Drawing A Dichotomous Key

varanasi has asked for the wisdom of the Perl Monks concerning the following question:

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Re: Drawing A Dichotomous Key
by tybalt89 (Monsignor) on May 25, 2020 at 21:49 UTC

Here's something I did for https://www.rosettacode.org/wiki/Display_an_outline_as_a_nested_table#Perl It's not exactly what I think you want, but it may be close.

#!/usr/bin/perl
# http://www.rosettacode.org/wiki/Display_an_outline_as_a_nested_table

use strict;
use warnings;

my @rows;
my $row = -1;
my $width = 0;
my $color = 0;
our $bg = 'e0ffe0';

parseoutline( do { local $/; <DATA> =~ s/\t/  /gr } );

print "<table border=1 cellspacing=0>\n";
for ( @rows )
  {
  my $start = 0;
  print "  <tr>\n";
  for ( @$_ ) # columns
    {
    my ($data, $col, $span, $bg) = @$_;
    print "    <td></td>\n" x ( $col - $start ),
      "    <td colspan=$span align=center bgcolor=#$bg> $data </td>\n"
+;
    $start = $col + $span;
    }
  print "    <td></td>\n" x ( $width - $start ), "  </tr>\n";
  }
print "</table>\n";

sub parseoutline
  {
  ++$row;
  while( $_[0] =~ /^( *)(.*)\n((?:\1 .*\n)*)/gm )
    {
    my ($head, $body, $col) = ($2, $3, $width);
    $row == 1 and local $bg = qw( ffffe0 ffe0e0 )[ $color ^= 1];
    if( length $body ) { parseoutline( $body ) } else { ++$width }
    push @{ $rows[$row] }, [ $head, $col, $width - $col, $bg ];
    }
  --$row;
  }

__DATA__
insects
  large wings
    butterfly
  small or no wings
    very long rear legs
      antenna front
        mosquito
      antenna rear
        grasshopper
    shorter rear legs
      horned head
        rhino beetle
      not horned head
        small eyes
          termite solder
        large eyes
          beetle
[download]

I used the information from the "Insects" drawing.
When the output is run through links -dump filename it outputs:

   +------------------------------------------------------------------
+------+
   |                                insects                           
+      |
   |------------------------------------------------------------------
+------|
   | large wings |                    small or no wings               
+      |
   |-------------+----------------------------------------------------
+------|
   |  butterfly  |   very long rear legs    |       shorter rear legs 
+      |
   |-------------+--------------------------+-------------------------
+------|
   |             |  antenna  | antenna rear | horned  |   not horned h
+ead   |
   |             |   front   |              |  head   |               
+      |
   |-------------+-----------+--------------+---------+---------------
+------|
   |             | mosquito  | grasshopper  |  rhino  |   small   |  l
+arge  |
   |             |           |              | beetle  |   eyes    |  e
+yes   |
   |-------------+-----------+--------------+---------+-----------+---
+------|
   |             |           |              |         |  termite  | be
+etle  |
   |             |           |              |         |  solder   |   
+      |
   +------------------------------------------------------------------
+------+
[download]

Of course, it can also be viewed in a browser.

insects

large wings small or no wings

butterfly very long rear legs shorter rear legs

antenna front antenna rear horned head not horned head

mosquito grasshopper rhino beetle small eyes large eyes

termite solder beetle

Wow, that worked :)