in reply to Re: TreeDumper Parser / Inverse?
in thread TreeDumper Parser / Inverse?

Hi thanos,

To clarify, the structures I am trying to parse are generated by TreeDumper with $Data::TreeDumper::Displayaddress = 0.

Here is a quick and dirty function I have whipped up which suffices for my possible inputs, but is not quite correct for all possible inputs. Specifically, it will interpret arrays as hashes with keys 0 .. n.

#!/usr/bin/env perl use strict; use warnings FATAL => 'all'; use feature qw(say); use Test::Deep qw(eq_deeply); sub parse_treedump { my $lines = shift; my @lines = @$lines; my %obj; my @stack; my $parse_next_line = sub { my $line = shift @lines; my $key_indicator = $line =~ /\|-/ ? '|-' : '`-'; my $key_idx = index( $line, $key_indicator ); my $level = @stack; my $key_level = $key_idx / 3; if ($key_level < $level) { pop @stack until $key_level == ($level = @stack); } my $current_obj = \%obj; $current_obj = $current_obj->{$_} foreach @stack; if ($line =~ /(\w+)\s=\s(.*)$/ && $key_level == $level) { $current_obj->{$1} = $2 eq 'undef' ? undef : $2; } elsif ($line =~ /(\w+)\s\(no\selements\)/) { $current_obj->{$1} = [ ]; } elsif ($line =~ /(\w+)\s=$/) { $current_obj->{$1} = ''; } elsif ($line =~ /(\w+)/ && $key_level == $level) { push @stack, $1; $current_obj->{$1} = { }; } }; $parse_next_line->() while @lines; return \%obj } my $expected_hash = { one => 'two', three => { four => 'five', six => 'seven', eight => { nine => 'ten' }, eleven => [ ], twelve => undef, }, thirteen => 'fourteen' }; my $lines = []; while (<DATA>) { chomp; push @$lines, $_; } close DATA; my $output_hash = parse_treedump($lines); if (eq_deeply($output_hash, $expected_hash)) { say "OK"; } 1; __DATA__ |- one = two |- three | |- four = five | |- six = seven | |- eight | | `- nine = ten | |- eleven (no elements) | `- twelve = undef `- thirteen = fourteen

As you can see, the TreeDump output in the __DATA__ section gets converted to the expected hash. I would prefer it to work for all possible inputs...

Best,
Jim

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Re^3: TreeDumper Parser / Inverse?
by Arunbear (Prior) on Aug 09, 2017 at 13:04 UTC
    Here's a crazy idea. Apply some simple transforms to the the TreeDump output:
    '|- ' => '', '| ' => '', '`-' => '', '=' => ':', 'undef' => 'null',
    You may need some more, but after that the text will be in YAML format, so you can use one of the YAML parsers to convert it to a hash.
Re^3: TreeDumper Parser / Inverse?
by Anonymous Monk on Aug 09, 2017 at 13:52 UTC
    my $parse_next_line = sub { my $line = shift @lines; ... }; $parse_next_line->() while @lines;
    This is very silly. Just write
    foreach my $line (@lines) { ... }
      Good point. I started off trying to build an iterator, but eventually settled into this pseudo foreach loop as you have pointed out. Thanks for the input!
Re^3: TreeDumper Parser / Inverse?
by Anonymous Monk on Aug 09, 2017 at 15:14 UTC
    I kind of like this solution, but YMMV. The approach isn't much different from yours.
    my @stack = ({}); while (<DATA>) { s/\s+$//; # remove trailing space and newline my $depth = 0; $depth++ while $depth < @stack && s/^[|` ][- ] //; die 'malformed input' if $depth < 1; splice @stack, $depth; my $obj = $stack[-1]; if (/^(.*?) = ?(.*)/) { $obj->{$1} = $2 eq 'undef' ? undef : $2; } elsif (s/ \(no elements\)$//) { $obj->{$_} = []; } else { push @stack, $obj->{$_} = {}; } } my $output_hash = $stack[0];