guix-play/guix/build/po.scm
Ludovic Courtès 5837b3e41f
po: Micro-optimize 'read-po-file'.
* guix/build/po.scm (parse-tree->assoc): Use dot instead of ellipsis in
'match' clause to avoid repeated calls to 'list?'.
2020-06-23 00:03:08 +02:00

80 lines
3.1 KiB
Scheme

;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2019 Julien Lepiller <julien@lepiller.eu>
;;; Copyright © 2020 Ludovic Courtès <ludo@gnu.org>
;;;
;;; This file is part of GNU Guix.
;;;
;;; GNU Guix is free software; you can redistribute it and/or modify it
;;; under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 3 of the License, or (at
;;; your option) any later version.
;;;
;;; GNU Guix is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;;; GNU General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>.
(define-module (guix build po)
#:use-module (ice-9 match)
#:use-module (ice-9 peg)
#:use-module (ice-9 textual-ports)
#:export (read-po-file))
;; A small parser for po files
(define-peg-pattern po-file body (* (or comment entry whitespace)))
(define-peg-pattern whitespace body (or " " "\t" "\n"))
(define-peg-pattern comment-chr body (range #\space #\頋))
(define-peg-pattern comment none (and "#" (* comment-chr) "\n"))
(define-peg-pattern entry all
(and (ignore (* whitespace)) (ignore "msgid ") msgid
(ignore (* whitespace)) (ignore "msgstr ") msgstr))
(define-peg-pattern escape body (or "\\\\" "\\\"" "\\n"))
(define-peg-pattern str-chr body (or " " "!" (and (ignore "\\") "\"")
"\\n" (and (ignore "\\") "\\")
(range #\# #\頋)))
(define-peg-pattern msgid all content)
(define-peg-pattern msgstr all content)
(define-peg-pattern content body
(and (ignore "\"") (* str-chr) (ignore "\"")
(? (and (ignore (* whitespace)) content))))
(define (interpret-newline-escape str)
"Replace '\\n' sequences in STR with a newline character."
(let loop ((str str)
(result '()))
(match (string-contains str "\\n")
(#f (string-concatenate-reverse (cons str result)))
(index
(let ((prefix (string-take str index)))
(loop (string-drop str (+ 2 index))
(append (list "\n" prefix) result)))))))
(define (parse-tree->assoc parse-tree)
"Converts a po PARSE-TREE to an association list."
(match parse-tree
(() '())
((entry . parse-tree)
(match entry
((? string? entry)
(parse-tree->assoc parse-tree))
;; empty msgid
(('entry ('msgid ('msgstr msgstr)))
(parse-tree->assoc parse-tree))
;; empty msgstr
(('entry ('msgid msgid) 'msgstr)
(parse-tree->assoc parse-tree))
(('entry ('msgid msgid) ('msgstr msgstr))
(acons (interpret-newline-escape msgid)
(interpret-newline-escape msgstr)
(parse-tree->assoc parse-tree)))))))
(define (read-po-file port)
"Read a .po file from PORT and return an alist of msgid and msgstr."
(let ((tree (peg:tree (match-pattern
po-file
(get-string-all port)))))
(parse-tree->assoc tree)))