private void CompileWhile(Node node)
{
var conditionIndex = this.CurrentIndex();
this.CompileExpr(node.children[0]);
var branch = new Instruction.Branch {
span = node.span
};
this.Emit(branch);
var prevContinues = this.continues;
var prevBreaks = this.breaks;
this.continues = new List <Instruction.Goto>();
this.breaks = new List <Instruction.Goto>();
var trueIndex = this.CurrentIndex();
this.CompileExpr(node.children[1]);
this.Emit(new Instruction.Discard {
span = node.children[1].span.JustAfter
});
this.Emit(new Instruction.Goto {
span = node.children[1].span.JustAfter, destination = conditionIndex
});
var afterIndex = this.CurrentIndex();
branch.destinationIfTrue = trueIndex;
branch.destinationIfFalse = afterIndex;
foreach (var cont in this.continues)
{
cont.destination = conditionIndex;
}
foreach (var br in this.breaks)
{
br.destination = afterIndex;
}
this.continues = prevContinues;
this.breaks = prevBreaks;
this.Emit(new Instruction.PushLiteral {
span = node.span.JustAfter, literal = null
});
}
private void CompileIf(Node node)
{
this.CompileExpr(node.children[0]);
var branch = new Instruction.Branch {
span = node.span
};
this.Emit(branch);
var trueIndex = this.CurrentIndex();
this.CompileExpr(node.children[1]);
this.Emit(new Instruction.Discard {
span = node.children[1].span.JustAfter
});
var gotoAfter = new Instruction.Goto {
span = node.children[1].span.JustAfter
};
this.Emit(gotoAfter);
var afterIndex = this.CurrentIndex();
var falseIndex = afterIndex;
if (node.children.Count == 3)
{
this.CompileExpr(node.children[2]);
this.Emit(new Instruction.Discard {
span = node.children[2].span.JustAfter
});
afterIndex = this.CurrentIndex();
}
branch.destinationIfTrue = trueIndex;
branch.destinationIfFalse = falseIndex;
gotoAfter.destination = afterIndex;
this.Emit(new Instruction.PushLiteral {
span = node.span.JustAfter, literal = null
});
}