2 files changed, 71 insertions, 2 deletions
diff --git a/guix/build/go-build-system.scm b/guix/build/go-build-system.scm
index 1a716cea77..282df19f24 100644
--- a/guix/build/go-build-system.scm
+++ b/guix/build/go-build-system.scm
@@ -42,7 +42,7 @@
 ;; structure called a 'workspace' [1].  This workspace can be found by Go via
 ;; the GOPATH environment variable.  Typically, all Go source code and compiled
 ;; objects are kept in a single workspace, but GOPATH may be a list of
-;; directories [2].  In this go-build-system we create a filesystem union of
+;; directories [2].  In this go-build-system we create a file system union of
 ;; the Go-language dependencies. Previously, we made GOPATH a list of store
 ;; directories, but stopped because Go programs started keeping references to
 ;; these directories in Go 1.11:
@@ -127,7 +127,7 @@
 ;; Code:
 
 (define* (setup-go-environment #:key inputs outputs #:allow-other-keys)
-  "Prepare a Go build environment for INPUTS and OUTPUTS.  Build a filesystem
+  "Prepare a Go build environment for INPUTS and OUTPUTS.  Build a file system
 union of INPUTS.  Export GOPATH, which helps the compiler find the source code
 of the package being built and its dependencies, and GOBIN, which determines
 where executables (\"commands\") are installed to.  This phase is sometimes used
diff --git a/guix/build/po.scm b/guix/build/po.scm
new file mode 100644
index 0000000000..47ff67541c
--- /dev/null
+++ b/guix/build/po.scm
@@ -0,0 +1,69 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2019 Julien Lepiller <julien@lepiller.eu>
+;;;
+;;; 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 regex)
+  #: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 (parse-tree->assoc parse-tree)
+  "Converts a po PARSE-TREE to an association list."
+  (define regex (make-regexp "\\\\n"))
+  (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 (regexp-substitute/global #f regex msgid 'pre "\n" 'post)
+               (regexp-substitute/global #f regex msgstr 'pre "\n" 'post)
+               (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)))