#:configure-flags flags #~'() or #:configure-flags flags #~()

#:configure-flags flags #~'() or #:configure-flags flags #~()

[Feng Shu]

Hello:

I grep guix.git, and find two form, I would like to know which one is
right:

#:configure-flags flags #~'()

or 

#:configure-flags flags #~()



--------------------------------------------------------------------------------
-*- mode: grep; default-directory: "~/guix/guix/" -*-
Grep started at Thu Jan 19 13:26:17

find -H . -type d \( -path \*/SCCS -o -path \*/RCS -o -path \*/CVS -o -path \*/MCVS -o -path \*/.src -o -path \*/.svn -o -path \*/.git -o -path \*/.hg -o -path \*/.bzr -o -path \*/_MTN -o -path \*/_darcs -o -path \*/\{arch\} \) -prune -o \! -type d \( -name .\#\* -o -name \*.o -o -name \*\~ -o -name \*.bin -o -name \*.lbin -o -name \*.so -o -name \*.a -o -name \*.ln -o -name \*.blg -o -name \*.bbl -o -name \*.elc -o -name \*.lof -o -name \*.glo -o -name \*.idx -o -name \*.lot -o -name \*.fmt -o -name \*.tfm -o -name \*.class -o -name \*.fas -o -name \*.lib -o -name \*.mem -o -name \*.x86f -o -name \*.sparcf -o -name \*.dfsl -o -name \*.pfsl -o -name \*.d64fsl -o -name \*.p64fsl -o -name \*.lx64fsl -o -name \*.lx32fsl -o -name \*.dx64fsl -o -name \*.dx32fsl -o -name \*.fx64fsl -o -name \*.fx32fsl -o -name \*.sx64fsl -o -name \*.sx32fsl -o -name \*.wx64fsl -o -name \*.wx32fsl -o -name \*.fasl -o -name \*.ufsl -o -name \*.fsl -o -name \*.dxl -o -name \*.lo -o -name \*.la -o -name \*.gmo
  -o -name \*.mo -o -name \*.toc -o -name \*.aux -o -name \*.cp -o -name \*.fn -o -name \*.ky -o -name \*.pg -o -name \*.tp -o -name \*.vr -o -name \*.cps -o -name \*.fns -o -name \*.kys -o -name \*.pgs -o -name \*.tps -o -name \*.vrs -o -name \*.pyc -o -name \*.pyo \) -prune -o \( -path ./\^\\.idea\$ -o -path ./\^\\.vscode\$ -o -path ./\^\\.ensime_cache\$ -o -path ./\^\\.eunit\$ -o -path ./\^\\.git\$ -o -path ./\^\\.hg\$ -o -path ./\^\\.fslckout\$ -o -path ./\^_FOSSIL_\$ -o -path ./\^\\.bzr\$ -o -path ./\^_darcs\$ -o -path ./\^\\.pijul\$ -o -path ./\^\\.tox\$ -o -path ./\^\\.svn\$ -o -path ./\^\\.stack-work\$ -o -path ./\^\\.ccls-cache\$ -o -path ./\^\\.cache\$ -o -path ./\^\\.clangd\$ -o -path ./TAGS \) -prune -o  -type f \( -name \* -o -name .\* \) -exec grep --color=auto -i -nH --null -e \#\:configure-flags\ flags\ \#\~ \{\} +
./gnu/packages/emacs.scm:424:       ((#:configure-flags flags #~'())
./gnu/packages/emacs.scm:445:       ((#:configure-flags flags #~'())
./gnu/packages/emacs.scm:464:       ((#:configure-flags flags #~'())
./gnu/packages/emacs.scm:489:       ((#:configure-flags flags #~'())
./gnu/packages/emacs.scm:508:       ((#:configure-flags flags #~'())
./gnu/packages/gstreamer.scm:1080:         ((#:configure-flags flags #~'())
./gnu/packages/maths.scm:2708:       ((#:configure-flags flags #~'())
./gnu/packages/python.scm:685:        ((#:configure-flags flags #~())
./gnu/packages/serialization.scm:200:       ((#:configure-flags flags #~'())
./gnu/packages/tor.scm:141:       ((#:configure-flags flags #~'())
./gnu/packages/wxwidgets.scm:177:       ((#:configure-flags flags #~'())
./gnu/packages/wxwidgets.scm:228:       ((#:configure-flags flags #~'())
./gnu/packages/freedesktop.scm:208:       ((#:configure-flags flags #~'())

Grep exited abnormally with code 1 at Thu Jan 19 13:26:18

Re: #:configure-flags flags #~'() or #:configure-flags flags #~()

[Tobias Geerinckx-Rice]

Hi!

It's not about 'right' (why would grepping Guix return wrong code...? Impossible! :-).  It's a matter partly of preference and partly of using the best tool for the job.

Omitted from your second example is a call to list, and the #~ that both have in common is just syntactic sugar for (gexp ...).

So the two forms you're comparing are:

  (gexp '("a" "b" "c"))
  (gexp (list "a" "b" "c"))

Both are completely equivalent when they contain only strings.  Choose whichever you like.

When you have several procedures to call, calling 'list' can look cleaner:

  (list (string-append "foo=" bar) "baz")

Although strictly speaking ` uses fewer characters and is just as correct:

  `(,(string-append "foo=" bar) "baz")

Most Guix developers prefer (list ...) because it's more self-explanatory to people unfamiliar with Lisps.  However, 'quoting is such a fundamental building block that it probably matters little in practice.

Your name looks familiar so I'll assume you understand basic Lisps concepts like quote & quasiquote.  If not, I strongly suggest learning the basics, it will make Guix much less mysterious.

As long as configure-flag gets a list, it matters little how you construct it:

  #~(append (list "my" "flags")
            '("are" "many")
           (string-append "colo" "ured"))

Just be consistent.



Kind regards,

T G-R

Sent on the go.  Excuse or enjoy my brevity.

Re: #:configure-flags flags #~'() or #:configure-flags flags #~()

[Feng Shu]

Tobias Geerinckx-Rice <me@tobias.gr> writes:

> Hi!
>
> It's not about 'right' (why would grepping Guix return wrong code...? Impossible! :-).  It's a matter partly of preference and partly of using the best tool for the job.
>
> Omitted from your second example is a call to list, and the #~ that both have in common is just syntactic sugar for (gexp ...).

:-), I just want to know, in below code: we should code #~'() or #~() after flags.

(substitute-keyword-arguments (package-arguments ...)
         ((#:configure-flags flags #~'())
                                   ^^^^^
           ...))

Re: #:configure-flags flags #~'() or #:configure-flags flags #~()

[Tobias Geerinckx-Rice]

In this example, only #~'() makes sense.  #~() is nonsensical here and will cause a syntax error when ungexped.

Kind regards,

T G-R

Sent on the go.  Excuse or enjoy my brevity.