public void TestWhile()
{
var while_ = new While();
while_.Init(new Rel(new Token('>'), new Constant(42), new Constant(99)), new Stmt());
while_.Gen(10, 88);
//output:
// iffalse 42 > 99 goto L88
//L1: goto L 10
}
/// <summary>
///
/// </summary>
/// <returns></returns>
public Stmt Stmt()
{
Expr expr;
Stmt s1, s2, savedStmt;
switch (_look.TagValue)
{
case ';':
this.Move();
return(Sara.Stmt.Null);
case Tag.IF:
this.Match(Tag.IF);
this.Match('(');
expr = this.Bool();
this.Match(')');
s1 = this.Stmt();
if (_look.TagValue != Tag.ELSE)
{
return(new If(expr, s1));
}
this.Match(Tag.ELSE);
s2 = this.Stmt();
return(new IfElse(expr, s1, s2));
case Tag.WHILE:
var whileNode = new While();
savedStmt = Sara.Stmt.Enclosing;
Sara.Stmt.Enclosing = whileNode;
this.Match(Tag.WHILE);
this.Match('(');
expr = this.Bool();
this.Match(')');
s1 = this.Stmt();
whileNode.Init(expr, s1);
Sara.Stmt.Enclosing = savedStmt;
return(whileNode);
case Tag.DO:
var doNode = new Do();
savedStmt = Sara.Stmt.Enclosing;
Sara.Stmt.Enclosing = doNode;
this.Match(Tag.DO);
s1 = this.Stmt();
this.Match(Tag.WHILE);
this.Match('(');
expr = this.Bool();
this.Match(')');
this.Match(';');
doNode.Init(s1, expr);
Sara.Stmt.Enclosing = savedStmt;
return(doNode);
case Tag.BREAK:
this.Match(Tag.BREAK);
this.Match(';');
return(new Break());
case '{':
return(this.Block());
default:
return(this.Assign());
}
}
/// <summary>
///
/// </summary>
/// <returns></returns>
public Stmt Stmt()
{
Expr expr;
Stmt s1, s2, savedStmt;
switch(_look.TagValue)
{
case ';':
this.Move();
return Sara.Stmt.Null;
case Tag.IF:
this.Match(Tag.IF);
this.Match('(');
expr = this.Bool();
this.Match(')');
s1 = this.Stmt();
if (_look.TagValue != Tag.ELSE)
return new If(expr, s1);
this.Match(Tag.ELSE);
s2 = this.Stmt();
return new IfElse(expr, s1, s2);
case Tag.WHILE:
var whileNode = new While();
savedStmt = Sara.Stmt.Enclosing;
Sara.Stmt.Enclosing = whileNode;
this.Match(Tag.WHILE);
this.Match('(');
expr = this.Bool();
this.Match(')');
s1 = this.Stmt();
whileNode.Init(expr, s1);
Sara.Stmt.Enclosing = savedStmt;
return whileNode;
case Tag.DO:
var doNode = new Do();
savedStmt = Sara.Stmt.Enclosing;
Sara.Stmt.Enclosing = doNode;
this.Match(Tag.DO);
s1 = this.Stmt();
this.Match(Tag.WHILE);
this.Match('(');
expr = this.Bool();
this.Match(')');
this.Match(';');
doNode.Init(s1, expr);
Sara.Stmt.Enclosing = savedStmt;
return doNode;
case Tag.BREAK:
this.Match(Tag.BREAK);
this.Match(';');
return new Break();
case '{':
return this.Block();
default:
return this.Assign();
}
}
