bool IBoundExprVisitor <bool> .Visit(BoundWhileExpr expr)
{
mJumpTable.PatchJumpBack("while");
// evaluate the condition
expr.Condition.Accept(this);
mJumpTable.JumpIfFalse("end");
// body
expr.Body.Accept(this);
// jump back to loop
mJumpTable.JumpBack("while");
// exit loop
mJumpTable.PatchJump("end");
return(true);
}
IBoundExpr IUnboundExprVisitor<IBoundExpr>.Visit(WhileExpr expr)
{
var bound = new BoundWhileExpr(expr.Condition.Accept(this), expr.Body.Accept(this));
if (bound.Condition.Type != Decl.Bool)
{
throw new CompileException(expr.Position, String.Format(
"Condition of while/do is returning type {0} but should be Bool.",
bound.Condition.Type));
}
if (bound.Body.Type != Decl.Unit)
{
throw new CompileException(expr.Position, String.Format(
"Body of while/do is returning type {0} but should be Unit.",
bound.Body.Type));
}
return bound;
}