Puzzle #2: cal(1)

Here's my entry. I started doing this in the Bourne shell, but halfway through I felt just too dirty writing it. So, I whipped this up in Perl, instead. Enjoy (and if you think this is too verbose, be happy that I didn't "use strict;".... at least I didn't write it in lisp).

#!/usr/bin/perl -w

$real_cal = "/usr/bin/cal";

if (@ARGV != 1 || $ARGV[0] ne "now") {
        exec($real_cal, @ARGV) || die "could not exec $real_cal: $!\n";
}

# Set $months to be our current year * 12 + the current month of the year.
# Remember, $t[5] contains the number of years since 1900.  Also, $t[4] is
# the month of the year starting at zero (Jan == 0, Dec == 11).
@t = localtime(time());
$months = (($t[5] + 1900) * 12) + $t[4];

# @cal will store the merged output of three months' output from cal(1).
@cal = ();

# Iterate over the three months for which we want data.
for $month ($months - 1, $months, $months + 1) {
        # append_cal wants the first argument to be an array reference,
        # the second argument to be the month, *numbering from one, not zero*,
        # and the last to be the year.
        append_cal(\@cal, ($month % 12) + 1, int($month / 12));
}

# Print out our data, appending newlines.
foreach $line (@cal) {
        $line =~ s/\s+$//;
        print $line, "\n";
}

#
# append_cal - Append the calendar for the specified month and year to
#              an array of lines.
# Parameters:
#       $cal:   an array reference into which to store the output from cal(1).
#       $month: month of the year, suitable for passing directly to cal(1).
#               Note that this starts at one (Jan == 1, Dec == 12).
#       $year:  year, numbering from zero (2004 == 2004).
#
sub append_cal {
        my ($cal) = shift(@_);
        my ($month) = shift(@_);
        my ($year) = shift(@_);

        my ($fh);
        my ($index);
        my ($line);

        open($fh, "$real_cal $month $year|") ||
                die "opening pipe from cal: $!\n";

        $index = 0;
        while (defined($line = <$fh>)) {
                chomp($line);

                if (!defined($$cal[$index])) {
                        $$cal[$index] = "";
                }

                $$cal[$index] .= sprintf("%-20s    ", $line);
        
                $index++;
        }

        close($fh);
}

Posted by DJ Gregor on September 29, 2004 at 09:41 PM PDT #

#!/bin/zsh -f

PATH=/usr/bin

if [[ $# -eq 1 ]]; then
        case $1 in
        (<0-12>)
                cal $1 $(date +%Y)
                ;;
        ("now")
                this=( $(date +%m) $(date +%Y) )
                next=( $(( this[1] % 12 + 1)) $this[2] )
                prev=( $(( (this[1] - 2) % 12 + 1)) $this[2] )

                (( next[1] == 1 )) && (( ++next[2] ))
                (( prev[1] == 0 )) && (( --prev[2], prev[1] = 12 ))

                sdiff =(cal $=prev) =(sdiff -w 60 =(cal $=this) =(cal $=next)) | \
                        cut -c 1-22,67-88,98-
                echo
                join -t$'\t' -o 1.2,2.2 =(join -t$'\t' -o 1.2,2.2 \
                        =(cal $=prev | cat -n) =(cal $=this | cat -n) | expand -t 23 | cat -n) \
                        =(cal $=next | cat -n) | expand -t 46
                ;;
        (*)
                exec cal $0
                ;;
        esac
else
        exec cal $@
fi

Posted by Danek Duvall on September 29, 2004 at 11:14 PM PDT #

#!/bin/sh

if [ $# -eq 1 ]; then
    case $1 in
    [0-9]|[0-9][0-9])
        cal $1 `date '+%Y'` ;;
    now)
        year=$(date '+%Y')
        mon=$(date '+%m')

        pmon=$(( ( $mon - 2 ) % 12 + 1 ))
        [ $pmon -eq 0 ] && pmon=12
        pyear=$year
        [ $pmon -gt $mon ] && pyear=$(( $pyear - 1 ))

        nmon=$(( $mon % 12 + 1 ))
        nyear=$year
        [ $nmon -lt $mon ] && nyear=$(( $nyear + 1 ))

        { cal "$pmon" "$pyear" | sed -e 's/^/a:/' ; \
          cal "$mon" "$year"   | sed -e 's/^/b:/' ; \
          cal "$nmon" "$nyear" | sed -e 's/^/c:/' ; } | \
        awk 'BEGIN { ja = jb = jc = 0;}
        /^a:/ {av[ja] = substr($0,3); ja++;}
        /^b:/ {bv[jb] = substr($0,3); jb++;}
        /^c:/ {cv[jc] = substr($0,3); jc++;}
        END {
          jmax = ja;
          if (jb > jmax) {jmax = jb;}
          if (jc > jmax) {jmax = jc;}
          for (ja = 0; ja < jmax; ja++) {
            printf "%-22s%-22s%-22s\n", av[ja],bv[ja],cv[ja];
          }
        }'
        ;;
    *)
        cal "$1" ;;
    esac
else
    cal "$@"
fi

Posted by Giorgos Keramidas on September 30, 2004 at 02:52 AM PDT #

#!/bin/perl
#
# You are not supposed to understand this, just be in awe of my perl-foo.
#
use strict;
use warnings;
my ($m, $y, @my) = (localtime())[4, 5]; $m += 1; $y += 1900;
if (@ARGV == 1 && $ARGV[0] eq 'now') {
	$my[1] = [ $m, $y ];
} elsif (@ARGV == 1 && $ARGV[0] =~ /^\d+$/ && $ARGV[0] >= 1 && $ARGV[0] <= 12) {
	$my[1] = [ $ARGV[0], $y ];
} else {
	exec('/usr/bin/cal', @ARGV) || die("Can't exec cal: $!\n");
}
$_ = $my[1][0] - 1;
@{$my[0]} = $_ == 0 ? ( 12, $my[1][1] - 1 ) : ( $_, $my[1][1] );
$_ = $my[1][0] + 1;
@{$my[2]} = $_ == 13 ? ( 1, $my[1][1] + 1 ) : ( $_, $my[1][1] );
my @cal = map([ map({ chomp($_); $_ } qx{/usr/bin/cal $_->[0] $_->[1]}) ], @my);
for ($_ = 0; $_ < 7; $_++) {
	printf("%-20s   %-20s   %-20s\n", map(shift(@{$_}) || '', @cal));
}
exit(0);

Posted by Alan Burlison on October 01, 2004 at 06:53 AM PDT #

Posted by Alan Burlison on October 01, 2004 at 07:33 AM PDT #

Posted by Alan Burlison on October 01, 2004 at 05:01 PM PDT #

Posted by Ant�nio Santos on October 07, 2004 at 07:46 AM PDT #

#!/bin/ksh -p
z=/usr/bin/cal
c(){ $z $*|sed 's/$/ /'|expand -t 23
}
date "+%Y %m"|read y m
d=0${1%%now}
[[ $d -lt 13 && $d -gt 0 ]]&&exec $z $d ${2:-$y}
[[ $1 != "now" ]]&&exec $z $*
set -A a $y $y $y
set -A b -- $((m-1)) $m $((m+1))
f[1]='a[0]=$((y-1));b[0]=12'
f[12]='a[2]=$((y+1));b[2]=1'
eval ${f[$m]}
eval paste `for i in 0 1 2; do echo '<(c '${b[$i]} ${a[$i]}')'
done`

Posted by Dave Powell on October 08, 2004 at 07:54 PM PDT #

#!/bin/ksh -p
z=/usr/bin/cal
c(){ sed 's/$/ /'|expand -t23
}
date +%Y\ %m|read y m
d=0${1%%now}
[[ $d -lt 13 && $d -gt 0 ]]&&exec $z $d ${2:-$y}
[[ $1 = now ]]||exec $z $*
set -A a $y $y $y
set -A b -- $((m-1)) $m $((m+1))
f[1]='a[0]=$((y-1));b[0]=12'
f[12]='a[2]=$((y+1));b[2]=1'
eval ${f[$m]}
eval paste `for i in 0 1 2; do echo "<($z ${b[$i]} ${a[$i]}|c)"
done`

Posted by Dave Powell on October 09, 2004 at 02:37 AM PDT #

Posted by Jaime Cardoso on October 15, 2004 at 07:21 AM PDT #

#!/bin/ksh -p
c() {
		cal $(($1%12+1)) $(($1/12)) | sed -e 's/$/	/' | expand -21
}
[[ $# -ne 1 ]] && exec cal "$@"
integer y=$(date +%Y)
[[ $1 != now ]] && {
	[[ $1 -lt 13 ]] && exec cal $1 $y || exec cal $1
}
integer m=$(date +%m)
integer d=$((y*12+(m-1)))
exec paste <(c $((d-1))) <(c $((d))) <(c $((d+1)))

Posted by Anonymous on October 21, 2004 at 02:51 PM PDT #