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Re: Some macros to make package definitions prettier


From: Taylan Ulrich Bayırlı/Kammer
Subject: Re: Some macros to make package definitions prettier
Date: Tue, 03 Mar 2015 17:49:07 +0100
User-agent: Gnus/5.13 (Gnus v5.13) Emacs/24.4 (gnu/linux)

address@hidden (Ludovic Courtès) writes:

> I’ve applied it locally and will push shortly.

It might be too late, but I have a nitpick on my macro: the implicit
quoting of phase names 1. makes it impossible to provide them
dynamically (e.g. procedure argument), 2. might give an illusion that
they're sort of compile-time constants (like the 'delete', 'add-before',
etc. tokens are).

I guess it's fine since they are literal symbols in pretty much all
cases (or really all cases) so far, but it bothered me so I wanted to
share; it might be best to avoid such implicit-quoting in the future.


Another nitpick would be that standards-compliant syntax-rules won't
match the 'delete', 'replace', etc. literal tokens if they have a
different binding during use than during definition of the macro.  (The
identifier is matched by symbol name (i.e. "unhygienically") only if
it's unbound during both definition and use.)  But I think this is
really a problem in the Scheme standard, because this kind of macro is
probably ubiquitous in Scheme code "in the wild."  (And psyntax usually
does it the way we expect.)


Regarding the automatic conversion, I'll look into your recommendation,
and also ponder on a hand-baked solution in Guile or Elisp, but I wonder
if it will be possible to cover all edge-cases, especially comments.  On
the upside, we can auto-verify the results (sans comments and code
formatting) by comparing package objects for equality before and after
the transformation, since a use of 'modify-phases' should have the exact
same result as the direct alist mangling...

Taylan



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