private GStmt.Stmt forStatement()
{
consume(tt.LEFT_PAREN, "Expect '(' after 'for'.");
GStmt.Stmt initializer;
if (Match(tt.SEMICOLON))
{
initializer = null;
}
else if (Match(tt.VAR))
{
initializer = varDeclaration();
}
else
{
initializer = expressionStatement();
}
GExpr.Expr condition = null;
if (!check(tt.SEMICOLON))
{
condition = expression();
}
consume(tt.SEMICOLON, "Expect ';' after loop condition.");
GExpr.Expr increment = null;
if (!check(tt.RIGHT_PAREN))
{
increment = expression();
}
consume(tt.RIGHT_PAREN, "Expect ')' after for clauses");
GStmt.Stmt body = statement();
if (increment != null)
{
body = new GStmt.Block(new List <GStmt.Stmt>()
{
body, new GStmt.Expression(increment)
});
}
if (condition == null)
{
condition = new GExpr.Literal(true);
}
body = new GStmt.While(condition, body);
if (initializer != null)
{
body = new GStmt.Block(new List <GStmt.Stmt>()
{
initializer, body
});
}
return(body);
}
public object visit_Literal_Expr(GExpr.Literal expr)
{
return(expr.value);
}