[fabriceleal]

Could you open source it? I'm very interested in seeing how one would do that, I've been thinking about writing one myself, for PHP (I've a somewhat large codebase to inherit, that only works in a old version of PHP, and I might need to migrate it).

[smu]

I don't have the IP for the code so I can't copy it here, but what I did was very simple and the gist of it is described below:

The parser used regular expressions to recognise function definitions and calls in those definitions. I used file names as the function scope, this was good enough because there were no two functions with identical names in the same file. Function calls became the following terms: "calls(x,y,z).", meaning that function x in file y calls z.

These "calls" terms actually define a directed graph. If you google "prolog path through directed graph", there are lots of hits that will help you out. The following (untested) code should get you started:

    %there is a path if there is a call
    path(Caller, File, Called, [calls(Caller, File, Called)]) :- calls(Caller, File, Called). 
    %there is a path if there is a call to some function and there is a path from that function
    path(Caller, File, Called, [calls(Caller, File, A) | P]) :- calls(Caller, File, A), path(A, _, Called).

After that, you can find all possible paths with "findall/3" and check for existence of a certain known good/bad function with "member/2" (again, google is your friend)

Due to some properties of the code, this simple approach worked well enough for me. Hopefully this helps you out.

[RBerenguel]

Probably needs a green cut in the first term... Or maybe not. I'm quite backtracking-puzzled about green cuts in generic terms I write, so thinking about them in others' code is even more puzzling :)