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Re: Adding wc to Bournish
From: |
Ludovic Courtès |
Subject: |
Re: Adding wc to Bournish |
Date: |
Wed, 15 Jun 2016 15:56:43 +0200 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/24.5 (gnu/linux) |
Efraim Flashner <address@hidden> skribis:
> From 09eef9cd841a7d212e024be0609168611923696b 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 (lines+chars, only-files, wc-commands,
> wc-command-implementation, wc-l-command-implementation,
> wc-c-command-implementation): New variables.
s/variables/procedures/ :-)
> (%commands): Add wc command.
[...]
> +(define (only-files files)
> + (filter (lambda (file)
> + (catch 'system-error
> + (lambda ()
> + (stat file))
> + (lambda args
> + (let ((errno (system-error-errno args)))
> + (format (current-error-port) "~a: ~a~%"
> + file (strerror errno))
> + #f))))
> + files))
> +
> +(define (wc-command-implementation . files)
> + (for-each
> + (lambda (file)
> + (let-values (((lines chars)
> + (call-with-input-file file lines+chars)))
> + (format #t "~a ~a ~a~%" lines chars file)))
> + ((@@ (guix build bournish) only-files) files)))
I prefer the approach Ricardo suggested, I think it’s more concise and
clearer:
https://lists.gnu.org/archive/html/guix-devel/2016-06/msg00525.html
Also, note that @@ would not be needed here; @@ serves to access private
bindings within a specific module:
https://www.gnu.org/software/guile/manual/html_node/Using-Guile-Modules.html
Last, do not miss the bit about docstrings at:
https://www.gnu.org/software/guix/manual/html_node/Formatting-Code.html
:-)
With these changes, we’re all set. Thanks!
>From a GSoC viewpoint, I think we must move to the compilation part
now. Specifically, I think the next step is to start parsing Bash
code.
For that we could use SILex + parse-lalr, but these are not the nicest
tools for the job. Better tools would be “parsing expression grammars”
(the (ice-9 peg) module in Guile 2.1) or parser combinators, though I
don’t think there’s a directly usable Guile library for that. Maybe
Eric or David can comment?
The goal is to have a parser that returns an abstract syntax tree (AST)
as an sexp:
(parse "(cd /foo; ls $HOME) && echo *.a ; echo done")
=>
'(sequence
(success-sequence
(subshell
(sequence (command "cd" "/foo")
(command "ls" (variable-ref "HOME"))))
(command "echo" (glob "*.a")))
(command "echo" "done"))
Thoughts?
Ludo’.
- 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, 2016/06/14
- 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 <=
- Re: Adding wc to Bournish, Efraim Flashner, 2016/06/15
- Re: Adding wc to Bournish, Ludovic Courtès, 2016/06/23