#!/usr/bin/env -S perl -w
##!/usr/bin/env -S perl -wd

use v5.30.0;
use strict;
#use re 'debug';
#ues Regexp::Debugger;
use Test::More tests => 16;

my @strings = (
    "today's date 10.13.2023",
    "The frequency is 10346.87Hz",
);

#
# This is such an improvement over Friedl pg 194-195...
#
my $lookAhead = qr/ (?! (?: .*\.){2,}) /x;
my $regex = qr/ ^ $lookAhead [+-]? [\d.]+ $/x;
 
#
# See: https://stackoverflow.com/questions/22652393/regex-1-variable-reset
#   From: Brian Foy
#
# Never, never, never use $& without first testing for TRUE...
# See PP pg 781, the use of the word 'successful' :-(
# Also see my REinsights.pl for lengthy discussion from Brian Foy re
# when and whether $n, $`, $& and $' will be reset after unsuccessful
# matches.
#
for my $str (@strings) {
    say "\$str => $str";
    if ($str =~ / [+-]?[\d.]+ /x) {  # Pattern fails without this step; why???
        if ($& =~ $regex) {
	        say "matched";
	        say "\$& => $&" if $&;
	    } else {
	        say "unmatched";
	    }
    } else {
        say "unmatched";
    }
}

sub isFloat {
    my $case = $_[0];
#   say $case->[0], " ", $case->[1];
    if ($case->[0] =~ / [+-]?[\d.]+ /x) {       # MUST test here to use $&
        my $try = $&;
        if ($case->[1] eq 'valid') {
            like $try, $regex,
                "trying ${\(sprintf(\"%-27s: \$& => %-13s\", \"\'$case->[0]\'\", $try))} \'$case->[1]\'";
        } else {
            unlike $try, $regex,
                "trying ${\(sprintf(\"%-27s: \$& => %-13s\", \"\'$case->[0]\'\", $try))} \'$case->[1]\'";
        }
    } else {
        say "$case->[0] unmatched";
    }
}
 
my @floats = (
    [ '0.',                         'valid' ],
    [ '0.007',                      'valid' ],
    [ '.757',                       'valid' ],
    [ '125.89',                     'valid' ],
    [ '+10789.24',                  'valid' ],
    [ '+107894',                    'valid' ],
    [ '-0.0008',                    'valid' ],
    [ 'The temperature is 28.79C',  'valid' ],
    [ 'Frequency: 10877.45Hz',      'valid' ],
    [ '255.0.0.0',                'invalid' ],
    [ '255.aa',                     'valid' ],
    [ "10.13.2023, today's date", 'invalid' ],
    [ '0.119.255.255' ,           'invalid' ],
    [ 'Date: 10.13.2023 BC',      'invalid' ],
    [ '-42',                        'valid' ],
    [ '2004.04.12 Friedl nomatch','invalid, Friedl pg 195' ],
);

say "\nRunning tests...";
say "  with: $regex\n";

say "Testing mixed (valid and invalid) naked and embedded float strings...";
for my $case (@floats) {
    isFloat($case);
};

exit(0);
__END__