regex 2 match C function

jai has asked for the wisdom of the Perl Monks concerning the following question:

hi, can anyone give me the regex to match C-style functions. given a C source file, the regex should match all the C functions and add a header b4 the function. the functions may be of the form

int 
function(int a, char *b) {
 ... 
 return 0;
}
[download]

the regex should match:

int
function(int a, char *b)
[download]

and print:

------------------------------------------------------
/* Function : function()
      Input:
        int a :
        char *b:
      
      Output:
        int :
 
     Author :
     Date :
*/

int
function(int a, char *b)
-----------------------------------------------------------
[download]

thanks -jai

Comment on regex 2 match C function Select or Download Code

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Re: regex 2 match C function by liz (Monsignor) on Aug 13, 2003 at 08:30 UTC
I don't think a single regular expression would be the way to go, as that would imply having to read entire source-files into memory. Given the "cleanness" of the C-code, I would do this with a while loop, iterating one line at a time, and build some logic on top of that. But maybe you would like to have a look at Doxygen instead... Liz	[reply]
Re: regex 2 match C function by Skeeve (Parson) on Aug 13, 2003 at 08:31 UTC
Did you already try something? Then please show us the efforts you made. Or do you want us to do your homework? ;-)	[reply]
Re: regex 2 match C function by CombatSquirrel (Hermit) on Aug 13, 2003 at 11:27 UTC
Try this: #!perl -w use strict; undef $/; my ($header, $type, $arguments); my $file = <DATA>; $file =~ s/((\w+)\s+(\w+)\s$([^)])$\s\{)/"\/ Function: $3()\n" . " Input:\n" . do { $header = + $1; $type = $2; $arguments = $4 . ','; ''} . (join "\n", map { sprintf " + %-5s %8s : ", split } $arguments =~ m\|\s(\w+\\s+\\w+) +\s,\|g) . "\n\n" . " Output:\n" . (sprintf " %-5s : \n", $ty +pe) . "\n Author :\n Date :\n\ +/" . "\n\n$header"/ge; print $file; __DATA__ int function(int a, char b) { ... return 0; } [download] I am just a little afraid that it will also catch if-blocks and such. Hope this helped.	[reply] [d/l]
Re: Re: regex 2 match C function by jai (Sexton) on Aug 14, 2003 at 06:33 UTC
hi, thanx for the code. actually i came up with the following. foreach (@ARGV) { # Read file open(FF,"<$_") \|\| die ("Cant open $_ : $!\n"); my $t=<FF>; close FF; $t=~s/((\*\s\w+\s)+\s)($(\s\\s\w+,?)$?\s{)/${\&do( +$1,$3)}/g; # Write file open (FF, ">$_.j") \|\| die ("Cant open $_.j : $!\n"); print FF $t; close FF; } sub do($$) { my ($a,$b)=@_; my ($t1, $t2, @t3); $t1=$a,$t2=$b; $a=~s/\n/ /gm; $b=~s/\n//g; $b=~s/\s+/ /gm; $b=~s/[(\{)]/ /g; @t3=split /,/,$b; #@t3=map {"\n $_\t : " } @t3; @t3=map{sprintf "\n %-13s : ", $_} @t3; my $t=<<E; /* * Function : $a * * Inputs : \n @t3 * Author : * Date : */ $t1$t2 E } [download] I know urs is far better. as u said, it will match try, catch blocks and also constructs of type `#define add(x,y) {\` [download] I'd like the monks to give suggestions on optimizations,..	[reply] [d/l] [select]
Re: regex 2 match C function by tbone1 (Monsignor) on Aug 13, 2003 at 13:24 UTC
I know this is doable, so do it until you get it. (HINT: Think curly braces.) A friend wrote something like this when we worked together at Ameritech. However, that was years ago, and I've lost touch with him. I am not about to give away his code without permission. (I'm kinda funny that way.) -- tbone1 Ain't enough 'O's in 'stoopid' to describe that guy. - Dave "the King" Wilson	[reply]
Re: regex 2 match C function (parser) by kelan (Deacon) on Aug 13, 2003 at 13:50 UTC
You're either going to want to slurp the entire file so you can catch when the return type is on a different line, or just write a small parser, or both. I've written small parsers before using the `/\G.../gc` method explained in perlop and it isn't too difficult. Be careful that you distinguish function definitions and function calls or you could run into trouble. kelan Perl6 Grammar Student	[reply]
Re: regex 2 match C function by CombatSquirrel (Hermit) on Aug 13, 2003 at 15:47 UTC
If you don't want the whole file to be slurped in at once Read more... (2 kB) (only if it is not HW) Hope this helped (and I hope your question was not HW, but for work, documentation or something similar as I suppose it to be).	[reply] [d/l] [select]
Re^2: regex 2 match C function by Anonymous Monk on Jan 24, 2014 at 09:49 UTC
Hi, the above code will treat static as part of the return type. It would be nice if I get an algorithm for extracting return type with any number of words. For example " static inline unsigned int".	[reply]


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