Perl to generate code in other languages

I use perl to write code in other languages such as C and assembly. The core of the technique is the embedding of perl code in a perl string via

  "perl string @{[eval{ <code> }]} perl string"
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The technique is illustrated in the code below. I have also used this technique to do spread-sheet type calculations (replacement for Excel).

Languages such as Verilog and VHDL require the user to type the same information in different forms in multiple places -- a good use for perl would be to type the essential information once and have perl reproduce it in different forms and in different places as required by the Verilog/VHDL being generated. But I haven't coded in these languages in a while and so don't have an example to provide here.

A recent post indicated that others too make of perl for such ends. So here's a thread for sharing techniques used for similar ends.

#!/usr/bin/perl
use warnings;
use strict;
$| = 1;

# template to illustrate using perl to generate files 
# in other languages such as C

# in the editor, good to set filetype to c (rather than perl)

my $a_file_c = '';
my $copyright = '';

$copyright =<<here_doc;  #{{{3
/* ****

  blah blah 

********************************************************* */
here_doc
#}}}
# ---

$a_file_c =<<here_doc;  #{{{3
$copyright 

#include <stdio.h>

int main( )  /* {{{3 */
{
  int rc;
  
  printf("Hello World!\n");

here_doc
# }}}
# ---

# pure perl code

my $key_var = 'a_key_c_var';

# next block of c-code has perl executable code inside it
#    the perl code is captured in $stuff and then inserted  
#    into $a_file_c

$a_file_c .=<<here_doc;  #{{{3
    for(int foo=0; foo<1000; foo++)
    {
@{[eval{  
       my $stuff='';

       foreach(0, 2)
       {
          $stuff .= "#ifdef DO_WORK_"."$_\n";
          $stuff .= "        $key_var = $_;\n";
          $stuff .= "        $key_var = $key_var ** $_;\n";
          $stuff .= "#endif\n";
       }
       $stuff
       }]}

// more C-code

   while (int j > 0)
   { 
      must_do = some_more + thing;
   }

} // end main
here_doc
#}}}
# ---


my $foo = '';
$foo = 'a_file.c';
  open (OUT, ">$foo") or die "Unable to open $foo for writing:$!\n"; 
  binmode OUT;
  print OUT $a_file_c;
  close OUT;

__END__
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