Files
basic-computer-games/95_Weekday/perl/weekday.pl
2022-01-31 15:28:40 -05:00

250 lines
7.7 KiB
Perl
Executable File

#!/usr/bin/env perl
use 5.010; # To get 'state' and 'say'
use strict; # Require explicit declaration of variables
use warnings; # Enable optional compiler warnings
use English; # Use more friendly names for Perl's magic variables
use Term::ReadLine; # Prompt and return user input
use Time::Local qw{ timelocal }; # date-time to epoch
# FIXME timelocal() is too smart for its own good in the interpretation
# of years, and caused a bunch of Y2020 problems in Perl code that used
# it. I believe that this script avoids these problems (which only occur
# if the year is less than 1000), but it is probably safer in general to
# use timelocal_modern() or timelocal_posix(). These are also exported
# by Time::Local, but only by versions 1.28 and 1.30 respectively. This
# means that they only come (by default) with Perl 5.30 and 5.34
# respectively. Now, Time::Local is a dual-life module, meaning it can
# be upgraded from the version packaged with older Perls. But I did not
# want to assume that it HAD been upgraded. Caveat coder.
use Time::Piece; # O-O epoch to date-time, plus formatting
our $VERSION = '0.000_01';
print <<'EOD';
WEEKDAY
Creative Computing Morristown, New Jersey
WEEKDAY is a computer demonstration that
gives facts about a date of interest to you.
EOD
my $now = localtime;
my $default_date = join ',', map { $now->$_() } qw{ mon mday year };
my $today = get_date(
"Enter today's date in the form month,day,year (default: $default_date): ",
"Please enter month,day,year or return for default\n",
$default_date,
);
my $birthday = get_date(
'Ender day of birth (or other day of interest): ',
"Please enter month,day,year\n",
);
say '';
printf "%d/%d/%d %s a %s\n", $birthday->mon, $birthday->mday,
$birthday->year, tense( $today, $birthday),
( $birthday->mday == 13 && $birthday->wday == 6 ) ?
$birthday->fullday . ' the thirteenth --- Beware!' :
$birthday->fullday . '.';
if ( $birthday->epoch <= $today->epoch ) {
say '*** Happy Birthday! ***'
if $birthday->mon == $today->mon &&
$birthday->mday == $today->mday;
print <<'EOD';
Years Months Days
----- ------ ----
EOD
my @delta = map { $today->$_() - $birthday->$_() } qw{ year mon mday };
if ( $delta[2] < 0 ) {
$delta[2] += 30;
$delta[1] -= 1;
}
if ( $delta[1] < 0 ) {
$delta[1] += 12;
$delta[0] -= 1;
}
my @residue = @delta;
my $delta_days = 365 * $delta[0] + 30 * $delta[1] + $delta[2];
display_ymd( 'Your age (if birthdate)', compute_ymd( $delta_days ) );
display_ymd( 'You have slept', compute_ymd( $delta_days, 0.35,
\@residue ) );
display_ymd( 'You have eaten', compute_ymd( $delta_days, 0.17,
\@residue ) );
display_ymd(
$residue[0] > 9 ? 'You have worked/played' :
$residue[0] > 3 ? 'You have played/studied' :
'You have played',
compute_ymd( $delta_days, 0.23,
\@residue ) );
display_ymd( 'You have relaxed', \@residue );
say '';
say "\t\t*** You may retire in @{[ $birthday->year + 65 ]} ***";
}
say '';
sub compute_ymd {
my ( $delta_days, $fract, $residue ) = @ARG;
my $days = defined $fract ? int ( $delta_days * $fract ) : $delta_days;
my $years = int( $days / 365 );
$days -= $years * 365;
my $months = int( $days / 30 );
$days -= $months * 30;
if ( $residue ) {
$residue->[2] -= $days;
if ( $residue->[2] < 0 ) {
$residue->[2] += 30;
$residue->[1] -= 1;
}
$residue->[1] -= $months;
if ( $residue->[1] < 0 ) {
$residue->[1] += 12;
$residue->[0] -= 1;
}
$residue->[0] -= $years;
}
return [ $years, $months, $days ];
}
sub display_ymd {
my ( $label, $ymd ) = @ARG;
printf "%-24s%4d%6d%8d\n", $label, @{ $ymd };
return;
}
sub get_date {
my ( $prompt, $warning, $default ) = @ARG;
my ( $month, $day, $year ) = split qr< [[:punct:]] >smx, get_input(
$prompt,
sub {
return 0 unless m/ \A (?: [0-9]+ [[:punct:]] ){2} ( [0-9]+ ) \z /smx;
return 1 if $1 >= 1582;
warn "Not prepared to give day of week prior to MDLXXXII.\n";
return 0;
},
$warning,
$default,
);
return localtime timelocal( 0, 0, 0, $day, $month - 1, $year );
}
sub tense {
my ( $today, $birthday ) = @ARG;
my $cmp = $birthday->epoch <=> $today->epoch
or return 'is';
return $cmp < 0 ? 'was' : 'will be';
}
# Get input from the user. The arguments are:
# * The prompt
# * A reference to validation code. This code receives the response in
# $ARG and returns true for a valid response.
# * A warning to print if the response is not valid. This must end in a
# return.
# * A default to return if the user simply presses <return>.
# The first valid response is returned. An end-of-file terminates the
# script.
sub get_input {
my ( $prompt, $validate, $warning, $default ) = @ARG;
# If no validator is passed, default to one that always returns
# true.
$validate ||= sub { 1 };
# Create the readline object. The 'state' causes the variable to be
# initialized only once, no matter how many times this subroutine is
# called. The do { ... } is a compound statement used because we
# need to tweak the created object before we store it.
state $term = do {
my $obj = Term::ReadLine->new( 'reverse' );
$obj->ornaments( 0 );
$obj;
};
while ( 1 ) { # Iterate indefinitely
# Read the input into the topic variable, localized to prevent
# Spooky Action at a Distance. We exit on undef, which signals
# end-of-file.
exit unless defined( local $ARG = $term->readline( $prompt ) );
# Return the default if it exists AND we got an empty line
return $default if defined( $default ) && $ARG eq '';
# Return the input if it is valid.
return $ARG if $validate->();
# Issue the warning, and go around the merry-go-round again.
warn $warning;
}
}
__END__
=head1 TITLE
weekday - Play the game 'Weekday' from Basic Computer Games
=head1 SYNOPSIS
weekday.pl
=head1 DETAILS
This Perl script is a port of weekday.bas, which is the 95th entry in
Basic Computer Games.
I have replaced the manual date logic with Perl built-ins to the extent
possible. Unfortunately the kind of date math involved in the "time
spent doing ..." functionality is not well-defined, so I have been
forced to retain the original logic here. Sigh.
You can use any punctuation character you please in the date
input. So something like 2/29/2020 is perfectly acceptable.
It would also have been nice to produce a localized version that
supports day/month/year or year-month-day input, but that didn't happen.
Also nice would have been language-specific output -- especially if it
could have accommodated regional differences in which day of the week or
month is unlucky.
=head1 PORTED BY
Thomas R. Wyant, III F<wyant at cpan dot org>
=head1 COPYRIGHT AND LICENSE
Copyright (C) 2022 by Thomas R. Wyant, III
This program is free software; you can redistribute it and/or modify it
under the same terms as Perl 5.10.0. For more details, see the Artistic
License 1.0 at
L<https://www.perlfoundation.org/artistic-license-10.html>, and/or the
Gnu GPL at L<http://www.gnu.org/licenses/old-licenses/gpl-1.0.txt>.
This program is distributed in the hope that it will be useful, but
without any warranty; without even the implied warranty of
merchantability or fitness for a particular purpose.
=cut
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