#define N 624
+#define M 397
+#define MATRIX_A 0x9908b0dfUL   /* constant vector a */
+#define UPPER_MASK 0x80000000UL /* most significant w-r bits */
+#define LOWER_MASK 0x7fffffffUL /* least significant r bits */
+
+typedef struct mt19937 {
+    uint32_t mt[N]; /* the array for the state vector  */
+    int mti;        /* mti==N+1 means mt[N] is not initialized */
+} mt19937;
+
+/* initializes mt[N] with a seed */
+static void mt19937__seed(mt19937* self, uint32_t s) {
+    self->mt[0] = s & 0xffffffffUL;
+    for(self->mti = 1; self->mti < N; self->mti++) {
+        self->mt[self->mti] =
+            (1812433253UL * (self->mt[self->mti - 1] ^ (self->mt[self->mti - 1] >> 30)) +
+             self->mti);
+        /* See Knuth TAOCP Vol2. 3rd Ed. P.106 for multiplier. */
+        /* In the previous versions, MSBs of the seed affect   */
+        /* only MSBs of the array mt[].                        */
+        /* 2002/01/09 modified by Makoto Matsumoto             */
+        self->mt[self->mti] &= 0xffffffffUL;
+        /* for >32 bit machines */
+    }
+}
+
+static void mt19937__ctor(mt19937* self) { self->mti = N + 1; }
+
+/* generates a random number on [0,0xffffffff]-interval */
+static uint32_t mt19937__next_uint32(mt19937* self) {
+    uint32_t* mt = self->mt;
+    uint32_t y;
+    static uint32_t mag01[2] = {0x0UL, MATRIX_A};
+    /* mag01[x] = x * MATRIX_A  for x=0,1 */
+
+    if(self->mti >= N) { /* generate N words at one time */
+        int kk;
+
+        if(self->mti == N + 1) { /* if init_genrand() has not been called, */
+            mt19937__seed(self, clock());
+            // seed(5489UL); /* a default initial seed is used */
+        }
+
+        for(kk = 0; kk < N - M; kk++) {
+            y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
+            mt[kk] = mt[kk + M] ^ (y >> 1) ^ mag01[y & 0x1UL];
+        }
+        for(; kk < N - 1; kk++) {
+            y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
+            mt[kk] = mt[kk + (M - N)] ^ (y >> 1) ^ mag01[y & 0x1UL];
+        }
+        y = (mt[N - 1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
+        mt[N - 1] = mt[M - 1] ^ (y >> 1) ^ mag01[y & 0x1UL];
+
+        self->mti = 0;
+    }
+
+    y = mt[self->mti++];
+
+    /* Tempering */
+    y ^= (y >> 11);
+    y ^= (y << 7) & 0x9d2c5680UL;
+    y ^= (y << 15) & 0xefc60000UL;
+    y ^= (y >> 18);
+
+    return y;
+}
+
+static uint64_t mt19937__next_uint64(mt19937* self) {
+    return (uint64_t)mt19937__next_uint32(self) << 32 | mt19937__next_uint32(self);
+}
+
+/* generates a random number on [0,1)-real-interval */
+static float mt19937__random(mt19937* self) {
+    return mt19937__next_uint32(self) * (1.0 / 4294967296.0); /* divided by 2^32 */
+}
+
+static float mt19937__uniform(mt19937* self, float a, float b) {
+    if(a > b) { return b + mt19937__random(self) * (a - b); }
+    return a + mt19937__random(self) * (b - a);
+}
+
+/* generates a random number on [a, b]-interval */
+int64_t mt19937__randint(mt19937* self, int64_t a, int64_t b) {
+    uint64_t delta = b - a + 1;
+    if(delta < 0x80000000UL) {
+        return a + mt19937__next_uint32(self) % delta;
+    } else {
+        return a + mt19937__next_uint64(self) % delta;
+    }
+}
+
+static bool Random__new__(int argc, py_Ref argv) {
+    PY_CHECK_ARGC(1);
+    mt19937* ud = py_newobject(py_retval(), py_totype(argv), 0, sizeof(mt19937));
+    mt19937__ctor(ud);
+    return true;
+}
+
+static bool Random_seed(int argc, py_Ref argv) {
+    PY_CHECK_ARGC(2);
+    PY_CHECK_ARG_TYPE(1, tp_int);
+    mt19937* ud = py_touserdata(py_arg(0));
+    py_i64 seed = py_toint(py_arg(1));
+    mt19937__seed(ud, seed);
+    py_newnone(py_retval());
+    return true;
+}
+
+static bool Random_random(int argc, py_Ref argv) {
+    PY_CHECK_ARGC(1);
+    mt19937* ud = py_touserdata(py_arg(0));
+    py_f64 res = mt19937__random(ud);
+    py_newfloat(py_retval(), res);
+    return true;
+}
+
+static bool Random_uniform(int argc, py_Ref argv) {
+    PY_CHECK_ARGC(3);
+    mt19937* ud = py_touserdata(py_arg(0));
+    py_f64 a, b;
+    if(!py_castfloat(py_arg(1), &a)) return false;
+    if(!py_castfloat(py_arg(2), &b)) return false;
+    py_f64 res = mt19937__uniform(ud, a, b);
+    py_newfloat(py_retval(), res);
+    return true;
+}
+
+static bool Random_shuffle(int argc, py_Ref argv) {
+    PY_CHECK_ARGC(2);
+    PY_CHECK_ARG_TYPE(1, tp_list);
+    mt19937* ud = py_touserdata(py_arg(0));
+    py_Ref L = py_arg(1);
+    int length = py_list_len(L);
+    for(int i = length - 1; i > 0; i--) {
+        int j = mt19937__randint(ud, 0, i);
+        py_list_swap(L, i, j);
+    }
+    py_newnone(py_retval());
+    return true;
+}
+
+static bool Random_randint(int argc, py_Ref argv) {
+    PY_CHECK_ARGC(3);
+    PY_CHECK_ARG_TYPE(1, tp_int);
+    PY_CHECK_ARG_TYPE(2, tp_int);
+    mt19937* ud = py_touserdata(py_arg(0));
+    py_i64 a = py_toint(py_arg(1));
+    py_i64 b = py_toint(py_arg(2));
+    if(a > b) return ValueError("randint(a, b): a must be less than or equal to b");
+    py_i64 res = mt19937__randint(ud, a, b);
+    py_newint(py_retval(), res);
+    return true;
+}
+
+static bool Random_choice(int argc, py_Ref argv) {
+    PY_CHECK_ARGC(2);
+    mt19937* ud = py_touserdata(py_arg(0));
+    int length;
+    py_TValue* p = pk_arrayview(py_arg(1), &length);
+    if(!p) return TypeError("choice(): argument must be a list or tuple");
+    if(length == 0) return IndexError("cannot choose from an empty sequence");
+    int index = mt19937__randint(ud, 0, length - 1);
+    py_assign(py_retval(), p + index);
+    return true;
+}
+
+static bool Random_choices(int argc, py_Ref argv) {
+    mt19937* ud = py_touserdata(py_arg(0));
+    int length;
+    py_TValue* p = pk_arrayview(py_arg(1), &length);
+    if(!p) return TypeError("choices(): argument must be a list or tuple");
+    if(length == 0) return IndexError("cannot choose from an empty sequence");
+    py_Ref weights = py_arg(2);
+    if(!py_checktype(py_arg(3), tp_int)) return false;
+    py_i64 k = py_toint(py_arg(3));
+
+    py_f64* cum_weights = malloc(sizeof(py_f64) * length);
+    if(py_isnone(weights)) {
+        for(int i = 0; i < length; i++)
+            cum_weights[i] = i + 1;
+    } else {
+        int wlen;
+        py_TValue* w = pk_arrayview(weights, &wlen);
+        if(!w) {
+            free(cum_weights);
+            return TypeError("choices(): weights must be a list or tuple");
+        }
+        if(wlen != length) {
+            free(cum_weights);
+            return ValueError("len(weights) != len(population)");
+        }
+        if(!py_castfloat(&w[0], &cum_weights[0])) {
+            free(cum_weights);
+            return false;
+        }
+        for(int i = 1; i < length; i++) {
+            py_f64 tmp;
+            if(!py_castfloat(&w[i], &tmp)) {
+                free(cum_weights);
+                return false;
+            }
+            cum_weights[i] = cum_weights[i - 1] + tmp;
+        }
+    }
+
+    py_f64 total = cum_weights[length - 1];
+    if(total <= 0) {
+        free(cum_weights);
+        return ValueError("total of weights must be greater than zero");
+    }
+
+    py_newlistn(py_retval(), k);
+    for(int i = 0; i < k; i++) {
+        py_f64 key = mt19937__random(ud) * total;
+        int index;
+        c11__lower_bound(py_f64, cum_weights, length, key, c11__less, &index);
+        assert(index != length);
+        py_list_setitem(py_retval(), i, p + index);
+    }
+
+    free(cum_weights);
+    return true;
+}
+
+void pk__add_module_random() {
+    py_Ref mod = py_newmodule("random");
+    py_Type type = py_newtype("Random", tp_object, mod, NULL);
+
+    py_bindmagic(type, __new__, Random__new__);
+    py_bindmethod(type, "seed", Random_seed);
+    py_bindmethod(type, "random", Random_random);
+    py_bindmethod(type, "uniform", Random_uniform);
+    py_bindmethod(type, "randint", Random_randint);
+    py_bindmethod(type, "shuffle", Random_shuffle);
+    py_bindmethod(type, "choice", Random_choice);
+    py_bind(py_tpobject(type), "choices(self, population, weights=None, k=1)", Random_choices);
+
+    py_Ref inst = py_pushtmp();
+    if(!py_tpcall(type, 0, NULL)) goto __ERROR;
+    py_assign(inst, py_retval());
+
+#define ADD_INST_BOUNDMETHOD(name)                                                                 \
+    if(!py_getattr(inst, py_name(name))) goto __ERROR;                                             \
+    py_setdict(mod, py_name(name), py_retval());
+
+    ADD_INST_BOUNDMETHOD("seed");
+    ADD_INST_BOUNDMETHOD("random");
+    ADD_INST_BOUNDMETHOD("uniform");
+    ADD_INST_BOUNDMETHOD("randint");
+    ADD_INST_BOUNDMETHOD("shuffle");
+    ADD_INST_BOUNDMETHOD("choice");
+    ADD_INST_BOUNDMETHOD("choices");
+
+#undef ADD_INST_BOUNDMETHOD
+
+    py_pop();  // pop inst
+    return;
+
+__ERROR:
+    py_printexc();
+    c11__abort("failed to add module random");
+}

src/public/internal.c

@@ -93,7 +93,7 @@ bool py_exec(const char* source, const char* filename, enum py_CompileMode mode,
 
     if(!module) module = &vm->main;
 
-    Frame* frame = Frame__new(&co, module, NULL, vm->stack.sp, vm->stack.sp);
+    Frame* frame = Frame__new(&co, module, false, vm->stack.sp, vm->stack.sp);
     VM__push_frame(vm, frame);
     FrameResult res = VM__run_top_frame(vm);
     CodeObject__dtor(&co);
@@ -105,7 +105,7 @@ bool py_exec(const char* source, const char* filename, enum py_CompileMode mode,
 
 bool py_call(py_Ref f, int argc, py_Ref argv) {
     if(f->type == tp_nativefunc) {
-        return f->_cfunc(argc, argv);
+        return py_callcfunc(f->_cfunc, argc, argv);
     } else {
         py_push(f);
         py_pushnil();
@@ -115,6 +115,16 @@ bool py_call(py_Ref f, int argc, py_Ref argv) {
     }
 }
 
+bool py_callcfunc(py_CFunction f, int argc, py_Ref argv) {
+    py_StackRef p0 = py_peek(0);
+    py_newnil(py_retval());
+    bool ok = f(argc, argv);
+    if(!ok) return false;
+    if(py_peek(0) != p0) c11__abort("py_CFunction corrupts the stack! Did you forget to call `py_pop()`?");
+    if(py_isnil(py_retval())) c11__abort("py_CFunction returns nothing! Did you forget to call `py_newnone(py_retval())`?");
+    return true;
+}
+
 bool py_vectorcall(uint16_t argc, uint16_t kwargc) {
     VM* vm = pk_current_vm;
     return VM__vectorcall(vm, argc, kwargc, false) != RES_ERROR;

src/public/modules.c

@@ -319,6 +319,7 @@ static bool builtins_setattr(int argc, py_Ref argv) {
     PY_CHECK_ARGC(3);
     PY_CHECK_ARG_TYPE(1, tp_str);
     py_Name name = py_namev(py_tosv(py_arg(1)));
+    py_newnone(py_retval());
     return py_setattr(py_arg(0), name, py_arg(2));
 }
 
@@ -344,6 +345,7 @@ static bool builtins_delattr(int argc, py_Ref argv) {
     PY_CHECK_ARGC(2);
     PY_CHECK_ARG_TYPE(1, tp_str);
     py_Name name = py_namev(py_tosv(py_arg(1)));
+    py_newnone(py_retval());
     return py_delattr(py_arg(0), name);
 }
 
@@ -468,8 +470,8 @@ static bool super__new__(int argc, py_Ref argv) {
     py_Ref self_arg = NULL;
     if(argc == 1) {
         // super()
-        if(frame->function) {
-            Function* func = py_touserdata(frame->function);
+        if(frame->has_function) {
+            Function* func = py_touserdata(frame->p0);
             *class_arg = *(py_Type*)PyObject__userdata(func->clazz);
             if(frame->co->nlocals > 0) self_arg = &frame->locals[0];
         }

src/public/py_dict.c

@@ -211,6 +211,7 @@ static bool dict__new__(int argc, py_Ref argv) {
 }
 
 static bool dict__init__(int argc, py_Ref argv) {
+    py_newnone(py_retval());
     if(argc > 2) return TypeError("dict.__init__() takes at most 2 arguments (%d given)", argc);
     if(argc == 1) return true;
     assert(argc == 2);
@@ -324,6 +325,7 @@ static bool dict__eq__(int argc, py_Ref argv) {
             return true;
         }
     }
+    py_newbool(py_retval(), true);
     return true;
 }
 
@@ -340,6 +342,7 @@ static bool dict_clear(int argc, py_Ref argv) {
     PY_CHECK_ARGC(1);
     Dict* self = py_touserdata(argv);
     Dict__clear(self);
+    py_newnone(py_retval());
     return true;
 }
 
@@ -366,6 +369,7 @@ static bool dict_update(int argc, py_Ref argv) {
         if(py_isnil(&entry->key)) continue;
         if(!Dict__set(self, &entry->key, &entry->val)) return false;
     }
+    py_newnone(py_retval());
     return true;
 }
 

src/public/py_exception.c

@@ -60,7 +60,8 @@ static bool _py_BaseException__new__(int argc, py_Ref argv) {
 }
 
 static bool _py_BaseException__init__(int argc, py_Ref argv) {
-    if(argc == 1 + 0) { return true; }
+    py_newnone(py_retval());
+    if(argc == 1 + 0) return true;
     if(argc == 1 + 1) {
         py_setslot(py_arg(0), 0, py_arg(1));
         return true;
@@ -138,7 +139,7 @@ void py_printexc() {
     free(msg);
 }
 
-static void c11_sbuf__write_exc(c11_sbuf* self, py_Ref exc){
+static void c11_sbuf__write_exc(c11_sbuf* self, py_Ref exc) {
     if(true) { c11_sbuf__write_cstr(self, "Traceback (most recent call last):\n"); }
 
     BaseException* ud = py_touserdata(exc);
@@ -174,7 +175,9 @@ char* py_formatexc() {
         c11_sbuf__write_exc(&ss, &vm->curr_exception);
     } else {
         c11_sbuf__write_exc(&ss, inner);
-        c11_sbuf__write_cstr(&ss, "\n\nDuring handling of the above exception, another exception occurred:\n\n");
+        c11_sbuf__write_cstr(
+            &ss,
+            "\n\nDuring handling of the above exception, another exception occurred:\n\n");
         c11_sbuf__write_exc(&ss, &vm->curr_exception);
     }
 
@@ -207,7 +210,7 @@ bool py_exception(py_Type type, const char* fmt, ...) {
 bool py_raise(py_Ref exc) {
     assert(py_isinstance(exc, tp_BaseException));
     VM* vm = pk_current_vm;
-    if(!py_isnil(&vm->curr_exception)){
+    if(!py_isnil(&vm->curr_exception)) {
         // inner exception
         py_setslot(exc, 1, &vm->curr_exception);
     }

src/public/py_list.c

@@ -44,6 +44,13 @@ int py_list_len(py_Ref self) {
     return userdata->count;
 }
 
+void py_list_swap(py_Ref self, int i, int j){
+    py_TValue* data = py_list_data(self);
+    py_TValue tmp = data[i];
+    data[i] = data[j];
+    data[j] = tmp;
+}
+
 void py_list_append(py_Ref self, py_Ref val) {
     List* userdata = py_touserdata(self);
     c11_vector__push(py_TValue, userdata, *val);
@@ -160,6 +167,7 @@ static bool list__setitem__(int argc, py_Ref argv) {
     int index = py_toint(py_arg(1));
     if(!pk__normalize_index(&index, self->count)) return false;
     c11__setitem(py_TValue, self, index, *py_arg(2));
+    py_newnone(py_retval());
     return true;
 }
 

src/public/py_ops.c

@@ -81,7 +81,9 @@ int py_next(py_Ref val) {
         py_clearexc(p0);
         vm->is_stopiteration = true;
     }
-    return vm->is_stopiteration ? 0 : -1;
+    int retval = vm->is_stopiteration ? 0 : -1;
+    vm->is_stopiteration = false;
+    return retval;
 }
 
 bool py_getattr(py_Ref self, py_Name name) {

src/public/stack_ops.c

@@ -60,8 +60,8 @@ void py_setslot(py_Ref self, int i, py_Ref val) {
 
 py_StackRef py_inspect_currentfunction(){
     Frame* frame = pk_current_vm->top_frame;
-    if(!frame) return NULL;
-    return frame->function;
+    if(!frame || !frame->has_function) return NULL;
+    return frame->p0;
 }
 
 void py_assign(py_Ref dst, py_Ref src) { *dst = *src; }

src/public/values.c

@@ -101,7 +101,7 @@ py_Name
     return py_name(ud->decl->code.name->data);
 }
 
-void py_newboundmethod(py_Ref out, py_Ref self, py_Ref func){
+void py_newboundmethod(py_Ref out, py_Ref self, py_Ref func) {
     py_newobject(out, tp_boundmethod, 2, 0);
     py_setslot(out, 0, self);
     py_setslot(out, 1, func);

tests/51_yield.py

@@ -6,6 +6,12 @@ a = g()
 assert next(a) == 1
 assert next(a) == 2
 
+try:
+    next(a)
+    exit(1)
+except StopIteration:
+    pass
+
 def f(n):
     for i in range(n):
         yield i
@@ -50,7 +56,7 @@ assert a == [1, 2, 3]
 def f():
     for i in range(5):
         yield str(i)
-assert '|'.join(f()) == '0|1|2|3|4'
+assert '|'.join(list(f())) == '0|1|2|3|4'
 
 
 def f(n):

tests/70_random.py

@@ -1,4 +1,4 @@
-import random as r, sys as s
+import random as r
 
 r.seed(10)
 

tests/80_c.py

@@ -1,74 +0,0 @@
-import c
-
-a = c.malloc(100)
-c.free(a)
-
-a = c.malloc(100)
-c.memset(a, 0, 100)
-b = c.malloc(100)
-b = c.memcpy(b, a, 100)
-
-bp = c.p_cast(a, c.int_p)
-
-assert c.p_value(c.NULL) == 0
-assert c.NULL == c.NULL
-assert c.NULL != a
-
-for i in range(10):
-    bp[i] = i
-    assert bp[i] == i
-    (bp+i).write(i)
-    assert (bp+i).read() == i
-
-i = c.float_(10)
-assert i.sizeof() == 4
-j = i.copy()
-assert i == j
-assert i is not j
-
-####################
-
-class Vec2(c.struct):
-    def __new__(cls, x: float, y: float):
-        obj = c.struct.__new__(cls, 8)
-        obj.write_float(x, 0)
-        obj.write_float(y, 4)
-        return obj
-
-    @property
-    def x(self) -> float:
-        return self.read_float(0)
-    
-    @property
-    def y(self) -> float:
-        return self.read_float(4)
-    
-    def __repr__(self) -> str:
-        return f"Vec2({self.x}, {self.y})"
-    
-a = Vec2(1, 2)
-assert isinstance(a, c.struct)
-assert type(a) is Vec2
-assert repr(a) == "Vec2(1.0, 2.0)"
-
-a = c.struct(10)
-p = c.p_cast(a.addr(), c.char_p)
-p.write_string("Hello!")
-assert p[0] == ord("H")
-assert p[1] == ord("e")
-assert p[2] == ord("l")
-assert p[3] == ord("l")
-assert p[4] == ord("o")
-assert p[5] == ord("!")
-assert p[6] == 0
-assert p.read_string() == "Hello!"
-
-s = c.struct(67)
-for i in range(67):
-    s.write_char(i, i)
-
-s_hex = s.hex()
-s_r = c.struct.fromhex(s_hex)
-assert (s == s_r and s is not s_r), (s_hex, s_r.hex())
-assert s_hex == s_r.hex()
-