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bug#28254: 26.0.50; SRFI-2 and-let*
From: |
Michael Heerdegen |
Subject: |
bug#28254: 26.0.50; SRFI-2 and-let* |
Date: |
Tue, 12 Sep 2017 20:44:11 +0200 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/26.0.50 (gnu/linux) |
Mark Oteiza <mvoteiza@udel.edu> writes:
> > Not really related to your change, but: Maybe we should additionally
> > say that THEN can refer to the bindings made in the VARLIST, but
> > ELSE to none, not even to those that resulted in non-nil values
> > before "failing".
>
> That's not true though--you can refer to the bindings in either branch:
Hmm, that feels strange. FWIW, all the scheme implementations I looked
at implemented it in a way that binding variables stops after the first
nil. OTOH I would expect that all bindings are only available from the
THIS branch (this is my personal opinion). In our case, we have
something third: always all bindings are visible in the ELSEs, e.g.
(let ((z 1))
(if-let* ((nil) (z 100))
(doesnt-matter)
z))
==> nil
That doesn't feel right.
I have two more questions:
In `internal--listify':
(defsubst internal--listify (elt)
"Wrap ELT in a list if it is not one.
If ELT is of the form ((EXPR)), listify (EXPR) with a dummy symbol."
(cond
((symbolp elt) (list elt elt))
((and (null (cdr elt))
(let ((form (car elt)))
(or (listp form) (atom form))))
(list (make-symbol "s") (car elt)))
(t elt)))
isn't (or (listp form) (atom form)) always true?
Secondly, in `internal--build-binding-value-form':
(defsubst internal--build-binding-value-form (binding prev-var)
"Build the conditional value form for BINDING using PREV-VAR."
(let ((var (car binding)))
(if (and (null (cdr binding)) (atom (car binding)) (not (symbolp (car
binding))))
`(,var (and ,prev-var ,var))
`(,var (and ,prev-var ,(cadr binding))))))
how can it happen that (car binding) is an atom but not symbolp? And if
(car binding) == var is not a symbol, how does the returned binding make
sense?
Thanks,
Michael.
- bug#28254: 26.0.50; SRFI-2 and-let*, (continued)
- bug#28254: 26.0.50; SRFI-2 and-let*, Mark Oteiza, 2017/09/04
- bug#28254: 26.0.50; SRFI-2 and-let*, Michael Heerdegen, 2017/09/05
- bug#28254: 26.0.50; SRFI-2 and-let*, Michael Heerdegen, 2017/09/06
- bug#28254: 26.0.50; SRFI-2 and-let*, Mark Oteiza, 2017/09/06
- bug#28254: 26.0.50; SRFI-2 and-let*, Michael Heerdegen, 2017/09/06
- bug#28254: 26.0.50; SRFI-2 and-let*, Mark Oteiza, 2017/09/03
- bug#28254: 26.0.50; SRFI-2 and-let*, Mark Oteiza, 2017/09/04
- bug#28254: 26.0.50; SRFI-2 and-let*, Mark Oteiza, 2017/09/08
- bug#28254: 26.0.50; SRFI-2 and-let*, Michael Heerdegen, 2017/09/12
- bug#28254: 26.0.50; SRFI-2 and-let*, Mark Oteiza, 2017/09/12
- bug#28254: 26.0.50; SRFI-2 and-let*,
Michael Heerdegen <=
- bug#28254: 26.0.50; SRFI-2 and-let*, Mark Oteiza, 2017/09/12
- bug#28254: 26.0.50; SRFI-2 and-let*, Michael Heerdegen, 2017/09/13
- bug#28254: 26.0.50; SRFI-2 and-let*, Mark Oteiza, 2017/09/13
- bug#28254: 26.0.50; SRFI-2 and-let*, Michael Heerdegen, 2017/09/13
- bug#28254: 26.0.50; SRFI-2 and-let*, Mark Oteiza, 2017/09/13
- bug#28254: 26.0.50; SRFI-2 and-let*, Michael Heerdegen, 2017/09/13
- bug#28254: 26.0.50; SRFI-2 and-let*, Mark Oteiza, 2017/09/13
- bug#28254: 26.0.50; SRFI-2 and-let*, Michael Heerdegen, 2017/09/13
- bug#28254: 26.0.50; SRFI-2 and-let*, Michael Heerdegen, 2017/09/12
- bug#28254: 26.0.50; SRFI-2 and-let*, Mark Oteiza, 2017/09/12