Tree datastructures: Difference between revisions

=={{header|Perl 6}}==

{{works with|Rakudo|2019.07.1}}

Code golf is a entertaining passtime, even if it isn't appropriate for this site. To a large extent, I agree with [[User:Hout|Hout]], I am not really on board with mocking anybody, especially espousing it as an official RosettaCode position. So, feel free to mark this incorrect.

<lang perl6>#`(

Sort of vague as to what we are trying to accomplish here. If we are just

trying to transform from one format to another, probably easiest to just

perform string manipulations.

)

my $level = ' ';

my $tree = q:to/END/;

RosettaCode

encourages

code

diversity

comparison

discourages

golfing

trolling

emphasising execution speed

code-golf.io

encourages

golfing

discourages

comparison

END

sub nested-to-indent { $^str.subst: /^^ ($($level))*/, -> $/ { "{+$0} " }, :g }

sub indent-to-nested { $^str.subst: /^^ (\d+) \s* /, -> $/ { "{$level x +$0}" }, :g }

say $tree;

say my $indent = $tree.&nested-to-indent;

say my $nest = $indent.&indent-to-nested;

use Test;

is($tree, $nest, 'Round-trip equals original');

#`(

If, on the other hand, we want perform more complex transformations, better to

load it into a native data structure, which will then allow us to manipulate it

however we like.

)

my @forest = $tree.comb( /^^\S.+? <?before $ | ^^\S>/);

my $forest;

{

my $last = -1;

for @forest -> $tree {

for $tree.lines -> $line {

$line ~~ /^^ ($($level))* /;

given (my $this = +$0) cmp $last {

when More { $forest ~= "\['{$line.trim}', "; $last = $this }

when Same { $forest ~= "'{$line.trim}', " }

when Less { $forest ~= "{']' x $last - $this}, '{$line.trim}', "; $last = $this }

}

}

}

$forest ~= "{']' x 1 + $last}";

use MONKEY-SEE-NO-EVAL;

$forest.=EVAL;

}

say "\nNative data structure:\n", $forest.perl;

{

use JSON::Fast;

say "\nJSON:\n", $forest.&to-json;

}

{

use YAML;

say "\nYAML:\n", $forest.&dump;

}

</lang>

{{out}}

<pre>RosettaCode

encourages

code

diversity

comparison

discourages

golfing

trolling

emphasising execution speed

code-golf.io

encourages

golfing

discourages

comparison

0 RosettaCode

1 encourages

2 code

3 diversity

3 comparison

1 discourages

2 golfing

2 trolling

2 emphasising execution speed

0 code-golf.io

1 encourages

2 golfing

1 discourages

2 comparison

RosettaCode

encourages

code

diversity

comparison

discourages

golfing

trolling

emphasising execution speed

code-golf.io

encourages

golfing

discourages

comparison

ok 1 - Round-trip equals original

Native data structure:

$["RosettaCode", ["encourages", ["code", ["diversity", "comparison"]], "discourages", ["golfing", "trolling", "emphasising execution speed"]], "code-golf.io", ["encourages", ["golfing"], "discourages", ["comparison"]]]

JSON:

[

"RosettaCode",

[

"encourages",

[

"code",

[

"diversity",

"comparison"

]

],

"discourages",

[

"golfing",

"trolling",

"emphasising execution speed"

]

],

"code-golf.io",

[

"encourages",

[

"golfing"

],

"discourages",

[

"comparison"

]

]

]

YAML:

---

- RosettaCode

- - encourages

- - code

- - diversity

- comparison

- discourages

- - golfing

- trolling

- emphasising execution speed

- code-golf.io

- - encourages

- - golfing

- discourages

- - comparison

...</pre>