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bug#50136: 28.0.50; A problem with rx-let expansion
From: |
Mattias Engdegård |
Subject: |
bug#50136: 28.0.50; A problem with rx-let expansion |
Date: |
Fri, 20 Aug 2021 20:45:41 +0200 |
20 aug. 2021 kl. 19.21 skrev Michael Heerdegen <michael_heerdegen@web.de>:
> I guess it's not very useful for the current mechanism. With a
> macro-like thing, the expansion would just not use the value if it's nil. The
> expander would check whether the argument was provided.
Yes. It was (and is) a trade-off between the simpler "template-like" semantics
currently used and the programmatic "execute code" semantics of Lisp macros.
The idea was that the simpler semantics would be simpler and sufficient for
most uses, and `eval` forms could always be employed in other cases.
I'm still fretting over having made the wrong call, and that at least I should
have omitted parametrised rx definitions until better understood.
If you just have one optional argument, try &rest -- at least its default-case
semantics are crystal clear (no arguments inserted). Obviously, you could also
use separate rx macros for different parameter lists:
(rx-let ((delimited (grp delim) (seq delim (group-n grp (* (not delim)) delim)))
(double-quoted (grp) (delimited grp ?\")))
etc.
- bug#50136: 28.0.50; A problem with rx-let expansion, Michael Heerdegen, 2021/08/20
- bug#50136: 28.0.50; A problem with rx-let expansion, Michael Heerdegen, 2021/08/20
- bug#50136: 28.0.50; A problem with rx-let expansion, Mattias Engdegård, 2021/08/20
- bug#50136: 28.0.50; A problem with rx-let expansion, Michael Heerdegen, 2021/08/20
- bug#50136: 28.0.50; A problem with rx-let expansion,
Mattias Engdegård <=
- bug#50136: 28.0.50; A problem with rx-let expansion, Michael Heerdegen, 2021/08/21
- bug#50136: 28.0.50; A problem with rx-let expansion, Mattias Engdegård, 2021/08/21
- bug#50136: 28.0.50; A problem with rx-let expansion, Michael Heerdegen, 2021/08/23
- bug#50136: 28.0.50; A problem with rx-let expansion, Mattias Engdegård, 2021/08/23
- bug#50136: 28.0.50; A problem with rx-let expansion, Mattias Engdegård, 2021/08/23
- bug#50136: 28.0.50; A problem with rx-let expansion, Michael Heerdegen, 2021/08/23
- bug#50136: 28.0.50; A problem with rx-let expansion, Mattias Engdegård, 2021/08/23
- bug#50136: 28.0.50; A problem with rx-let expansion, Richard Stallman, 2021/08/20