use strict;
use warnings;

use Data::Dump qw(dd);  # for debug

# function declarations (just for syntactic sweetening).
sub remove_leading_trailing_whitespace;
sub normalize_embedded_whitespace;
sub normalize_case;

# build phrase translation dictionary.
my %dict =
  map @$_,         # expand to key/value pairs
  map { $_->[0] =  # do all key normalizations
            normalize_case
            normalize_embedded_whitespace
            remove_leading_trailing_whitespace
            $_->[0]
            ;
        $_;
        }
  # keys will be normalized in hash; value strings used as defined.
  [ 'Animal Source Food'   => q{aliment d'origine animale},         ],
  [ ' balanced      diet ' => q{regime alimentaire equilibre},      ],
  [ '   food   '           => q{aliment},                           ],
  [ 'nutrition'            => q{diet},                              ],
  [ 'nutrition assessment' => q{evaluation de l'etat nutritionnel}, ],
  ;
# dd \%dict;  # FOR DEBUG

# regex construction assumes dictionary keys are fully normalized.
my ($rx_phrase) =
    map  qr{ (?i) \b (?: $_) \b }xms,
    join ' | ',
    map  match_any_embedded_whitespace($_),
    sort { length($b) <=> length($a) }
    keys %dict
    ;
# print "$rx_phrase \n";  # FOR DEBUG

my $text = <<"EOT";
this is a nutrition assessment for animal
source     food needed
for a Balanced \t\t Diet of
FOOD for proper nutrition.
EOT
print "before: [[$text]] \n\n";

$text =~ s{ ($rx_phrase) }
          {<<$dict{ normalize_embedded_whitespace normalize_case $1 }>
+>}xmsg;
print "after: [[$text]] \n\n";

exit;

# subroutines ######################################################

# s/// and tr/// expressions assume pre-5.14 perl version: no /r
# modifier.

sub remove_leading_trailing_whitespace {
    (my $r = $_[0]) =~ s{ \A \s+ | \s+ \z }{}xmsg;  # pre-5.14
    return $r;
    }

sub normalize_embedded_whitespace {
    (my $r = $_[0]) =~ tr/ \t\n\r\f/ /s;  # pre-5.14
    return $r;
    }

sub match_any_embedded_whitespace {
    (my $r = $_[0]) =~ s{ \s+ }' \s+ 'xmsg;  # pre-5.14
    return $r;
    }

sub normalize_case { return lc $_[0]; }
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