Emacs check syntax of file before saving

Question

How I can prevent Emacs from saving my buffer when it contains syntax errors ?

It would by especially useful for editing source code.

I'm writing some source code into the buffer, hit C-x C-s and Emacs should position the cursor on the line containing the error. I'm correcting the error, hit the save command again, and Emacs should save the file.

Answer 1

My approach to this problem would be to rebind C-x C-s to astropanic-save-buffer which would be an elisp function that would run the contents of the current buffer through whatever your compiler/build process is. If it passed, it would run save-buffer and if there was an error it would create a new buffer/window split with the error message so you could fix it.

Consider also using the write-file-functions(more info) hook to attach workflow to save-buffer, but I'm wary of this on the grounds that while I might think that I'd want this in some modes, I wouldn't in all modes.

Answer 2

Emacs flymake mode may be close to what you want. It does dynamic compiling/syntax checking of source code for the current buffer.