Something like this ?

#!/usr/bin/perl

# https://perlmonks.org/?node_id=1224600

use strict;
use warnings;
use Data::Dump 'dd';

my $data = <<'END';
interface XYZ
  given param1 -> child of "interface XYZ"
  given param2 -> child of "interface XYZ"
    given param2.1 -> child of "given param2"
      given param2.1.1 -> child of "given param2.1"
      given param2.1.2 -> child of "given param2.1"
    given param2.2 -> child of "given param2"
  given param3 -> child of "interface XYZ"
  given param4 -> child of "interface XYZ"
interface SECOND
  given param5 -> child of "interface SECOND"
END

my $struct = buildstruct($data);
dd $struct;

sub buildstruct
  {
  my $block = shift;
  my @answers;
  while( $block =~ /^( *)(.*)\n((?:\1 +.*\n)*)/gm )
    {
    my ($head, $rest) = ($2, $3);
    $head =~ s/ ->.*//;
    push @answers, $rest ? { $head => buildstruct($rest) } : $head;
    }
  \@answers;
  }
[download]

Outputs:

[
  {
    "interface XYZ" => [
      "given param1",
      {
        "given param2" => [
          { "given param2.1" => ["given param2.1.1", "given param2.1.2
+"] },
          "given param2.2",
        ],
      },
      "given param3",
      "given param4",
    ],
  },
  { "interface SECOND" => ["given param5"] },
]
[download]

Or do I completely misunderstand what you're asking for ?

---

---

Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!

Titles consisting of a single word are discouraged, and in most cases are disallowed outright.

Read Where should I post X? if you're not absolutely sure you're posting in the right place.

Please read these before you post! —

• How do I compose an effective node title?
• How do I post a question effectively?
• Markup in the Monastery

Posts may use any of the Perl Monks Approved HTML tags:

a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr

You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)

	For:		Use:
	&		&
	<		&lt;
	>		&gt;
	[		&#91;
	]		&#93;

Link using PerlMonks shortcuts! What shortcuts can I use for linking?

See Writeup Formatting Tips and other pages linked from there for more info.