public AstStatement VisitIf(Scope context, AstStatement.IfStmt ifStmt)
{
ifStmt.Condition = ifStmt.Condition.Accept(context, this);
ifStmt.TrueBranch = ifStmt.TrueBranch.Accept(context, this);
ifStmt.FalseBranch = ifStmt.FalseBranch?.Accept(context, this);
return(ifStmt);
}
public void VisitIf(IndentWriter context, AstStatement.IfStmt ifStmt)
{
context.WriteLine("if(");
context.Indent();
this.PrintExpression(context, ifStmt.Condition, ifStmt.Scope);
context.Unindent();
context.WriteLine(") {");
context.Indent();
ifStmt.TrueBranch.Accept(context, this);
context.Unindent();
if (ifStmt.FalseBranch != null)
{
context.WriteLine("} else {");
context.Indent();
ifStmt.FalseBranch.Accept(context, this);
context.Unindent();
}
context.WriteLine("}");
}
public List <Instruction> VisitIf(object context, AstStatement.IfStmt ifStmt)
{
// var list = new List<Instruction>();
// list.AddRange(ifStmt.Condition.Accept(this));
// list.Add(IfElseBegin));
// list.AddRange(ifStmt.TrueBranch.Accept(this));
// list.Add(IfElseElse));
// if (ifStmt.FalseBranch != null)
// {
// list.AddRange(ifStmt.FalseBranch.Accept(this));
// }
// list.Add(IfElseEnd));
// return list;
/*
* if (condition()) { statement(); }
* 1) condition();
* jmpif 2 3
* 2) statement();
* jmp 3
* 3) ...
*/
/*
* if (condition()) { statement1(); } else { statement2(); }
* 1) condition();
* jmpif 2 3
* 2) statement1();
* jmp 4
* 3) statement2();
* jmp 4
* 4) ...
*
*/
var scope = ifStmt.Scope;
if (ifStmt.FalseBranch == null)
{
/*
* if (condition()) { statement(); }
*
* condition();
* not[]
* jumpif #label
* statement();
* #label
*/
var label = this.GetNextLabel(ifStmt);
var list = new List <Instruction>();
list.AddRange(ifStmt.Condition.Accept(scope, this));
list.Add(Not);
list.Add(JumpIf, new int[] { label });
list.AddRange(ifStmt.TrueBranch.Accept(context, this));
list.Add(Label, new int[] { label });
return(list);
}
else
{
/*
* if (condition()) { statement1(); } else { statement2(); }
*
* condition();
* jumpif #labelTrue
* statement2();
* jump #labelEnd
* #labelTrue
* statement1();
* #labelEnd
*/
var labelTrue = this.GetNextLabel(ifStmt);
var labelEnd = this.GetNextLabel(ifStmt);
var list = new List <Instruction>();
list.AddRange(ifStmt.Condition.Accept(scope, this));
list.Add(JumpIf, new int[] { labelTrue });
list.AddRange(ifStmt.FalseBranch.Accept(context, this));
list.Add(Jump, new int[] { labelEnd });
list.Add(Label, new int[] { labelTrue });
list.AddRange(ifStmt.TrueBranch.Accept(context, this));
list.Add(Label, new int[] { labelEnd });
return(list);
}
}
public Tree VisitIf(object c, AstStatement.IfStmt ifStmt)
=> new Tree("if", Expr(ifStmt.Condition), ifStmt.TrueBranch.Accept(c, this), ifStmt.FalseBranch?.Accept(c, this));