import statement refactored to a builtin function

README.md

@@ -1 +1,35 @@
-# MiniScript
+## MiniScript Language
+
+MiniScript is a simple embeddable, functional, dynamic-typed, bytecode-interpreted, scripting language written in C. It uses the [mark-and-sweep](https://en.wikipedia.org/wiki/Tracing_garbage_collection) method for garbage collection. MiniScript is  is syntactically similar to Ruby. The frontend and expression parsing techniques were written using [Wren Language](https://wren.io/)  and their wonderful book [craftinginterpreters](http://www.craftinginterpreters.com/) as a reference.
+
+### What MiniScript looks like
+
+```ruby
+
+## Find and return the maximum value in the array.
+def get_max(arr)
+  ret = arr[0]
+  for i in 1..arr.length
+    ret = max(ret, arr[i])
+  end
+  return ret
+end
+
+## Return an array where each element returns true with function [fn] and
+## belongs to [arr].
+def filter(arr, fn)
+  ret = []
+  for elem in arr
+    if fn(elem)
+        array_append(ret, elem)
+    end
+  end
+  return ret
+end
+
+array = [42, null, 3.14, "String", 0..10, [100]]
+nums = filter(array, is_num)
+print(get_max(nums))
+
+```
+

src/compiler.c

@@ -87,7 +87,6 @@ typedef enum {
   //TK_XOREQ,      // ^=
 
   // Keywords.
-  TK_IMPORT,     // import
   TK_DEF,        // def
   TK_NATIVE,     // native (C function declaration)
   TK_END,        // end
@@ -146,7 +145,6 @@ typedef struct {
 
 // List of keywords mapped into their identifiers.
 static _Keyword _keywords[] = {
-  { "import",   6, TK_IMPORT },
   { "def",      3, TK_DEF },
   { "native",   6, TK_NATIVE },
   { "end",      3, TK_END },
@@ -719,13 +717,6 @@ typedef struct {
 
   NameDefnType type;
 
-  // Could be found in one of the imported script or in it's imported script
-  // recursively. If true [_extern] will be the script ID.
-  bool is_extern;
-
-  // Extern script's index.
-  int _extern;
-
   // Index in the variable/function buffer/array.
   int index;
 
@@ -740,7 +731,6 @@ static NameSearchResult compilerSearchName(Compiler* compiler,
 
   NameSearchResult result;
   result.type = NAME_NOT_DEFINED;
-  result.is_extern = false;
 
   // Search through builtin functions.
   int index = findBuiltinFunction(name, length);
@@ -781,8 +771,6 @@ static NameSearchResult compilerSearchName(Compiler* compiler,
     return result;
   }
 
-  // TODO: search in imported scripts.
-
   return result;
 }
 
@@ -863,7 +851,6 @@ GrammarRule rules[] = {  // Prefix       Infix             Infix Precedence
   /* TK_DIVEQ      */   NO_RULE, //    exprAssignment,   PREC_ASSIGNMENT
   /* TK_SRIGHT     */ { NULL,          exprBinaryOp,     PREC_BITWISE_SHIFT },
   /* TK_SLEFT      */ { NULL,          exprBinaryOp,     PREC_BITWISE_SHIFT },
-  /* TK_IMPORT     */   NO_RULE,
   /* TK_DEF        */   NO_RULE,
   /* TK_EXTERN     */   NO_RULE,
   /* TK_END        */   NO_RULE,
@@ -967,34 +954,17 @@ static void exprName(Compiler* compiler, bool can_assign) {
     case NAME_GLOBAL_VAR:
       if (can_assign && match(&compiler->parser, TK_EQ)) {
         compileExpression(compiler);
-        if (result.is_extern) {
+        _emitStoreVariable(compiler, result.index, true);
-          emitOpcode(compiler, OP_STORE_GLOBAL_EXT);
+        
-          emitShort(compiler, result._extern);
-          emitShort(compiler, result.index);
-        } else {
-          _emitStoreVariable(compiler, result.index, true);
-        }
       } else {
-        if (result.is_extern) {
+        emitOpcode(compiler, OP_PUSH_GLOBAL);
-          emitOpcode(compiler, OP_PUSH_GLOBAL_EXT);
+        emitShort(compiler, result.index);
-          emitShort(compiler, result._extern);
-          emitShort(compiler, result.index);
-        } else {
-          emitOpcode(compiler, OP_PUSH_GLOBAL);
-          emitShort(compiler, result.index);
-        }
       }
       return;
 
     case NAME_FUNCTION:
-      if (result.is_extern) {
+      emitOpcode(compiler, OP_PUSH_FN);
-        emitOpcode(compiler, OP_PUSH_FN_EXT);
+      emitShort(compiler, result.index);
-        emitShort(compiler, result._extern);
-        emitShort(compiler, result.index);
-      } else {
-        emitOpcode(compiler, OP_PUSH_FN);
-        emitShort(compiler, result.index);
-      }
       return;
 
     case NAME_BUILTIN:
@@ -1329,6 +1299,10 @@ static void compileFunction(Compiler* compiler, bool is_native) {
   
   consume(parser, TK_END, "Expected 'end' after function definition end.");
 
+  emitOpcode(compiler,  OP_PUSH_NULL);
+  emitOpcode(compiler, OP_RETURN);
+  emitOpcode(compiler, OP_END);
+
   compilerExitBlock(compiler); // Parameter depth.
   compiler->function = compiler->script->body;
 }
@@ -1511,9 +1485,6 @@ Script* compileSource(MSVM* vm, const char* path) {
     } else if (match(parser, TK_DEF)) {
       compileFunction(&compiler, false);
 
-    } else if (match(parser, TK_IMPORT)) {
-      // TODO: import statement must be first of all other.
-      TODO;
     } else {
       compileStatement(&compiler);
     }

src/core.c

@@ -13,7 +13,7 @@ typedef struct {
 } _BuiltinFn;
 
 // Count of builtin function +1 for termination.
-#define BUILTIN_COUNT 10
+#define BUILTIN_COUNT 50
 
 // Array of all builtin functions.
 _BuiltinFn builtins[BUILTIN_COUNT];
@@ -47,6 +47,33 @@ Function* getBuiltinFunction(int index) {
   return &builtins[index].fn;
 }
 
+#define FN_IS_PRIMITE_TYPE(name, check)       \
+  void coreIs##name(MSVM* vm) {               \
+    vm->rbp[0] = VAR_BOOL(check(vm->rbp[1])); \
+  }
+
+#define FN_IS_OBJ_TYPE(name, _enum)                     \
+  void coreIs##name(MSVM* vm) {                         \
+    Var arg1 = vm->rbp[1];                              \
+    if (IS_OBJ(arg1) && AS_OBJ(arg1)->type == _enum) {  \
+      vm->rbp[0] = VAR_TRUE;                            \
+    } else {                                            \
+      vm->rbp[0] = VAR_FALSE;                           \
+    }                                                   \
+  }
+
+FN_IS_PRIMITE_TYPE(Null, IS_NULL)
+FN_IS_PRIMITE_TYPE(Bool, IS_BOOL)
+FN_IS_PRIMITE_TYPE(Num,  IS_NUM)
+
+FN_IS_OBJ_TYPE(String, OBJ_STRING)
+FN_IS_OBJ_TYPE(Array,  OBJ_ARRAY)
+FN_IS_OBJ_TYPE(Map,    OBJ_MAP)
+FN_IS_OBJ_TYPE(Range,  OBJ_RANGE)
+FN_IS_OBJ_TYPE(Function,  OBJ_FUNC)
+FN_IS_OBJ_TYPE(Script,  OBJ_SCRIPT)
+FN_IS_OBJ_TYPE(UserObj,  OBJ_USER)
+
 void coreToString(MSVM* vm) {
   Var arg1 = vm->rbp[1];
   vm->rbp[0] = VAR_OBJ(&toString(vm, arg1)->_super);
@@ -66,12 +93,35 @@ void corePrint(MSVM* vm) {
   vm->config.write_fn(vm, "\n");
 }
 
+void coreImport(MSVM* vm) {
+  Var arg1 = vm->rbp[1];
+  if (IS_OBJ(arg1) && AS_OBJ(arg1)->type == OBJ_STRING) {
+    TODO;
+  } else {
+    msSetRuntimeError(vm, "Expected a String argument.");
+  }
+}
+
 void initializeCore(MSVM* vm) {
 
+  int i = 0; //< Iterate through builtins.
+
   // Initialize builtin functions.
-  int i = 0;
+  initializeBuiltinFN(vm, &builtins[i++], "is_null", 1, coreIsNull);
-  initializeBuiltinFN(vm, &builtins[i++], "print",     1, corePrint);
+  initializeBuiltinFN(vm, &builtins[i++], "is_bool", 1, coreIsBool);
+  initializeBuiltinFN(vm, &builtins[i++], "is_num",  1, coreIsNum);
+
+  initializeBuiltinFN(vm, &builtins[i++], "is_string",   1, coreIsString);
+  initializeBuiltinFN(vm, &builtins[i++], "is_array",    1, coreIsArray);
+  initializeBuiltinFN(vm, &builtins[i++], "is_map",      1, coreIsMap);
+  initializeBuiltinFN(vm, &builtins[i++], "is_range",    1, coreIsRange);
+  initializeBuiltinFN(vm, &builtins[i++], "is_function", 1, coreIsFunction);
+  initializeBuiltinFN(vm, &builtins[i++], "is_script",   1, coreIsScript);
+  initializeBuiltinFN(vm, &builtins[i++], "is_userobj",  1, coreIsUserObj);
+
   initializeBuiltinFN(vm, &builtins[i++], "to_string", 1, coreToString);
+  initializeBuiltinFN(vm, &builtins[i++], "print",     1, corePrint);
+  initializeBuiltinFN(vm, &builtins[i++], "import",    1, coreImport);
 
   // Sentinal to mark the end of the array.
   initializeBuiltinFN(vm, &builtins[i], NULL, 0, NULL);
@@ -112,11 +162,12 @@ Var varAdd(MSVM* vm, Var v1, Var v2) {
     return VAR_NULL;
   }
 
-  // TODO: string addition/ array addition etc.
+  TODO; //string addition/ array addition etc.
   return VAR_NULL;
 }
 
 Var varSubtract(MSVM* vm, Var v1, Var v2) {
+  TODO;
   return VAR_NULL;
 }
 
@@ -130,9 +181,16 @@ Var varMultiply(MSVM* vm, Var v1, Var v2) {
     return VAR_NULL;
   }
 
+  TODO;
   return VAR_NULL;
 }
 
 Var varDivide(MSVM* vm, Var v1, Var v2) {
+  TODO;
   return VAR_NULL;
+}
+
+bool varIterate(MSVM* vm, Var seq, Var* iterator, Var* value) {
+  TODO;
+  return false;
 }

src/core.h

@@ -24,5 +24,11 @@ Var varSubtract(MSVM* vm, Var v1, Var v2);
 Var varMultiply(MSVM* vm, Var v1, Var v2);
 Var varDivide(MSVM* vm, Var v1, Var v2);
 
+// Functions //////////////////////////////////////////////////////////////////
+
+// Parameter [iterator] should be VAR_NULL before starting the iteration.
+// If an element is obtained by iteration it'll return true otherwise returns
+// false indicating that the iteration is over.
+bool varIterate(MSVM* vm, Var seq, Var* iterator, Var* value);
 
 #endif // CORE_H

src/opcodes.h

@@ -64,23 +64,11 @@ OPCODE(PUSH_GLOBAL, 2, 1)
 // params: 2 bytes (uint16_t) index.
 OPCODE(STORE_GLOBAL, 2, -1)
 
-// Push imported script's global value on the stack.
-// params: 2 bytes script index and 2 bytes index.
-OPCODE(PUSH_GLOBAL_EXT, 4, 1)
-
-// Pop and store the value to imported script's global.
-// params: 4 bytes script ID and 2 bytes index.
-OPCODE(STORE_GLOBAL_EXT, 6, -1)
-
 // Push the script's function on the stack. It could later be called. But a
 // function can't be stored i.e. can't assign a function with something else.
 // params: 2 bytes index.
 OPCODE(PUSH_FN, 2, 1)
 
-// Push an imported script's function.
-// params: 2 bytes script index and 2 bytes index.
-OPCODE(PUSH_FN_EXT, 4, 1)
-
 // Push a built in function.
 // params: 2 bytes index of the script.
 OPCODE(PUSH_BUILTIN_FN, 2, 1)
@@ -106,22 +94,6 @@ OPCODE(POP, 0, -1)
 //OPCODE(CALL_8, 2, -8)
 OPCODE(CALL, 4, -0) //< Will calculated at compile time.
 
-// A function pointer will be on top of the stack and it'll be called by OP_CALL...
-// and doesn't need to specify opcode for extern or not.
-//
-// Call a function from an imported script.
-// params: 2 bytes script ID and 2 bytes index. _N -> +2 bytes for argc.
-//OPCODE(CALL_EXT_0, 4,  0)
-//OPCODE(CALL_EXT_1, 4, -1)
-//OPCODE(CALL_EXT_2, 4, -2)
-//OPCODE(CALL_EXT_3, 4, -3)
-//OPCODE(CALL_EXT_4, 4, -4)
-//OPCODE(CALL_EXT_5, 4, -5)
-//OPCODE(CALL_EXT_6, 4, -6)
-//OPCODE(CALL_EXT_7, 4, -7)
-//OPCODE(CALL_EXT_8, 4, -8)
-//OPCODE(CALL_EXT_N, 6, -0) //< Will calculated at compile time.
-
 // The address to jump to. It'll set the ip to the address it should jump to
 // and the address is absolute not an offset from ip's current value.
 // param: 2 bytes jump address.

src/var.c

@@ -58,6 +58,14 @@ String* newString(MSVM* vm, const char* text, uint32_t length) {
   return string;
 }
 
+Range* newRange(MSVM* vm, double from, double to) {
+  Range* range = ALLOCATE(vm, Range);
+  varInitObject(&range->_super, vm, OBJ_RANGE);
+  range->from = from;
+  range->to = to;
+  return range;
+}
+
 Script* newScript(MSVM* vm) {
   Script* script = ALLOCATE(vm, Script);
   varInitObject(&script->_super, vm, OBJ_SCRIPT);
@@ -142,13 +150,20 @@ String* toString(MSVM* vm, Var v) {
         return newString(vm, ((String*)obj)->data, ((String*)obj)->length);
         break;
 
-      case OBJ_ARRAY:    TODO;
+      case OBJ_ARRAY:  return newString(vm, "[Array]",   7); // TODO;
-      case OBJ_MAP:      TODO;
+      case OBJ_MAP:    return newString(vm, "[Map]",     5); // TODO;
-      case OBJ_RANGE:    TODO;
+      case OBJ_RANGE:  return newString(vm, "[Range]",   7); // TODO;
-      case OBJ_SCRIPT:   TODO;
+      case OBJ_SCRIPT: return newString(vm, "[Script]",  8); // TODO;
-      case OBJ_FUNC:     TODO;
+      case OBJ_FUNC: {
-      case OBJ_INSTANCE: TODO;
+        const char* name = ((Function*)obj)->name;
-      case OBJ_USER:     TODO;
+        int length = (int)strlen(name); // TODO: Assert length.
+        char buff[TO_STRING_BUFF_SIZE];
+        memcpy(buff, "[func:", 6);
+        memcpy(buff + 6, name, length);
+        buff[6 + length] = ']';
+        return newString(vm, buff, 6 + length + 1);
+      }
+      case OBJ_USER:   return newString(vm, "[UserObj]", 9); // TODO;
         break;
     }
 

src/var.h

@@ -195,7 +195,6 @@ typedef enum /* ObjectType */ {
 
   OBJ_SCRIPT,
   OBJ_FUNC,
-  OBJ_INSTANCE,
 
   OBJ_USER,
 } ObjectType;
@@ -281,6 +280,9 @@ double varToDouble(Var value);
 // Allocate new String object and return String*.
 String* newString(MSVM* vm, const char* text, uint32_t length);
 
+// Allocate new Range object and return Range*.
+Range* newRange(MSVM* vm, double from, double to);
+
 // Allocate new Script object and return Script*.
 Script* newScript(MSVM* vm);
 

src/vm.c

@@ -61,8 +61,7 @@ void vmPopTempRef(MSVM* self) {
 void _printStackTop(MSVM* vm) {
   if (vm->sp != vm->stack) {
     Var v = *(vm->sp - 1);
-    double n = AS_NUM(v);
+    printf("%s\n", toString(vm, v)->data);
-    printf("%f\n", n);
   }
 }
 
@@ -94,7 +93,6 @@ static inline void pushCallFrame(MSVM* vm, Function* fn) {
   frame->ip = fn->fn->opcodes.data;
 }
 
-
 void msSetRuntimeError(MSVM* vm, const char* format, ...) {
   vm->error = newString(vm, "TODO:", 5);
   TODO;
@@ -168,7 +166,7 @@ MSInterpretResult vmRunScript(MSVM* vm, Script* _script) {
   #error "OPCODE" should not be deifined here.
 #endif
 
-#define DEBUG_INSTRUCTION()
+#define DEBUG_INSTRUCTION() //_printStackTop(vm)
 
 #define SWITCH(code)                 \
   L_vm_main_loop:                    \
@@ -231,7 +229,6 @@ MSInterpretResult vmRunScript(MSVM* vm, Script* _script) {
       PUSH(rbp[index]);
       DISPATCH();
     }
-
     OPCODE(PUSH_LOCAL_N):
     {
       int index = READ_SHORT();
@@ -248,8 +245,17 @@ MSInterpretResult vmRunScript(MSVM* vm, Script* _script) {
     OPCODE(STORE_LOCAL_6):
     OPCODE(STORE_LOCAL_7):
     OPCODE(STORE_LOCAL_8):
+    {
+      int index = (int)(instruction - OP_STORE_LOCAL_0);
+      rbp[index] = POP();
+      DISPATCH();
+    }
     OPCODE(STORE_LOCAL_N):
-      TODO;
+    {
+      int index = READ_SHORT();
+      rbp[index] = POP();
+      DISPATCH();
+    }
 
     OPCODE(PUSH_GLOBAL):
     {
@@ -267,10 +273,6 @@ MSInterpretResult vmRunScript(MSVM* vm, Script* _script) {
       DISPATCH();
     }
 
-    OPCODE(PUSH_GLOBAL_EXT):
-    OPCODE(STORE_GLOBAL_EXT):
-      TODO;
-
     OPCODE(PUSH_FN):
     {
       int index = READ_SHORT();
@@ -280,9 +282,6 @@ MSInterpretResult vmRunScript(MSVM* vm, Script* _script) {
       DISPATCH();
     }
 
-    OPCODE(PUSH_FN_EXT) :
-      TODO;
-
     OPCODE(PUSH_BUILTIN_FN):
     {
       Function* fn = getBuiltinFunction(READ_SHORT());
@@ -298,7 +297,6 @@ MSInterpretResult vmRunScript(MSVM* vm, Script* _script) {
     {
       int argc = READ_SHORT();
       Var* callable = vm->sp - argc - 1;
-      vm->rbp = callable; //< Next call frame starts here.
 
       if (IS_OBJ(*callable) && AS_OBJ(*callable)->type == OBJ_FUNC) {
 
@@ -311,8 +309,13 @@ MSInterpretResult vmRunScript(MSVM* vm, Script* _script) {
         // initialized with VAR_NULL as return value.
         *callable = VAR_NULL;
 
+        // Next call frame starts here. (including return value).
+        vm->rbp = callable;
+
         if (fn->is_native) {
           fn->native(vm);
+          // Pop function arguments except for the return value.
+          vm->sp = vm->rbp + 1;
           CHECK_ERROR();
 
         } else {
@@ -330,7 +333,30 @@ MSInterpretResult vmRunScript(MSVM* vm, Script* _script) {
     OPCODE(JUMP):
     OPCODE(JUMP_NOT):
     OPCODE(JUMP_IF_NOT):
+      TODO;
+
     OPCODE(RETURN):
+    {
+      Var ret = POP();
+      vm->frame_count--;
+
+      // If no more call frames. We're done.
+      if (vm->frame_count == 0) {
+        vm->sp = vm->stack;
+        PUSH(ret);
+        return RESULT_SUCCESS;
+      }
+
+      // Set the return value.
+      *(frame->rbp - 1) = ret;
+
+      // Pop the locals and update stack pointer.
+      vm->sp = frame->rbp;
+
+      LOAD_FRAME();
+      DISPATCH();
+    }
+
     OPCODE(GET_ATTRIB):
     OPCODE(SET_ATTRIB):
     OPCODE(GET_SUBSCRIPT):
@@ -370,9 +396,22 @@ MSInterpretResult vmRunScript(MSVM* vm, Script* _script) {
     OPCODE(LTEQ):
     OPCODE(GT):
     OPCODE(GTEQ):
+      TODO;
+
     OPCODE(RANGE):
+    {
+      Var to = POP();
+      Var from = POP();
+      if (!IS_NUM(from) || !IS_NUM(to)) {
+        RUNTIME_ERROR("Range arguments must be number.");
+      }
+      PUSH(VAR_OBJ(newRange(vm, AS_NUM(from), AS_NUM(to))));
+      DISPATCH();
+    }
+
     OPCODE(IN):
     OPCODE(END):
+      TODO;
       break;
 
     default:

test/main.c

@@ -12,13 +12,6 @@
 
 #include <stdlib.h>
 
-// FIXME:
-//#include "../src/common.h"
-//#include "../src/var.h"
-//#include "../src/vm.h"
-//#include "../src/types/gen/string_buffer.h"
-//#include "../src/types/gen/byte_buffer.h"
-
 static const char* opnames[] = {
   #define OPCODE(name, params, stack) #name,
   #include "../src/opcodes.h"