compile large project within emacs - emacs

Question

A large project may have directory with several level depth. Emacs's default compile command is "make -k", if I modified a certain source code, then typed "M-x compile RET RET", it will execute "make -k" under the directory which the source code lies.
I think I can write a function to determine if the Makefile exist under current directory, if yes, keep searching under the parent directory until find the top level directory, then execute the building command, it would be right like my expectation.
However, I'm not very clearly how to start, could anyone give me some hints to start? Like the function or variable I may encounter. Thanks.

Answer 1

You can try to use something like:
(setq compile-command
'(let ((mf (locate-dominating-file default-directory "Makefile")))
(if mf (setq mf (file-name-directory mf)))
(concat (if (and mf (not (equal mf default-directory)))
(format "cd %s; "
(shell-quote-argument
(file-relative-name
(directory-file-name mf)))))
"make -k ")))

Answer 2

There is a smarter-compile in marmalade.
From the documentation....When you require it, you can specify a list of cons cells, each one like (TEST . COMMAND).
COMMAND is used for the compile-command when
the TEST succeeds.
TEST can be:
a string. In this case it is used as a regex,
and matched against the filename associated to the
buffer. The TEST succeeds when the regex matches.
a symbol, representing the major-mode. In this case
if the buffer uses that major mode, the TEST
succeeds.
a symbol, representing any function with a name not
ending in \"-mode\". In this case, the function is
called and if it returns non-nil, the TEST
succeeds.
a list of forms. In this case the forms are eval'd,
and if the return value is non-nil, the TEST
succeeds.
So you could produce a function that does the scan for makefile in parent directories,
and use that as your TEST.
According to the documentation, if the COMMAND is nil, then the package uses the result of the TEST as the compile command. Which means you would need only one function, returning a make command referencing the makefile in the appropriate directory.

Answer 3

Take a look at: http://emacswiki.org/emacs/CompileCommand
"C-h v compile-command" directly from emacs.

Answer 4

Here's a solution for people who prefer bash scripting over Emacs Lisp. In my .emacs I define a command which saves all buffers and runs a bash script which compiles the project.
(defun save-all-and-compile () (interactive)
(save-some-buffers 1)
(shell-command "make-and-run.sh &"))
(add-hook 'c-mode-common-hook (lambda ()
(local-set-key (kbd "<f5>") 'save-all-and-compile)))
For small projects the script could be as simple as
#!/bin/bash
make -j && ./<main>
where 'main' is the name of your executable. For larger projects one would first need to locate the root directory. Similarly, you could have different scripts (bound for different keys) for building and running the program. And then some more scripts for testing different parts of the project. But these are just details one can figure out for themselves.
Make sure the script is run asynchronously using '&'. This way the Async Shell Command buffer will open with the output from make and your project and will stay open.
EDIT
Based on the discussion below it appears I have initially overthought it and the solution is quite simple. Instead of passing the usual 'make' or 'make -k' to compile-command one could use a shell script which first navigates to the project's root directory and the builds.
(setq compile-command "script.sh")