Adds REPEAT and WHILE loop.

trainscript/file01.ts

@@ -4,7 +4,8 @@ VAR res : INT;
 PUB main(x : INT) → c : INT
 BEGIN
 #	factorial(10) → res;
-	fibonacci(7) → res;
+#	fibonacci(7) → res;
+	problem1(1000) → res;
 END
 
 PUB factorial(number : INT) → result : INT
@@ -25,3 +26,21 @@ BEGIN
 	ELSE
 		fibonacci(n - 1) + fibonacci(n - 2) → f;
 END
+
+# If we list all the natural numbers below 10 that are
+# multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of
+# these multiples is 23.
+# Find the sum of all the multiples of 3 or 5 below 1000.
+PUB problem1(max : INT) → r : INT | iter : INT
+BEGIN
+	1 → iter;
+	0 → r;
+	WHILE iter < max DO
+	BEGIN
+		IF (iter % 5) = 0 THEN
+			r + iter → r;
+		ELSEIF (iter % 3) = 0 THEN
+			r + iter → r;
+		iter + 1 → iter;
+	END
+END

trainscript/trainscript.l

@@ -55,6 +55,7 @@ FROM            { return KW_FROM; }
 TO              { return KW_TO; }
 UNTIL           { return KW_UNTIL; }
 WHILE           { return KW_WHILE; }
+DO              { return KW_DO; }
 [0-9]+\.[0-9]*  { yylval->fval = atof(yytext); return REAL; }
 [0-9]+          { yylval->ival = atoi(yytext); return INT; }
 [a-zA-Z0-9']+   { yylval->text = strdup(yytext); return IDENTIFIER; }

trainscript/trainscript.y

@@ -106,6 +106,7 @@ void yyerror(void *scanner, const char *s);
 %token KW_TO
 %token KW_UNTIL
 %token KW_WHILE
+%token KW_DO
 
 %type <type> typeName
 %type <varDecl> variableDeclaration
@@ -128,6 +129,7 @@ void yyerror(void *scanner, const char *s);
 %type <instruction> expression
 %type <instruction> condition
 %type <instruction> elseIfLoop
+%type <instruction> loop
 
 %type <expressions> expressionList
 
@@ -284,11 +286,16 @@ instruction:
 	block { $$ = $1; }
 |	expression SEMICOLON { $$ = $1; }
 |	condition { $$ = $1; }
+|	loop { $$ = $1; }
+;
+
+loop:
+	KW_REPEAT instruction { $$ = new RepeatEndlessExpression($2); }
+|	KW_WHILE expression KW_DO instruction { $$ = new RepeatWhileExpression($2, $4); }
 ;
 
 condition:
 	KW_IF expression KW_THEN instruction elseIfLoop { $$ = new IfExpression($2, $4, $5); }
-//|	KW_IF expression KW_THEN instruction KW_ELSE instruction { $$ = new IfExpression($2, $4, $6); }
 ;
 
 elseIfLoop:

trainscript/tsvm.hpp

@@ -428,4 +428,75 @@ namespace trainscript
 			return Variable::Void;
 		}
 	};
+
+	class RepeatEndlessExpression :
+			public Instruction
+	{
+	public:
+		Instruction *block;
+
+		RepeatEndlessExpression(Instruction *block) :
+			block(block)
+		{
+
+		}
+
+		Variable execute(LocalContext &context) const override {
+			if(this->block == nullptr) {
+				if(verbose) printf("REPEAT: missing block.\n");
+				return Variable::Invalid;
+			}
+
+			while(true)
+			{
+				Variable result = this->block->execute(context);
+				(void)result;
+			}
+			return Variable::Void;
+		}
+	};
+
+
+	class RepeatWhileExpression :
+			public Instruction
+	{
+	public:
+		Instruction *condition;
+		Instruction *block;
+
+		RepeatWhileExpression(Instruction *condition, Instruction *block) :
+			condition(condition),
+			block(block)
+		{
+
+		}
+
+		Variable execute(LocalContext &context) const override {
+			if(this->condition == nullptr) {
+				if(verbose) printf("REPEAT: missing condition.\n");
+				return Variable::Invalid;
+			}
+			if(this->block == nullptr) {
+				if(verbose) printf("REPEAT: missing block.\n");
+				return Variable::Invalid;
+			}
+
+			while(true)
+			{
+				Variable cond = this->condition->execute(context);
+
+				if(cond.type != Type::Boolean) {
+					printf("REPEAT: Invalid expression type.\n");
+					return Variable::Invalid;
+				}
+
+				if(cond.boolean == false) {
+					break;
+				}
+
+				this->block->execute(context);
+			}
+			return Variable::Void;
+		}
+	};
 }