use strict;
use Data::Dumper;
...

my %results;

foreach my $name (@diffarray) {
    my $code_name = "${name}_diff";
    no strict 'refs';
    my $code = \&{ $code_name };
    $results{ $name } = [ $code->() ];
};

print Dumper \%results;

##</code><code>##

use strict;
use Data::Dumper;
...

my %results;
my %dispatch = (
    test => \&test_diff,
    info => \&info_diff,
    path => \&path_diff,
    ...
);

foreach my $name (@diffarray) {
    if ( ! exists $dispatch{$name}) {
        die "Don't know how to handle name '$name'.";
    };
    my $code = $dispatch{$name};
    $results{ $name } = [ $code->() ];
};

print Dumper \%results;