cross-posted from: https://lemmy.ml/post/6856563

When writing a (GNU) Makefile, there are times when you need a particular target(s) to be run before anything else. That can be for example to check the environment, ensure variables are set or prepare a particular directory layout.

… take advantage of GNU Make’s mechanism of includeing and makeing makefiles which is described in details in the manual:

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    1 year ago

    To solve your DRY problem, you may not realize that you can generate target rules from built-in functions eval and foreach and a user-defined new-line macro. Think of it like a preprocessor step.

    For example:

    # This defines a new-line macro.  It must have two blank lines.
    define nl
    
    
    endef
    
    # Generate two rules for ansible playbooks:
    $(eval $(foreach v,1 2,\
    .PHONY : ansible.run-playbook$v $(nl)\
    \
    ansible.run-playbook$v : ensure-variables cleanup-residue | $$(ansible.venv)$(nl)\
    ansible.run-playbook$v :;\
    	... $(nl)\
    ))
    

    I winged it a bit for you, but hopefully I got it right, or at least right enough you get what I’m doing with this technique.