Here's an unasked for but suggested YAML version with round trips and a unified diff in the middle, mainly because I haven't played with YAML for a long, long time.

#!/usr/bin/perl

use strict; # https://perlmonks.org/?node_id=11152489
use warnings;

my @animals = (qw( cow camel dog cat  )); # slightly changed from 1115
+0326
my @foods   = (qw( fish pasture meat  ));
my @places  = (qw( wood sea    desert ));
my $commands = {
    select => {
        completion_list => [@animals],
        commands => {
                        give => {
                                    completion_list => \@foods,
                        },
                        take_to => {
                                    completion_list => \@places,
                        },
        },
    },
    kill  => {
        completion_list => [@animals],
    }
};

use YAML qw( DumpFile LoadFile );
my $originalfile = 'original.11152489';
my $changedfile = 'changed.11152489';
DumpFile $originalfile, $commands;
$commands->{select}{commands}{give}{completion_list}[0] .= 'es';
DumpFile $changedfile, $commands;
system "diff -u $originalfile $changedfile";
use Data::Dump 'dd'; dd 'original', LoadFile $originalfile;
use Data::Dump 'dd'; dd 'changed',  LoadFile $changedfile;
[download]

Outputs:

--- original.11152489   2023-05-30 15:43:38.568028573 -0700
+++ changed.11152489    2023-05-30 15:43:38.571361943 -0700
@@ -9,7 +9,7 @@
   commands:
     give:
       completion_list:
-        - fish
+        - fishes
         - pasture
         - meat
     take_to:
(
  "original",
  {
    kill   => { completion_list => ["cow", "camel", "dog", "cat"] },
    select => {
                commands => {
                  give => { completion_list => ["fish", "pasture", "me
+at"] },
                  take_to => { completion_list => ["wood", "sea", "des
+ert"] },
                },
                completion_list => ["cow", "camel", "dog", "cat"],
              },
  },
)
(
  "changed",
  {
    kill   => { completion_list => ["cow", "camel", "dog", "cat"] },
    select => {
                commands => {
                  give => { completion_list => ["fishes", "pasture", "
+meat"] },
                  take_to => { completion_list => ["wood", "sea", "des
+ert"] },
                },
                completion_list => ["cow", "camel", "dog", "cat"],
              },
  },
)
[download]

---

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