fixed: iterator (internal) variables popped twise.

printing stack trace implemented

cli/main.c

@@ -10,7 +10,13 @@
 
 void errorPrint(PKVM* vm, PKErrorType type, const char* file, int line,
                 const char* message) {
-  fprintf(stderr, "Error: %s\n\tat %s:%i\n", message, file, line);
+  if (type == PK_ERROR_COMPILE) {
+    fprintf(stderr, "Error: %s\n\tat %s:%i\n", message, file, line);
+  } else if (type == PK_ERROR_RUNTIME) {
+    fprintf(stderr, "Error: %s\n", message);
+  } else if (type == PK_ERROR_STACKTRACE) {
+    fprintf(stderr, "  [%s:%i] %s()\n", file, line, message);
+  }
 }
 
 void writeFunction(PKVM* vm, const char* text) {

docs/static/try_now.js

@@ -1,39 +0,0 @@
-/*
- *  Copyright (c) 2021 Thakee Nathees
- *  Licensed under: MIT License
- */
-
-const _initial_snippet = `\
-# A recursive fibonacci function.
-def fib(n)
-  if n < 2 then return n end
-  return fib(n-1) + fib(n-2)
-end
-
-# Print all fibonacci from 0 to 5 exclusive.
-for i in 0..5
-  print(fib(i))
-end
-`
-
-var highlight_fn = function(editor) {
-	// highlight.js does not trim old tags,
-	// let's do it by this hack.
-	editor.textContent = editor.textContent;
-	editor.innerHTML = Prism.highlight(editor.textContent, Prism.languages.ruby, 'ruby');
-}
-
-var runSource;
-window.onload = function() { // called after index.html is loaded -> Module is defined.
-	runSource = Module.cwrap('runSource', 'number', ['string']);
-	document.getElementById("run-button").onclick = function() {
-		document.getElementById('output').innerText = '';
-		const source = document.querySelector('.editor').textContent;
-		runSource(source);
-	}
-
-	let editor = document.querySelector('.editor')
-	editor.textContent = _initial_snippet;
-	highlight_fn(editor);
-}
-

docs/try/io_api.js

@@ -10,9 +10,19 @@
 mergeInto(LibraryManager.library, {
 	/** js_func_name : function() {...} */
 	
-	js_errorPrint : function(message, line) {
+	js_errorPrint : function(type, line, message) {
+		var err_text = ''
+		const msg = AsciiToString(message);
+		if (type == 0 /*PK_ERROR_COMPILE*/) {
+			err_text = `[Error at:${line}] ${msg}`;
+		} else if (type == 1 /*PK_ERROR_RUNTIME*/) {
+			err_text = `Error: ${msg}`;
+		} else if (type == 2 /*PK_ERROR_STACKTRACE*/) {
+			err_text = `  [at:${line}] ${msg}`;
+		}
+  
 		var out = document.getElementById("output");
-		out.innerText += `[Error at:${line}]: ${AsciiToString(message)} \n`;
+		out.innerText += err_text + '\n';
 	},
 	
 	js_writeFunction : function(message) {

docs/try/main.c

@@ -10,13 +10,15 @@
 #include <emscripten.h>
 #include "pocketlang.h"
 
-extern void js_errorPrint(const char* message, int line);
+extern void js_errorPrint(int type, int line, const char* message);
 extern void js_writeFunction(const char* message);
 extern const char* js_loadScript();
 
 void errorPrint(PKVM* vm, PKErrorType type, const char* file, int line,
                 const char* message) {
-  js_errorPrint(message, line);
+  // No need to pass file (since there is only script that'll ever run on the 
+  // browser.
+  js_errorPrint((int)type, line, message);
 }
 
 void writeFunction(PKVM* vm, const char* text) {

src/compiler.c

@@ -345,6 +345,8 @@ static void reportError(Parser* parser, const char* file, int line,
   int length = vsprintf(message, fmt, args);
   ASSERT(length < ERROR_MESSAGE_SIZE, "Error message buffer should not exceed "
     "the buffer");
+
+  if (vm->config.error_fn == NULL) return;
   vm->config.error_fn(vm, PK_ERROR_COMPILE, file, line, message);
 }
 

src/core.c

@@ -206,6 +206,10 @@ void coreToString(PKVM* vm) {
 }
 
 void corePrint(PKVM* vm) {
+  // If the host appliaction donesn't provide any write function, discard the
+  // output.
+  if (vm->config.write_fn == NULL) return;
+
   String* str; //< Will be cleaned by garbage collector;
 
   for (int i = 1; i <= ARGC; i++) {

src/debug.c

@@ -259,18 +259,18 @@ void dumpInstructions(PKVM* vm, Function* func) {
 }
 
 void reportStackTrace(PKVM* vm) {
+  if (vm->config.error_fn == NULL) return;
+
   Fiber* fiber = vm->fiber;
-  Script* script = fiber->func->owner;
 
-  //vm->config.error_fn(vm, PK_ERROR_RUNTIME, NULL, -1, fiber->error )
+  vm->config.error_fn(vm, PK_ERROR_RUNTIME, NULL, -1, fiber->error->data);
-  //
-  //// TODO: I'm not confident about this approach.
-  //if (script->path != NULL) { // User script.
-  //
-  //
-  //} else { // "std" script.
-  //
-  //}
 
+  for (int i = fiber->frame_count - 1; i >= 0; i--) {
+    CallFrame* frame = &fiber->frames[i];
+    Function* fn = frame->fn;
+    ASSERT(!fn->is_native, OOPS);
+    int line = fn->fn->oplines.data[frame->ip - fn->fn->opcodes.data - 1];
+    vm->config.error_fn(vm, PK_ERROR_STACKTRACE, fn->owner->name->data, line, fn->name);
+  }
 }
 

src/include/pocketlang.h

@@ -83,7 +83,7 @@ typedef void (*pkNativeFn)(PKVM* vm);
 typedef enum {
 
   // Compile time errors (syntax errors, unresolved fn, etc).
-  PK_ERROR_COMPILE,
+  PK_ERROR_COMPILE = 0,
 
   // Runtime error message.
   PK_ERROR_RUNTIME,

src/var.c

@@ -189,6 +189,7 @@ static void blackenObject(Object* obj, PKVM* vm) {
       }
       vm->bytes_allocated += sizeof(CallFrame) * fiber->frame_capacity;
 
+      grayObject(&fiber->caller->_super, vm);
       grayObject(&fiber->error->_super, vm);
 
     } break;
@@ -286,7 +287,7 @@ Script* newScript(PKVM* vm, String* name) {
   stringBufferInit(&script->names);
 
   vmPushTempRef(vm, &script->_super);
-  const char* fn_name = "@(ScriptLevel)";
+  const char* fn_name = "$(SourceBody)";
   script->body = newFunction(vm, fn_name, (int)strlen(fn_name), script, false);
   vmPopTempRef(vm);
 

src/var.h

@@ -336,6 +336,9 @@ struct Fiber {
   // Number of frame entry in frames.
   int frame_count;
 
+  // Caller of this fiber if it has one, NULL otherwise.
+  Fiber* caller;
+
   // Runtime error initially NULL, heap allocated.
   String* error;
 };

src/vm.c

@@ -230,8 +230,9 @@ static Var importScript(PKVM* vm, String* name, bool is_core,
   *is_new_script = true;
 
   pkStringResult result = { false, NULL, NULL };
-  if (vm->config.load_script_fn != NULL)
+  if (vm->config.load_script_fn != NULL) {
     result = vm->config.load_script_fn(vm, name->data);
+  }
 
   if (!result.success) {
     vmPopTempRef(vm); // name
@@ -290,12 +291,15 @@ static inline void pushCallFrame(PKVM* vm, Function* fn) {
 }
 
 void pkSetRuntimeError(PKVM* vm, const char* message) {
-  vm->fiber->error = stringFormat(vm, "$", message);
+  vm->fiber->error = newString(vm, message);
 }
 
 void vmReportError(PKVM* vm) {
   ASSERT(HAS_ERROR(), "runtimeError() should be called after an error.");
-  TODO; // TODO: create debug.h
+
+  // TODO: pass the error to the caller of the fiber.
+
+  reportStackTrace(vm);
 }
 
 // FIXME: temp.
@@ -327,16 +331,20 @@ PKInterpretResult pkInterpret(PKVM* vm, const char* file) {
   vmPushTempRef(vm, &name->_super);
 
   if (!resolveScriptPath(vm, &name)) {
-    vm->config.error_fn(vm, PK_ERROR_COMPILE, NULL, -1,
+    if (vm->config.error_fn != NULL) {
-      stringFormat(vm, "Failed to resolve path '$'.", file)->data);
+      vm->config.error_fn(vm, PK_ERROR_COMPILE, NULL, -1,
+        stringFormat(vm, "Failed to resolve path '$'.", file)->data);
+    }
     return PK_RESULT_COMPILE_ERROR;
   }
 
   // Load the script source.
   pkStringResult res = vm->config.load_script_fn(vm, name->data);
   if (!res.success) {
-    vm->config.error_fn(vm, PK_ERROR_COMPILE, NULL, -1,
+    if (vm->config.error_fn != NULL) {
-      stringFormat(vm, "Failed to load script '@'.", name)->data);
+      vm->config.error_fn(vm, PK_ERROR_COMPILE, NULL, -1,
+        stringFormat(vm, "Failed to load script '@'.", name)->data);
+    }
     return PK_RESULT_COMPILE_ERROR;
   }
 
@@ -390,7 +398,10 @@ void _debugRuntime(PKVM* vm) {
 
 PKInterpretResult vmRunScript(PKVM* vm, Script* _script) {
 
-  register uint8_t* ip;      //< Current instruction pointer.
+  // Reference to the instruction pointer in the call frame.
+  register uint8_t** ip;
+#define IP (*ip) // Convinent macro to the instruction pointer.
+
   register Var* rbp;         //< Stack base pointer register.
   register CallFrame* frame; //< Current call frame.
   register Script* script;   //< Currently executing script.
@@ -420,8 +431,8 @@ PKInterpretResult vmRunScript(PKVM* vm, Script* _script) {
 #define POP()        (*(--vm->fiber->sp))
 #define DROP()       (--vm->fiber->sp)
 #define PEEK()       (*(vm->fiber->sp - 1))
-#define READ_BYTE()  (*ip++)
+#define READ_BYTE()  (*IP++)
-#define READ_SHORT() (ip+=2, (uint16_t)((ip[-2] << 8) | ip[-1]))
+#define READ_SHORT() (IP+=2, (uint16_t)((IP[-2] << 8) | IP[-1]))
 
 // Check if any runtime error exists and if so returns RESULT_RUNTIME_ERROR.
 #define CHECK_ERROR()                 \
@@ -440,16 +451,12 @@ PKInterpretResult vmRunScript(PKVM* vm, Script* _script) {
     return PK_RESULT_RUNTIME_ERROR;            \
   } while (false)
 
-// Store the current frame to vm's call frame before pushing a new frame.
+// Load the last call frame to vm's execution variables to resume/run the
-// Frames rbp will set once it created and will never change.
+// function.
-#define STORE_FRAME() frame->ip = ip
-
-// Update the call frame and ip once vm's call frame pushed or popped.
-// fuction call, return or done running imported script.
 #define LOAD_FRAME()                                       \
   do {                                                     \
     frame = &vm->fiber->frames[vm->fiber->frame_count-1];  \
-    ip = frame->ip;                                        \
+    ip = &(frame->ip);                                     \
     rbp = frame->rbp;                                      \
     script = frame->fn->owner;                             \
   } while (false)
@@ -663,9 +670,8 @@ PKInterpretResult vmRunScript(PKVM* vm, Script* _script) {
           CHECK_ERROR();
 
         } else {
-          STORE_FRAME();
           pushCallFrame(vm, fn);
-          LOAD_FRAME();
+          LOAD_FRAME(); //< Load the top frame to vm's execution variables.
         }
 
       } else {
@@ -681,13 +687,10 @@ PKInterpretResult vmRunScript(PKVM* vm, Script* _script) {
       Var* container  = (vm->fiber->sp - 3);
       uint16_t jump_offset = READ_SHORT();
       
-      bool is_done = varIterate(vm, *container, iterator, iter_value);
+      bool iterated = varIterate(vm, *container, iterator, iter_value);
       CHECK_ERROR();
-      if (!is_done) {
+      if (!iterated) {
-        DROP(); //< Iter value.
+        IP += jump_offset;
-        DROP(); //< Iterator.
-        DROP(); //< Container.
-        ip += jump_offset;
       }
       DISPATCH();
     }
@@ -695,14 +698,14 @@ PKInterpretResult vmRunScript(PKVM* vm, Script* _script) {
     OPCODE(JUMP):
     {
       uint16_t offset = READ_SHORT();
-      ip += offset;
+      IP += offset;
       DISPATCH();
     }
 
     OPCODE(LOOP):
     {
       uint16_t offset = READ_SHORT();
-      ip -= offset;
+      IP -= offset;
       DISPATCH();
     }
 
@@ -712,7 +715,7 @@ PKInterpretResult vmRunScript(PKVM* vm, Script* _script) {
       Var cond = POP();
       uint16_t offset = READ_SHORT();
       if (toBool(cond)) {
-        ip += offset;
+        IP += offset;
       }
       DISPATCH();
     }
@@ -722,14 +725,18 @@ PKInterpretResult vmRunScript(PKVM* vm, Script* _script) {
       Var cond = POP();
       uint16_t offset = READ_SHORT();
       if (!toBool(cond)) {
-        ip += offset;
+        IP += offset;
       }
       DISPATCH();
     }
 
     OPCODE(RETURN):
     {
+      // TODO: handle caller fiber.
+
       Var ret = POP();
+
+      // Pop the last frame.
       vm->fiber->frame_count--;
 
       // If no more call frames. We're done.
@@ -754,6 +761,7 @@ PKInterpretResult vmRunScript(PKVM* vm, Script* _script) {
       Var on = POP();
       String* name = script->names.data[READ_SHORT()];
       PUSH(varGetAttrib(vm, on, name));
+      CHECK_ERROR();
       DISPATCH();
     }
 
@@ -762,6 +770,7 @@ PKInterpretResult vmRunScript(PKVM* vm, Script* _script) {
       Var on = PEEK();
       String* name = script->names.data[READ_SHORT()];
       PUSH(varGetAttrib(vm, on, name));
+      CHECK_ERROR();
       DISPATCH();
     }
 
@@ -772,6 +781,7 @@ PKInterpretResult vmRunScript(PKVM* vm, Script* _script) {
       String* name = script->names.data[READ_SHORT()];
       varSetAttrib(vm, on, name, value);
       PUSH(value);
+      CHECK_ERROR();
       DISPATCH();
     }
 
@@ -864,7 +874,7 @@ PKInterpretResult vmRunScript(PKVM* vm, Script* _script) {
     OPCODE(MOD):
     {
       Var r = POP(), l = POP();
-      PUSH(varModulo(vm, r, l));
+      PUSH(varModulo(vm, l, r));
       CHECK_ERROR();
       DISPATCH();
     }

test/examples/fib.pk

@@ -0,0 +1,17 @@
+
+## Fib test.
+
+res = ''
+
+def fib(n)
+  a = 0; b = 1
+  for _ in 0..n
+   res += to_string(a) + " "
+    temp = a;
+	a = b;
+	b += temp;
+  end
+end
+
+fib(10)
+assert(res == '0 1 1 2 3 5 8 13 21 34 ')

test/examples/prime.pk

@@ -1,3 +1,8 @@
+
+## Prime numbers.
+
+res = ''
+
 def is_prime(n)
   if n < 2 then return false end  
   for i in 2..n
@@ -6,11 +11,13 @@ def is_prime(n)
   return true
 end
 
-def print_all_primes(n)
+def get_all_primes(n)
   for i in 0..n
-    if is_prime(i) then print(i) end
+    if is_prime(i)
+		res += to_string(i) + ' '
+	end
   end
 end
 
-
+get_all_primes(20)
-print_all_primes(10)
+assert(res == '2 3 5 7 11 13 17 19 ')

test/lang/locals.pk

@@ -1,16 +0,0 @@
-
-## Local variable test.
-
-seq = ''
-def fib(n)
-  a = 0; b = 1
-  for _ in 0..n
-   seq += to_string(a) + " "
-    temp = a;
-	a = b;
-	b += temp;
-  end
-end
-
-fib(10)
-assert(seq == '0 1 1 2 3 5 8 13 21 34 ')

test/run_tests.bat

@@ -4,8 +4,8 @@ set files=(           ^
 	lang\basics.pk    ^
 	lang\import.pk    ^
 	lang\if.pk        ^
-	lang\locals.pk    ^
 	                  ^
+	examples\fib.pk   ^
 	examples\prime.pk ^
 )