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Re: Adding wc to Bournish
From: |
Efraim Flashner |
Subject: |
Re: Adding wc to Bournish |
Date: |
Tue, 14 Jun 2016 12:27:13 +0300 |
User-agent: |
Mutt/1.6.1 (2016-04-27) |
On Wed, Jun 08, 2016 at 05:43:09PM +0200, Ludovic Courtès wrote:
> Efraim Flashner <address@hidden> skribis:
>
> > On Sun, Jun 05, 2016 at 10:37:12PM +0200, Ludovic Courtès wrote:
>
> [...]
>
> >> I’ll commit a couple of fixes for bugs I just found and that prevent us
> >> from doing:
> >>
> >> (compile "ls" #:from %bournish-language #:to 'scheme).
>
> (This should be be ‘read-and-compile’, not ‘compile’.)
>
> Done in f82c58539e1f7b9b864e68ea2ab0c6a17c15fbb5. Take a look at
> tests/bournish.scm for examples of what is expected.
>
ok
> > From ebce5076177314bfd17a53019b3f6b6888762b01 Mon Sep 17 00:00:00 2001
> > From: Efraim Flashner <address@hidden>
> > Date: Sun, 22 May 2016 14:56:06 +0300
> > Subject: [PATCH] bournish: Add `wc' command.
> >
> > * guix/build/bournish.scm (file-size, wc-c-command, wc-l-command,
> > lines+chars, wc-command, wc-command-implementation): New variables.
> > (%commands): Add wc command.
>
> [...]
>
> > +(define* (wc-command-implementation filelist #:optional args)
>
> ‘files’, not ‘filelist’.
>
ok
> > + (let ((files (filter (lambda (file)
> > + (catch 'system-error
> > + (lambda ()
> > + (lstat file))
> > + (lambda args
> > + (let ((errno (system-error-errno args)))
> > + (format (current-error-port) "~a: ~a~%"
> > + file (strerror errno))
> > + #f))))
>
> ‘stat’ rather than ‘fstat’.
>
ok
> > + (for-each
> > + (lambda (file)
> > + (let-values (((lines chars)
> > + (call-with-input-file file lines+chars)))
> > + (match args
> > + (#\l
> > + (format #t "~a ~a~%" lines file))
> > + (#\c
> > + (format #t "~a ~a~%" chars file))
> > + (_
> > + (format #t "~a ~a ~a~%" lines chars file)))))
> > + files)))
>
> OK.
>
In the end I went with 3 separate functions for the three commands
(`wc', `wc -l', `wc -c') like you mentioned later.
> > +(define (wc-command args . rest)
> > + (let* ((flags (cond ((string=? args "-l") #\l)
> > + ((string=? args "-c") #\c)
> > + (else #\nul)))) ; no flags, "args" is a file
>
> I’d rather make it:
>
> (define (wc-commands . args)
> (cond ((member "-l" args) …)
> ((member "-c" args) …)
> (else …)))
>
> Instead of the #\nul thing, I think it’d be best to have separate
> procedures for -l, -c, and the other case.
This also looks nicer, and I was able to strip the `-l' or `-c' before
passing the ,args to the implementation function.
>
> > + ((@@ (guix build bournish) wc-command-implementation)
> > + (if (char=? flags #\nul) (cons args rest) rest) flags)))
>
> This is still not emitting code. :-) IOW, there should be a quasiquote
> here.
>
> You can see that by running:
>
> (use-modules (system base compile) (guix build bournish))
> (read-and-compile (open-input-string "wc -l foo")
> #:from %bournish-language #:to 'scheme)
>
> This should return something like:
>
> `((@ (guix build bournish) wc-l-command-implementation) '("foo"))
>
got this one fixed, which in turn broke the implementation code ;) In
the end I went with not a list, so it came out like this:
scheme@(guile-user)> (read-and-compile (open-input-string "wc -l foo bar baz")
#:from %bournish-language #:to 'scheme)
$1 = ((@@ (guix build bournish) wc-l-command-implementation) "foo" "bar" "baz")
> Makes sense? We’re almost done.
>
> Please take a look at
> <https://www.gnu.org/software/guix/manual/html_node/Coding-Style.html>
> to make the last review super fast. ;-)
>
> Thank you!
>
> Ludo’.
I've attached what hopefully is the last patch for wc :) I took (and put
somewhere safe) the other code I wrote that does wc-c by calling (stat
file) and the one for wc-l that opens the file as a port and reads for
#\newlines.
--
Efraim Flashner <address@hidden> אפרים פלשנר
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- Re: Adding wc to Bournish, Efraim Flashner, 2016/06/05
- Re: Adding wc to Bournish, Ludovic Courtès, 2016/06/05
- Re: Adding wc to Bournish, Efraim Flashner, 2016/06/07
- Re: Adding wc to Bournish, Ludovic Courtès, 2016/06/08
- Re: Adding wc to Bournish,
Efraim Flashner <=
- Re: Adding wc to Bournish, Ricardo Wurmus, 2016/06/14
- Re: Adding wc to Bournish, Efraim Flashner, 2016/06/14
- Re: Adding wc to Bournish, Efraim Flashner, 2016/06/14
- Re: Adding wc to Bournish, Ricardo Wurmus, 2016/06/14
- Re: Adding wc to Bournish, Ludovic Courtès, 2016/06/15
- Re: Adding wc to Bournish, Efraim Flashner, 2016/06/15
- Re: Adding wc to Bournish, Ludovic Courtès, 2016/06/23