Add language file checker.

This checker will find duplicate, missing and
superfluous constants in Serendipity's language
files.

Signed-off-by: Thomas Hochstein <thh@inter.net>

lang/checklang.php

@@ -0,0 +1,79 @@
+<?php
+if (!file_exists('checklang.active')) {
+  die('For developers only. Remove this line in PHP file to use this.');
+}
+
+// parse language file names and extract existing languages
+function get_langs($lang_dir='.') {
+    if ($dh = @opendir($lang_dir)) {
+        $languages = array();
+        while(($file = readdir($dh)) !== false) {
+            if(!preg_match('/^serendipity_lang_(.+)\.inc\.php$/', $file, $matches)) {
+                continue;
+            } else {
+                $languages[] = strtolower($matches[1]);
+            }
+        }
+    }
+    return $languages;
+}
+
+// parse language file, return constants, report duplicates
+function parse_langfile($lang='en') {
+    $langfile = sprintf('serendipity_lang_%s.inc.php',$lang);
+    if ($fh = @fopen($langfile, 'r')) {
+        $constants = array();
+        printf("\n--- Parse language file: %s\n",strtoupper($lang));
+        while (($line = fgets($fh)) !== false) {
+            if(!preg_match('/@?define\(.(.+?).,/', $line, $matches)) {
+                continue;
+            } else {
+                if(in_array($matches[1], $constants)) {
+                    printf("Duplicate constant: %s\n",$matches[1]);
+                }
+                $constants[] = $matches[1];
+            }
+        }
+        return $constants;
+    }
+    return false;
+}
+
+print "============================================================\n";
+print ":            Serendipity language file checker             :\n";
+print "============================================================\n\n";
+
+// get existing languages, remove EN
+$languages = get_langs();
+unset($languages[array_search('en', $languages)]);
+sort($languages);
+
+$constants = array();
+
+// parse EN language file
+$constants['en'] = parse_langfile();
+
+// parse all other language files and compare them to EN
+foreach ($languages as $language) {
+    $constants[$language] = array();
+    $constants[$language] = parse_langfile($language);
+    // constants in EN missing in this language
+    $missing = array_diff($constants['en'], $constants[$language]);
+    // constants in this language not known in EN
+    $added   = array_diff($constants[$language], $constants['en']);
+    // report
+    if(!empty($missing) {
+        printf("%s misses these constants:\n",strtoupper($language));
+        foreach ($missing as $display) {
+            printf("   - %s\n", $display);
+        }
+    }
+    if(!empty($added)) {
+        printf("%s has these additional constants:\n",strtoupper($language));
+        foreach ($added as $display) {
+            printf("   - %s\n", $display);
+        }
+    }
+}
+
+?>