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Re: need for macros (was Re: Icon)
From: Matthias Felleisen <firstname.lastname@example.org>
Subject: need for macros (was Re: Icon)
Date: Thu, 20 Dec 2001 20:47:13 -0500 (EST)
Note that there is no need for any syntax transformations, this is pure
Haskell. You can get surprisingly far without macros when just about
everything is a first-class value...
That's not true.
I dare say that what Lauri Alanko wrote *is* true:
(a) There is no need for any syntax transformations *for this
particular problem*, namely expressing (a simplified version of)
the Icon success/failure/generator mechanism.
(b) You can indeed "get surprisingly far without macros" when
everything, including functions, is a first class value.
There are three reasons for introducing a syntactic
abstraction (macro) rather than a function:
1. new binding forms
2. implicit quoting or, more generally, a data sub-language
3. an order of evaluation that is incompatible with evaluation
A lazy language makes macros fro 3 unnecessary. A function with first-class
functions still needs macros for 1; otherwise you keep writing
foo (fn x => ...)
all over the place.
And what Matthias has written here is also true (and important).