Thursday, September 1, 2011

Mortal combat

A slightly confused anonymous commenter (I get to say such things about anonymous commenters, right?) reminded me of this quote by Ray Dillinger:
The scheme community is now very invested in its macrology; they got there by long hard work and emotional processing and yelling and screaming and weeping and gnashing of teeth, and they still remember the pain of not having a standard macrology. You will not pry it away except from their cold dead fingers, and you will not redefine it without defeating them in mortal combat.
I think the commenter misunderstood my earlier post. Syntactic extension is absolutely necessary, and modern Scheme macro systems are a fine way to do it.

5 comments:

  1. Have you had a chance to re-read Dybvig's "Expansion Passing Style"? I really see that as a far-too-neglected work, because it came along about the same time as the fervor over "hygiene". I'd much rather have the power over the hygiene, if I had to choose. It's trivial to implement, and then defining new expansions is just as easy.

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  2. Yes, but I drank so much hygiene kool-aid, that you will not pry it away except from my cold dead fingers, and I must say that I find Kernel's story even more convincing (the basic idea being to never quote in the first place).

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  3. Patrick, I don't know what your objections to hygienic macro systems are. Recent variants such as SRFI 72 are an advance over old-school Lisp macros on all fronts. And Kernel shows that fexprs make it even easier to be hygienic - by dropping macros-as-preprocessors, and instead making lexically-scoped fexprs the core part of the language, thereby being able to reuse plain old lexical scope itself for hygiene - as it was meant to be all along.

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  4. "Syntactic extension is absolutely necessary"

    Syntactic abstraction is necessary. I'm not at all convinced about the 'extension' aspect, though. Recently, I'm aiming at user-definable syntax without extensibility.

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