private Stmt ForStatement()
{
Consume(TokenType.LeftParen, "Expect '(' after 'for'");
// initializer
Stmt initializer = null;
if (Match(TokenType.Semicolon))
{
initializer = null;
}
else if (Match(TokenType.Var))
{
initializer = VarDeclaration();
}
else
{
initializer = ExpressionStatement();
}
// condition
Expr condition = null;
if (!Check(TokenType.Semicolon))
{
condition = Expression();
}
Consume(TokenType.Semicolon, "Expect ';' after loop condition.");
// increment
Expr increment = null;
if (!Check(TokenType.RightParen))
{
increment = Expression();
}
Consume(TokenType.RightParen, "Expect ')' after for clauses.");
// body
Stmt body = Statement();
// desugar
if (increment != null)
{
List <Stmt> statements = new List <Stmt>();
statements.Add(body);
statements.Add(new Stmt.Expression(increment));
body = new Stmt.Block(statements);
}
if (condition == null)
{
condition = new Expr.Literal(true);
}
body = new Stmt.While(condition, body);
if (initializer != null)
{
List <Stmt> statements = new List <Stmt>();
statements.Add(initializer);
statements.Add(body);
body = new Stmt.Block(statements);
}
return(body);
}
public void Visit(Stmt.While stmt)
{
Resolve(stmt.condition);
Resolve(stmt.body);
}
