perl 正则表达式，用于将多行调用匹配到 c function

Question

I'm looking to have a regex to match all potentially multiline calls to a variadic c function. The end goal is to print the file, line number, and the fourth parameter of each call, but unfortunately I'm not there yet. So far, I have this:

 perl -ne 'print if s/^.*?(func1\s*\(([^\)\(,]+||,|\((?2)\))*\)).*?$/$1/s' test.c

with test.c:

int main() {
        func1( a, b, c, d);
        func1( a, b,
               c, d);
        func1( func2(), b, c, d, e );
        func1( func2(a), b, c, d, e );
        return 1;
}

-- which does not match the second call. The reason it doesn't match is that the s at the end of the expression allows . to match newlines, but doesn't seem to allow [..] constructs to match newlines. I'm not sure how to get past this.

I'm also not sure how to reference the fourth parameter in this... the $2 , $3 do not get populated in this (and even if they did I imagine I would get some issues due to the recursive nature of the regex).

Answer 1

Not Perl but perhaps simpler:

$ cpp -D'func1(a,b,c,d,...)=SHOW(__FILE__,__LINE__,d)' test.c |
  grep SHOW
        SHOW("test.c",2,d);
        SHOW("test.c",3,d)
        SHOW("test.c",5,d);
        SHOW("test.c",6,d);
$ cpp -D'func1(a,b,c,d,...)=SHOW(__FILE__,__LINE__,a)' test.c |
  grep SHOW 
        SHOW("test.c",2,a);
        SHOW("test.c",3,a)
        SHOW("test.c",5,func2());
        SHOW("test.c",6,func2(a))
$

Answer 2

This should catch your functions, with caveats

perl -0777 -wnE'@f = /(func1\s*\( [^;]* \))\s*;/xg; s/\s+/ /g, say for @f' tt.c

I use the fact that a statement must be terminated by ; . This excludes an accidental ; in a comment though, and it excludes calls to this being nested inside another call. If that is possible then quite a bit more need be done to parse it.

However, further parsing the captured calls, presumably by commas, is complicated by the fact that a nested call may well, and realistically, contain commas. How about this

func1( a, b, f2(a2, b2), c );

This becomes a far more interesting little parsing problem. Or, how about macros?

Can you clarify what kinds of things one doesn't have to account for?