[pve-devel] [PATCH proxmox-i18n v2] js generator: extract comments from source

[Maximiliano Sandoval]

Adds a way to extract comments to the resulting .po files loosely
matching xgettext's behavior. Useful for instances like

```js
   // Translators: This is the verb, not the noun
   gettext("Profile");

   // Translators: This would read 'foo bar'
   Ext.String.format(gettext('foo {0}'), 'bar');
```

where the string is not enough to guarantee is a satisfactory
translation.

Do note that two identical messages with different comments will count
as the same message (same msgid) from the point of view of gettext. To
truly differentiate them one would need to support Context via the
pgettext function, see [1].

Unlike xgettext we require comments to start with either `TRANSLATORS`
or `i18n` (the parsing is case-insensitive) simply to avoid filling po
files with potentially confusing comments unrelated to translations.

Caveats:
  - Cannot extract multi-line comments
  - Does not understand comments in the /* foo */ form

[1] https://www.gnu.org/software/gettext/manual/html_node/Contexts.html

Signed-off-by: Maximiliano Sandoval <m.sandoval at proxmox.com>
---
 jsgettext.pl | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/jsgettext.pl b/jsgettext.pl
index 7f758fd..1c6c050 100755
--- a/jsgettext.pl
+++ b/jsgettext.pl
@@ -93,7 +93,7 @@ my $href = {
 };
 
 sub extract_msg {
-    my ($filename, $linenr, $line) = @_;
+    my ($filename, $linenr, $line, $comment) = @_;
 
     my $count = 0;
 
@@ -110,8 +110,13 @@ sub extract_msg {
 
 	if (my $po = $href->{$text}) {
 	    $po->reference($po->reference() . " $ref");
+	    if ($po->automatic && $comment) {
+		$po->automatic($po->automatic . "\n" . $comment);
+	    } elsif ($comment) {
+		$po->automatic($comment);
+	    }
 	} else {
-	    $href->{$text} = Locale::PO->new(-msgid=> $text, -reference=> $ref, -msgstr=> '');
+	    $href->{$text} = Locale::PO->new(-msgid=> $text, -reference=> $ref, -msgstr=> '', -automatic=> $comment);
 	}
     }
     die "can't extract gettext message in '$filename' line $linenr\n" if !$count;
@@ -122,10 +127,13 @@ my $sources = find_js_sources($dirs);
 
 foreach my $s (@$sources) {
     open(my $SRC_FH, '<', $s) || die "unable to open file '$s' - $!\n";
+    my $prev_line;
     while(defined(my $line = <$SRC_FH>)) {
 	if ($line =~ m/gettext\s*\(/ && $line !~ m/^\s*function gettext/) {
-	    extract_msg($s, $., $line);
+	    my ($comment) = $prev_line =~ /\/\/\s+((?:translators|i18n).*)/i;
+	    extract_msg($s, $., $line, $comment);
 	}
+	$prev_line = $line;
     }
     close($SRC_FH);
 }
-- 
2.39.2