Git is intentionally stupid about file contents to make it simple and robust. Smalltalk has some systems like you describe. They're integrated with the compile

Git is intentionally stupid about file contents to make it simple and robust. Smalltalk has some systems like you describe. They're integrated with the compiler and Smalltalk makes that easy. Otherwise I think it's mostly that such systems are lots of work to make and maintain. Treating files as plain text has huge benefits when you consider simplicity and flexibility. The real "UNIX philosophy" is "worse is better": simpler, quicker, finished solutions are more likely to flourish (except X11).