Re^2: Data::Rmap to modify an arrayref of arrayrefs

Thanks kcott. I've gone ahead and abstracted htis into a function. Now, I'm going to try to solve it at the level of 'items' instead of at the parent level.

use strict;
use warnings;

use Data::Rmap qw(:all);
use Data::Dumper;

my $initial_lol = [ note => [ shopping => [ item => 'sample' ] ] ];

#  In $initial_lol, the new child of shopping is shopping_items
my $new_lol = newchild($initial_lol, shopping => shopping_items());

warn Dumper($new_lol);



sub newchild {
  my ($lol, $parent_arrayref_label, $new_child)=@_;

  my ($mapresult) = rmap_array {
 

  if ($_->[0] eq $parent_arrayref_label) {
    $_->[1] = $new_child;
    cut($_);
  } else {
    $_;
  }

  } $lol;

  $mapresult;

}

sub shopping_items {
  my @shopping_items;
  for my $item qw(bread butter beans) {
    push @shopping_items, [ item => $item ];
  }
  \@shopping_items;
}
[download]

The mantra of every experienced web application developer is the same: thou shalt separate business logic from display. Ironically, almost all template engines allow violation of this separation principle, which is the very impetus for HTML template engine development.

-- Terence Parr, "Enforcing Strict Model View Separation in Template Engines"

Comment on Re^2: Data::Rmap to modify an arrayref of arrayrefs Download Code

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Re^3: Data::Rmap to modify an arrayref of arrayrefs by metaperl (Curate) on Jul 03, 2011 at 00:31 UTC
tada! now I work at the item level instead of it's parent: use strict; use warnings; use Data::Rmap qw(:all); use Data::Dumper; my $initial_lol = [ note => [ shopping => [ item => 'sample' ] ] ]; # In $initial_lol, the new child of shopping is shopping_items my $new_lol = newnode($initial_lol, item => shopping_items()); warn Dumper($new_lol); sub newnode { my ($lol, $node_label, $new_node)=@_; my ($mapresult) = rmap_array { if ($_->[0] eq $node_label) { $_ = shopping_items(); cut($_); } else { $_; } } $lol; $mapresult; } sub shopping_items { my @shopping_items; for my $item qw(bread butter beans) { push @shopping_items, [ item => $item ]; } \@shopping_items; } [download] The mantra of every experienced web application developer is the same: thou shalt separate business logic from display. Ironically, almost all template engines allow violation of this separation principle, which is the very impetus for HTML template engine development. -- Terence Parr, "Enforcing Strict Model View Separation in Template Engines"	[reply] [d/l]
Close but no cigar by metaperl (Curate) on Jul 08, 2011 at 20:49 UTC
My attempt to rewrite the array at the level of the item I wanted to introduced a subtle flaw. I made it clear what data structure I wanted: `[ 'note', [ 'shopping', [ 'item', 'bread' ], [ 'item', 'butter' ], [ 'item', 'beans' ] ] ];` [download] but then the code above introduces an extra level of array referencing that is not acceptable: `[ 'note', [ 'shopping', [ [ 'item', 'bread' ], [ 'item', 'butter' ], [ 'item', 'beans' ] ] ] ];` [download] it looks like I will have to write the child list at the level of the parent instead of rewriting at the level of the child. The mantra of every experienced web application developer is the same: thou shalt separate business logic from display. Ironically, almost all template engines allow violation of this separation principle, which is the very impetus for HTML template engine development. -- Terence Parr, "Enforcing Strict Model View Separation in Template Engines"	[reply] [d/l] [select]