Using VIM's tags interface for OCaml programs via otags and ctags

Two scripts, octags calls the correct tags program (ctags or otags) and calls fixocamltags.pl to do fixups so VIM can read the output of otags(1).

$ cat octags

#!/bin/bash

# expected calling sequnce:
# ctags -f - --format=2 --excmd=pattern --fields=nks   \
#       --sort=no --language-force=c --c-types=dgsutvf \
#       "/home/maali/ubasic.c"
echo ctags "$@" > /tmp/run
FILENAME=${BASH_ARGV[0]}

# fix-ocaml-tags.pl script
FIXTAGS=$HOME/.local/bin/fixocamltags.pl


if [[ $FILENAME =~ \.ml[i]?\$ ]] ; then
  # otags has ugly output
  #/usr/bin/otags -o - $FILENAME | $FIXTAGS

  # ocamltags clobbers TAGS in cwd
  ocamltags $FILENAME > /tmp/run 2>&1 ; $FIXTAGS TAGS
else
  /usr/bin/ctags "$@"
fi

$ cat fixocamltags.pl

#!/usr/bin/perl
use Switch;
use Cwd;

# take an emacs-style tags file
# from 'otags' and put it in
# for for taglist vim module
# Note: 'ocamltags' might provide nicer output

$sep = "\t";
$newsection = 1;

while (<>) {
  # skip blank lines or ^L mean new section
  #if ( m/^\s+$/ ) { print "#"; next; }
  $line = $_ ;

  # section begins with ^L
  if ( $line =~ m/^\x0C$/ ) { # \x0c = ^L
    $newsection = 1;
    #print STDERR "==> New section\n";
    next;
  }
 
  # first line of each section has a filename
  if ( $newsection && ($line =~ m/^([^,]+),[0-9]+$/ ) ) {
    $fname = getcwd().'/'.$1 ;
    #print STDERR "==> New file $fname\n";
    $newsection = 0;
    next;
  }

  $newsection = 0;
  # original:
  # (stmt pattern)^?(symbol)^A(linenum),(symbol idnum)
  if ( $line =~ /^(.*)(.*)(.*)\,(.*)$/ ) {
    ($pat, $sym, $lnum, $idnum) = ( $1, $2, $3, $4 );
    #print STDERR "==> New symbol $sym\n";

    # added to taglist.vim :
    #  " ocaml language
    #  let s:tlist_def_ocaml_settings = 'ocaml;m:module;t:type;d:definition'
    #
    # get type from 1st match in pattern, if type "and"
    # use the type from last entry
    $pat =~ m/\b(.+)\b\s+\b$sym\b/;
    $rawtype = $1;
   
    switch (  $rawtype ) {
      case "and" { $type = $lasttype ; }
      case "let" { $type = "d" ; }
      case "type" { $type = "t" ; }
      case "module" { $type = "m" ; }
    }
   
    # target:
    # (symbol)\t/(pattern)/\t(file)\t(type)\tline:(line)
    print $sym.$sep.$fname.$sep.'/^'.$pat.'/;"'.$sep.$type.$sep.'line:'.$lnum."\n" if $pat;

    $lasttype = $type ;
  }
}