public object Visit(LiteralExpr expr)
{
return(expr.Value);
}
Stmt ForStatement()
{
Consume(TokenType.LeftParen, "Expected opening '('.");
Stmt initializer = null;
if (MatchNext(TokenType.Var))
{
initializer = VarDeclaration();
}
else if (MatchNext(TokenType.SemiColon))
{
initializer = null;
}
else
{
initializer = ExpressionStatement();
}
Expr conditional = null;
if (!MatchNext(TokenType.SemiColon))
{
conditional = Expression();
Consume(TokenType.SemiColon, "Expecting ';' in for loop");
}
Expr incrementer = null;
if (!MatchNext(TokenType.RightParen))
{
incrementer = Expression();
Consume(TokenType.RightParen, "Expected closing ')' in for loop");
}
var body = Statement();
if (incrementer != null)
{
body = new BlockStmt(new List <Stmt> {
body,
new ExpressionStmt(incrementer)
});
}
if (conditional == null)
{
conditional = new LiteralExpr(true);
}
body = new WhileStmt(conditional, body);
if (initializer != null)
{
body = new BlockStmt(new List <Stmt> {
initializer,
body
});
}
return(body);
}