// This returns a block with an initializer statement and a while statement, a
// dedicated Stmt.For class is not needed.
Stmt ParseForStatement()
{
consume(TokenType.LEFT_PAREN, "Expect '(' before for statement condition.");
Stmt initializer = null;
if (match(TokenType.VAR))
{
initializer = ParseVarDeclaration();
}
else if (!match(TokenType.SEMICOLON))
{
initializer = ParseExpressionStatement();
}
Expr condition = null;
if (!match(TokenType.SEMICOLON))
{
condition = ParseExpression();
consume(TokenType.SEMICOLON, "Expect ';' after for statement condition.");
}
Expr increment = null;
if (!match(TokenType.RIGHT_PAREN))
{
increment = ParseExpression();
consume(TokenType.RIGHT_PAREN, "Expect ')' after for statement condition.");
}
Stmt body = ParseStatement();
if (increment != null)
{
body = new Stmt.Block(new List <Stmt> {
body, new Stmt.Expression(increment)
});
}
if (condition == null)
{
condition = new Expr.Literal(true);
}
body = new Stmt.While(condition, body);
if (initializer != null)
{
body = new Stmt.Block(new List <Stmt> {
initializer, body
});
}
return(body);
}
public string visitLiteralExpr(Expr.Literal expr)
{
return(expr.value == null ? "nil" : expr.value.ToString());
}
public object visitLiteralExpr(Expr.Literal expr)
{
return(null);
}
public object visitLiteralExpr(Expr.Literal expr)
{
return(expr.value);
}
