A TextMate bundle for the Python-based GYP build tool (née “Generate Your Project”). Based on a TextMate language grammar originally by vidmaker; it also packages this GYP-file pretty-print tool as a bundle command.
Download the ZIP archive, decompress, rename the folder from e.g. GYP.tmbumdle-master to GYP.tmbundle – the Finder will warn you about editing a file suffix, pay it no mind – and double-click on what should have just changed from a plain folder to a TextMate bundle icon. TextMate will open, if it hasn’t already, and ask you if you’d like to install the GYP bundle (which presumably you do).