While is working but untested, read more

* TODO: break and continue keywords need to be implemented
* TODO: while-then needs testing
* Fixed the parser not liking zero-length strings

scripts/fizzbuzz.toy

@@ -0,0 +1,27 @@
+
+
+//moment of truth
+var counter: int = 1;
+
+while (counter <= 100) {
+	var result: string = "";
+
+	if (counter % 3 == 0) {
+		result = result .. "fizz";
+	}
+
+	if (counter % 5 == 0) {
+		result = result .. "buzz";
+	}
+
+	//finally
+	if (result == "") {
+		print counter;
+	}
+	else {
+		print result;
+	}
+
+	counter += 1;
+}
+

scripts/looping.toy

@@ -0,0 +1,9 @@
+var a: int = 0;
+
+while(a < 10) {
+	print a;
+	a += 1;
+}
+
+print "Finished";
+

source/toy_ast.c

@@ -116,6 +116,16 @@ void Toy_private_emitAstIfThenElse(Toy_Bucket** bucketHandle, Toy_Ast** astHandl
 	(*astHandle) = tmp;
 }
 
+void Toy_private_emitAstWhileThen(Toy_Bucket** bucketHandle, Toy_Ast** astHandle, Toy_Ast* condBranch, Toy_Ast* thenBranch) {
+	Toy_Ast* tmp = (Toy_Ast*)Toy_partitionBucket(bucketHandle, sizeof(Toy_Ast));
+
+	tmp->type = TOY_AST_WHILE_THEN;
+	tmp->whileThen.condBranch = condBranch;
+	tmp->whileThen.thenBranch = thenBranch;
+
+	(*astHandle) = tmp;
+}
+
 void Toy_private_emitAstPrint(Toy_Bucket** bucketHandle, Toy_Ast** astHandle) {
 	Toy_Ast* tmp = (Toy_Ast*)Toy_partitionBucket(bucketHandle, sizeof(Toy_Ast));
 

source/toy_ast.h

@@ -19,6 +19,7 @@ typedef enum Toy_AstType {
 
 	TOY_AST_ASSERT,
 	TOY_AST_IF_THEN_ELSE,
+	TOY_AST_WHILE_THEN,
 	TOY_AST_PRINT,
 
 	TOY_AST_VAR_DECLARE,
@@ -131,6 +132,12 @@ typedef struct Toy_AstIfThenElse {
 	Toy_Ast* elseBranch;
 } Toy_AstIfThenElse;
 
+typedef struct Toy_AstWhileThen {
+	Toy_AstType type;
+	Toy_Ast* condBranch;
+	Toy_Ast* thenBranch;
+} Toy_AstWhileThen;
+
 typedef struct Toy_AstPrint {
 	Toy_AstType type;
 	Toy_Ast* child;
@@ -177,6 +184,7 @@ union Toy_Ast {                     //32 | 64 BITNESS
 	Toy_AstCompound compound;       //16 | 24
 	Toy_AstAssert assert;           //16 | 24
 	Toy_AstIfThenElse ifThenElse;   //16 | 32
+	Toy_AstWhileThen whileThen;     //16 | 24
 	Toy_AstPrint print;             //8  | 16
 	Toy_AstVarDeclare varDeclare;   //16 | 24
 	Toy_AstVarAssign varAssign;     //16 | 24
@@ -198,6 +206,7 @@ void Toy_private_emitAstCompound(Toy_Bucket** bucketHandle, Toy_Ast** astHandle,
 
 void Toy_private_emitAstAssert(Toy_Bucket** bucketHandle, Toy_Ast** astHandle, Toy_Ast* child, Toy_Ast* msg);
 void Toy_private_emitAstIfThenElse(Toy_Bucket** bucketHandle, Toy_Ast** astHandle, Toy_Ast* condBranch, Toy_Ast* thenBranch, Toy_Ast* elseBranch);
+void Toy_private_emitAstWhileThen(Toy_Bucket** bucketHandle, Toy_Ast** astHandle, Toy_Ast* condBranch, Toy_Ast* thenBranch);
 void Toy_private_emitAstPrint(Toy_Bucket** bucketHandle, Toy_Ast** astHandle);
 
 void Toy_private_emitAstVariableDeclaration(Toy_Bucket** bucketHandle, Toy_Ast** astHandle, Toy_String* name, Toy_Ast* expr);

source/toy_parser.c

@@ -352,8 +352,9 @@ static Toy_AstFlag literal(Toy_Bucket** bucketHandle, Toy_Parser* parser, Toy_As
 		case TOY_TOKEN_LITERAL_STRING: {
 			char buffer[parser->previous.length + 1];
 			unsigned int escapeCounter = 0;
-
 			unsigned int i = 0, o = 0;
+
+			if (parser->previous.length > 0) { //BUGFIX: compensate for zero-length strings
 				do {
 					buffer[i] = parser->previous.lexeme[o];
 					if (buffer[i] == '\\' && parser->previous.lexeme[++o]) {
@@ -377,6 +378,7 @@ static Toy_AstFlag literal(Toy_Bucket** bucketHandle, Toy_Parser* parser, Toy_As
 					}
 					i++;
 				} while (parser->previous.lexeme[o++] && i < parser->previous.length);
+			}
 
 			buffer[i] = '\0';
 			unsigned int len = i - escapeCounter; //NOTE: len is ONLY the string length
@@ -699,6 +701,21 @@ static void makeIfThenElseStmt(Toy_Bucket** bucketHandle, Toy_Parser* parser, To
 	Toy_private_emitAstIfThenElse(bucketHandle, rootHandle, condBranch, thenBranch, elseBranch);
 }
 
+static void makeWhileStmt(Toy_Bucket** bucketHandle, Toy_Parser* parser, Toy_Ast** rootHandle) {
+	Toy_Ast* condBranch = NULL;
+	Toy_Ast* thenBranch = NULL;
+
+	//while (condBranch)
+	consume(parser, TOY_TOKEN_OPERATOR_PAREN_LEFT, "Expected '(' after 'while' keyword");
+	makeExpr(bucketHandle, parser, &condBranch);
+	consume(parser, TOY_TOKEN_OPERATOR_PAREN_RIGHT, "Expected ')' after 'while' condition");
+
+	// { thenBranch }
+	makeDeclarationStmt(bucketHandle, parser, &thenBranch);
+
+	Toy_private_emitAstWhileThen(bucketHandle, rootHandle, condBranch, thenBranch);
+}
+
 static void makePrintStmt(Toy_Bucket** bucketHandle, Toy_Parser* parser, Toy_Ast** rootHandle) {
 	makeExpr(bucketHandle, parser, rootHandle);
 	Toy_private_emitAstPrint(bucketHandle, rootHandle);
@@ -771,10 +788,15 @@ static void makeStmt(Toy_Bucket** bucketHandle, Toy_Parser* parser, Toy_Ast** ro
 		return;
 	}
 
+	//TODO: break & continue
+
 	//while-then
+	else if (match(parser, TOY_TOKEN_KEYWORD_WHILE)) {
+		makeWhileStmt(bucketHandle, parser, rootHandle);
+		return;
+	}
+
 	//for-pre-clause-post-then
-	//break
-	//continue
 	//return
 	//import
 

source/toy_routine.c

@@ -319,7 +319,7 @@ static unsigned int writeInstructionIfThenElse(Toy_Routine** rt, Toy_AstIfThenEl
 
 	unsigned int thenEndAddr = SKIP_INT(rt, code); //parameter to be written later
 
-	//emit then branch
+	//emit then-branch
 	writeRoutineCode(rt, ast.thenBranch);
 
 	if (ast.elseBranch != NULL) {
@@ -349,6 +349,37 @@ static unsigned int writeInstructionIfThenElse(Toy_Routine** rt, Toy_AstIfThenEl
 	return 0;
 }
 
+static unsigned int writeInstructionWhileThen(Toy_Routine** rt, Toy_AstWhileThen ast) {
+	//TODO: begin
+	unsigned int beginAddr = CURRENT_ADDRESS(rt, code);
+
+	//cond-branch
+	writeRoutineCode(rt, ast.condBranch);
+
+	//emit the jump word (opcode, type, condition, padding)
+	EMIT_BYTE(rt, code, TOY_OPCODE_JUMP);
+	EMIT_BYTE(rt, code, TOY_OP_PARAM_JUMP_RELATIVE);
+	EMIT_BYTE(rt, code, TOY_OP_PARAM_JUMP_IF_FALSE);
+	EMIT_BYTE(rt, code, 0);
+
+	unsigned int endAddr = SKIP_INT(rt, code); //parameter to be written later
+
+	//emit then-branch
+	writeRoutineCode(rt, ast.thenBranch);
+
+	//jump to begin to repeat the conditional test
+	EMIT_BYTE(rt, code, TOY_OPCODE_JUMP);
+	EMIT_BYTE(rt, code, TOY_OP_PARAM_JUMP_RELATIVE);
+	EMIT_BYTE(rt, code, TOY_OP_PARAM_JUMP_ALWAYS);
+	EMIT_BYTE(rt, code, 0);
+
+	EMIT_INT(rt, code, beginAddr - (CURRENT_ADDRESS(rt, code) + 4)); //this sets a negative value
+
+	OVERWRITE_INT(rt, code, endAddr, CURRENT_ADDRESS(rt, code) - (endAddr + 4));
+
+	return 0;
+}
+
 static unsigned int writeInstructionPrint(Toy_Routine** rt, Toy_AstPrint ast) {
 	//the thing to print
 	writeRoutineCode(rt, ast.child);
@@ -603,6 +634,10 @@ static unsigned int writeRoutineCode(Toy_Routine** rt, Toy_Ast* ast) {
 			result += writeInstructionIfThenElse(rt, ast->ifThenElse);
 			break;
 
+		case TOY_AST_WHILE_THEN:
+			result += writeInstructionWhileThen(rt, ast->whileThen);
+			break;
+
 		case TOY_AST_PRINT:
 			result += writeInstructionPrint(rt, ast->print);
 			break;

tests/cases/test_ast.c

@@ -26,6 +26,7 @@ int test_sizeof_ast_64bit() {
 	TEST_SIZEOF(Toy_AstCompound, 24);
 	TEST_SIZEOF(Toy_AstAssert, 24);
 	TEST_SIZEOF(Toy_AstIfThenElse, 32);
+	TEST_SIZEOF(Toy_AstWhileThen, 24);
 	TEST_SIZEOF(Toy_AstPrint, 16);
 	TEST_SIZEOF(Toy_AstVarDeclare, 24);
 	TEST_SIZEOF(Toy_AstVarAssign, 24);
@@ -61,6 +62,7 @@ int test_sizeof_ast_32bit() {
 	TEST_SIZEOF(Toy_AstCompound, 16);
 	TEST_SIZEOF(Toy_AstAssert, 12);
 	TEST_SIZEOF(Toy_AstIfThenElse, 16);
+	TEST_SIZEOF(Toy_AstWhileThen, 12);
 	TEST_SIZEOF(Toy_AstPrint, 8);
 	TEST_SIZEOF(Toy_AstVarDeclare, 12);
 	TEST_SIZEOF(Toy_AstVarAssign, 16);