Re: nested #if directive matching matching

The range operator is not going to help you much in this case (if you do not want to rely on indentation which I do not suggest). But you can simply count the depth of nesting the if's:

#!/usr/bin/perl

use warnings;
use strict;

my $depth;
while (<DATA>) {
    /#ifdef|#if|#ifndef/ and $depth++;
    print unless $depth;
    /#endif/ and $depth--; # this comes after the print not to be prin
+ted
}


__DATA__
{

 #if 1
  #define done 9
  #define do 10
  #ifdef
    #define def1 11
    #define thread 12
  #endif
  #define mutex 13
  #define inter 14 
 #endif
 #define intel 15
 #define intel_64 16
}
[download]

Comment on Re: nested #if directive matching matching Download Code

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Re^2: nested #if directive matching matching by roboticus (Chancellor) on Jun 26, 2012 at 12:22 UTC
choroba: Actually, you do need a stack if you're going to properly handle the #else clauses. Otherwise, you won't remember the previous value(s) of the print vs. don't print states. `#if 0 this shouldn't print #if 1 nor should this #else nor this #end #else but this should #if 1 as should this #else but not this #end This should print, but where are you storing the information to know it without a stack? #else If you got that one right, howzabout this one? #end` [download] ...roboticus When your only tool is a hammer, all problems look like your thumb.	[reply] [d/l]
Re^3: nested #if directive matching matching by choroba (Cardinal) on Jun 26, 2012 at 12:53 UTC
That was not part of the spec :-)	[reply]
Re^4: nested #if directive matching matching by Anonymous Monk on Jun 26, 2012 at 19:35 UTC
Using the counter, bitshift left and increment if true. Else is an XOR 1. Endif is a bitshift right. Initialize with a sentinel value so you know when you're done.	[reply]
Re^5: nested #if directive matching matching by GrandFather (Saint) on Jun 26, 2012 at 21:13 UTC
Re^2: nested #if directive matching matching by tobyink (Canon) on Jun 26, 2012 at 10:12 UTC
You probably don't want `#else` to increment `$depth`. `perl -E'sub Monkey::do{say$_,for@_,do{($monkey=[caller(0)]->[3])=~s{::}{ }and$monkey}}"Monkey say"->Monkey::do'`	[reply] [d/l] [select]
Re^3: nested #if directive matching matching by choroba (Cardinal) on Jun 26, 2012 at 10:16 UTC
Thanks, removed. I took it from the OP, and it is not present in the test data :-) BTW, /#if/ matches both /#ifdef/ and /#ifndef/...	[reply]