> The lexical context you're picking up to put on #'args in the lam > macro is the context that's sitting on the parentheses in the first > argument to 'lam' in the body of 'expand-to-lam'. that context has no > "x" bound.
OK, that explains why x is not bound. Thanks! > This is the trouble with these kinds of macros: you have to be careful > to propagate the correct lexical information thru. In this case, you > can either change expand-to-lam to carry its argument's lexical > context onto that open paren there or you can change lam to use a > different spot to get its lexical information (one that's already > being carried thru, eg the context on the actual variables for > example). I want lam to be usable by other macros without the latter needing to cooperate explicitly; I want them to "just work". So I prefer the second way. But isn't that what I'm already doing by supplying #'args to datum->syntax? (datum->syntax #'args (append (syntax->datum #'args))) I don't see how else to get "the context on the actual variables". The only other choice seems to be `stx', which also doesn't work. > The model in the JFP paper should shed some light on this, I hope. (I > seem to recall you looking at that before?) I did read it and found it helpful to appreciate what the Racket macro system has to do and how. But I guess I didn't grok it enough to be able to apply it, here. The lightbulb is flickering but not really on, yet. ____________________ Racket Users list: http://lists.racket-lang.org/users
