#!/usr/local/bin/perl

$tagfile = 'tags';

$USAGE = qq{
SYNOPSIS: Generate verilog,vhdl tags for vim.
AUTHOR:   GPL(C) Mohsin Ahmed, http://www.cs.albany.edu/~mosh
USAGE:    vtags *.v *.vhd > tags .... Adds verilog and vhdl tags for vim.
OPTIONS   
	-v         Verbose
	-o file	   Output to tagfile (default is tags).
	-filetags  Include filenames in tags
EXAMPLES:
  . vtags *.v *.vhdl rams/*.v
  . find /libv -name '*.v|*.lib' | xargs vtags
  . vtags -o tagv *.v *.vhdl rams/*.v

USAGE OF TAGS WITH VIM
  :set tag=tags,../tags            "-- in ~/.vimrc file
  $ vim -t XYZ                   -- start editing module XYZ, 
    :ta XY[tab]     Show all tags matching XY*.
    :ta XYZ         Goto first location of tag XYZ.
    :tnext          Same tag, next location.
    :tselect XYZ    Goto specific (Nth) occurrence of XYZ from a menu.

    Control-]       Goto tag of identifier under cursor.
    Control-T       Come back, pop XYZ off tag stack.

NOTES:
  . Tags are: filenames and /^(module|primitive|'define) (\\w+)/
  . We do not handle (backslash quoted) \\names.
  . Oldname: veri-tags.pl
};

while( $_ = $ARGV[0],  m/^-/ ){ shift;
    if(     m/^--$/   ){ last;
    }elsif( m/^-filetags/  ){ $filetags++;
    }elsif( m/^-[h?]/ ){ die $USAGE;
    }elsif( m/^-v/    ){ $verbose++;
    }elsif( m/^-o/    ){ $tagfile = shift || die "-o needs tagfilename\n";
    }else{ die "Unknown option '$_'\n";
    }
}

die $USAGE unless @ARGV;

my $filetype; # 1->verilog, 2->vhdl.

LINE:
while(<>){
    chomp;
    unless( $fileseen{$ARGV}++ ){                      # New file?
        my $file = $ARGV;
        if( $file =~ /\.vh/i ){
            $filetype = 1;
        }elsif( $file =~ /\.v/i ){
            $filetype = 2;
        }else{
            warn "Ignoring File '$file' type unknown?\n";
            close ARGV;
            next LINE;
        }
        $file =~ s,.*/,,;   # push a File name tag.
        push( @tags, "$file\t$ARGV\t1;\"\tF\n" ) if $filetags;
        # $file =~ s,[.][^.]*$,,;   # push again file name sans ext as tag.
        # push( @tags, "$file\t$ARGV\t1;\"\tF\n" );
        warn "File: $ARGV, tag is $file\n" if $verbose;
   }

   if( $filetype == 1 ){                               # vhdl
        s/--.*//;   # comments ignored.

        # if( m/^(entity|architecture|package\s+body)\s+(\w+)/o ){
        #     warn "$1 $2 in $ARGV\n" if $verbose;
        #     push( @tags, "$2\t$ARGV\t/$_/\n" );

        if( m/^(entity|package\s+body)\s+(\w+)/o ){
            warn "$1 $2 in $ARGV\n" if $verbose;
            push( @tags, "$2\t$ARGV\t/$_/\n" );
            # tag will have prefix ENTITY_TAGNAME for ease of completion.
            # push( @tags, "ENTITY_$2\t$ARGV\t/$_/\n" );
        }elsif( m/^(architecture)\s+(\w+)\s+of\s+(\w+)\s+is/o ){
            warn "$1 $3_$2 in $ARGV\n" if $verbose;
            #  /architecture RTL of SUPP is/ will have tag /SUPP_RTL/
            push( @tags, "$3_$2\t$ARGV\t/$_/\n" );
            # #  /architecture RTL of SUPP is/ will have tag /RTL_SUPP/
            # push( @tags, "$2_$3\t$ARGV\t/$_/\n" );
        }elsif( m/^\s*(function)\s+\"(\S+?)\".*is/o ){ # eg. function "+"
            # function .. is, otherwise it is decl, regexp is a hack.
            warn "$1 $2 in $ARGV\n" if $verbose;
            push( @tags, "$2\t$ARGV\t/$_/\n" )
        }elsif( m/^\s*(function|procedure)\s+(\w+)/o ){
            warn "$1 $2 in $ARGV\n" if $verbose;
            push( @tags, "$2\t$ARGV\t/$_/\n" )
        }
        next LINE;
    }else{  # verilog $filetype == 2   
        s,//.*,,;   # comments ignored but not /* */
        if( m/^(module|primitive|`define)\s+(\w+)/o ){
            warn "$1 $2 in $ARGV\n" if $verbose;
            push( @tags, "$2\t$ARGV\t/$_/\n" )
        }
        next LINE;
    }
}
if( $tagfile ){
	open( TAGFILE, ">$tagfile") || die "Cannot write file=$tagfile\n";
	print TAGFILE sort @tags;
	close TAGFILE;
}else{
	print sort @tags;
}