Shell Programming and Scripting

#!/usr/bin/nawk -f
#Autor : Paweł Łepko 
# Simple Preprocesor

BEGIN {      
   print "//preprocessing ... ";
   print "  ";
   for(i=1;i<ARGC;i++)
   {
     filename = ARGV[i]
     preproc(filename);
   }
}
END{
}

## MY FUNCTION 
function preproc(filename)
{ 
  # file preprocessing :
  while ( getline < filename )
  {
   name=""
   include_true="F"
   if ( NF >= 3 && $1=="#define" )
   {
     for(i=3;i<=NF;i++)
       name = name "" $i; # we need this for macro
     for ( def in define )
      gsub(def,define[def], name ) ; # in name we search for names defined before by define drictive 
     define[$2] = name ;
     name=""
   }
   else if ( NF==2 && $1=="#include" )
   {
     for ( def in define )
     {  
       if ( $2==def) # # check if $2 was defined by #define dericticve 
       { 
         plik = define[def];
         preproc(plik); # <--Recursive call - we have to preproc and include files defined by #include 
         inc_true="T";
       }
    }
    if ( inc_true != "T" )
    {   
        preproc($2); # the same as abowe
        print " "
    }
     else 
       inc_true="F"
  }
  else
  {
     # preprocessing ... not finished yet 
  }
  }
  return ;
}