template: improve parsing for escaped stuff, lint pass

The lint message doesn't have a file name, because the context is never
passed.  It's good enough for now to find this manually.

Makefile

-# Copyright (c) 2015-2016 Franco Fichtner <franco@opnsense.org>
+# Copyright (c) 2015-2017 Franco Fichtner <franco@opnsense.org>
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions
@@ -93,7 +93,8 @@ ${TEMPLATE}:
 	@cp ${.CURDIR}/Volt.pm ${PERL_DIR}/${PERL_NAME}/
 	@: > ${TEMPLATE}.pot
 .for ROOTDIR in ${PLUGINSDIRS} ${COREDIR} ${LANGDIR}
-	if [ -d ${ROOTDIR}/src ]; then \
+	@if [ -d ${ROOTDIR}/src ]; then \
+		echo ">>> Scanning ${ROOTDIR}"; \
 		${XGETTEXT_PL} -D ${ROOTDIR}/src -p ${.CURDIR} -o ${TEMPLATE}.pot; \
 		find ${ROOTDIR}/src -print0 | \
 		    xargs -0 ${XGETTEXT} -j -o ${.CURDIR}/${TEMPLATE}.pot; \

Volt.pm

@@ -16,16 +16,24 @@ sub extract {
 
     my $line = 1;
 
-    # Volt Template:
-    $line = 1;
+    # Volt Template: collect single-quoted translations
     pos($_) = 0;
-    while (m/\G(.*?(?<!\{)\{\{(?!\{).*?[:]?\s*?lang\._\('(.*?)'\)\s*?[,\]]?.*?\|?.*?\}\})/sg) {
+    while (m/\G(.*?(?<!\{)\{\{(?!\{).*?[:]?\s*?lang\._\(\s*'((?:[^\\']|\\.)*?)'\)\s*?[,\]]?.*?\|?.*?\}\})/sg) {
         my ( $vars, $str ) = ( '', $2 );
+        # escaped single-qutes must be unescaped now
+        $str =~ s/\\'/'/g;
         $line += ( () = ( $1 =~ /\n/g ) );    # cryptocontext!
         $self->add_entry( $str, $line, $vars );
     }
-}
 
+    # Lint Pass: warn about double-quoted translations
+    $line = 1;
+    pos($_) = 0;
+    while (m/\G(.*?(?<!\{)\{\{(?!\{).*?[:]?\s*?lang\._\(\s*")/sg) {
+        $line += ( () = ( $1 =~ /\n/g ) );    # cryptocontext!
+        say STDERR "???: $line: Ignored double-quoted string";
+    }
+}
 
 1;