source: tools/po_convertor/po_to_lang.php

<?php

$OriginalLangFileName = 'lang-en.php';
$TranslatedFileName = 'boonex-dolphin-7-cs.po';
$LangFileName = 'lang-cs.php';

// Build dictionary
$Dictionary = array();
$Source = file_get_contents($OriginalLangFileName);
$Source = explode("\n", $Source);
foreach($Source as $Line)
{
  $Parts = explode('=>', $Line);
  if(count($Parts) == 2)
  {                 
    $MsgId = substr(trim($Parts[0]), 1, -1);
    $MsgStr = trim($Parts[1]);
    if(substr($MsgStr, -1) == ',') $MsgStr = substr($MsgStr, 0, -1);
    $MsgStr = substr($MsgStr, 1, -1);
    $Dictionary[$MsgId] = $MsgStr;
  }
}

// Load PO file
$PoDictionary = array();
$Source = file_get_contents($TranslatedFileName);
$Source = explode("\n", $Source);
foreach($Source as $Line)
{
  $Command = substr($Line, 0, strpos($Line, ' '));
  $Param = substr(trim(substr($Line, strpos($Line, ' '))), 1, -1);
  if($Command == 'msgid') $MsgId = $Param;
  else if($Command == 'msgstr') $PoDictionary[$MsgId] = $Param;
}

// Create Lang file
$Output = array(
  "<?",
  "",
  '$LANG_INFO = array(',
  "  'Name' => 'cs', 'Flag' => 'cz', 'Title' => 'Czech'",
  ");",
  "",
  '$LANG = array(',
);

foreach($Dictionary as $Item => $Word2)
{
  $Word = str_replace("\'", "'", $Word2);
  $Word = str_replace('"', '\"', $Word);
  if(array_key_exists($Word, $PoDictionary) and ($PoDictionary[$Word] != '')) $Line = "  '".$Item."' => '".$PoDictionary[$Word]."',";
    else $Line = "  '".$Item."' => '".$Word2."',";
  $Output[] = $Line;
}
$Output[] = ");";
$Output[] = "?>";

file_put_contents($LangFileName, implode("\r\n", $Output));

?>