emacs programmatically change window size

Question

I would like to implement automatic collapse of compilation buffer to small size (but not close at a delete windows), such that upon successful compilation to window is shrunk to minimum size.

get-buffer-create returns a buffer. how can I shrink-window on window associated with that buffer? also, is there a way to store previous window size?

It is my first foray into emacs lisp programming, thank you for your help.

Answer 1

I believe there are two ways to solve this problem.

The first is to use the hook `'compilation-finish-functions', which is:

[A list of f]unctions to call when a compilation process finishes. Each function is called with two arguments: the compilation buffer, and a string describing how the process finished.

Which leads to a solution like this:

(add-hook 'compilation-finish-functions 'my-compilation-finish-function)
(defun my-compilation-finish-function (buffer resstring)
  "Shrink the window if the process finished successfully."
  (let ((compilation-window-height (if (string-match-p "finished" resstring) 5 nil)))
    (compilation-set-window-height (get-buffer-window buffer 0))))

The only problem I have with that solution is that it assumes that success can be determined by finding the string "finished" in the result string.

The other alternative is to advise 'compilation-handle-exit - which gets passed the exit-status explicitly. I wrote this advice which shrinks the window when the exit status is non-zero.

(defadvice compilation-handle-exit (around my-compilation-handle-exit-shrink-height activate)
  (let ((compilation-window-height (if (zerop (car (ad-get-args 1))) 5 nil)))
    (compilation-set-window-height (get-buffer-window (current-buffer) 0))
    ad-do-it))

Note: if the *compilation* window is still visible when you do your second compile, it will not be resized larger upon failure. If you want it to be resized, you'll need to specify a height instead of nil. Perhaps this would be to your liking (changing the first example):

(if (string-match-p "finished" resstring) 5 (/ (frame-height) 2))

The nil was replaced with (/ (frame-height) 2)