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1 point by rocketnia 2560 days ago | link | parent

"Does that seem right?"

Yeah, I don't know why Arc's 'compose is a macro. I think I've tried to (apply compose ...) at least once and gotten bitten by that. ^^


"I still don't follow your arguments about hygiene. I suppose it's conceivable that code could use args2179 directly without going through gensym. Or that compose could call itself recursively and override $args in the caller's scope, and that it would be for some reason undesirable. Is either scenario what you were thinking of?"

I don't think so.... What I mean is, is it possible for the value inserted with ",$f" or ",$g" to contain the symbol '$args (assuming $ isn't a reader macro) in a way that causes it to be confused with the lambda's meaning of '$args?

  mac compose($f $g)
    `(lambda '$args
       eval `(,,$f (,,$g ,@$args)))

1 point by akkartik 2560 days ago | link

Ah, I see. The answer is no, there can be no $vars after evaluation. $ is indeed expanded at read time.