jens-maus/yam

#! /bin/sh
: 'Determine whether year is of appropriate type (this file is obsolete).'

: 'This file is in the public domain, so clarified as of'
: '2006-07-17 by Arthur David Olson.'

case $#-$1 in
    2-|2-0*|2-*[!0-9]*)
        echo "$0: wild year: $1" >&2
        exit 1 ;;
esac

case $#-$2 in
    2-even)
        case $1 in
            *[24680])            exit 0 ;;
            *)                exit 1 ;;
        esac ;;
    2-nonpres|2-nonuspres)
        case $1 in
            *[02468][048]|*[13579][26])    exit 1 ;;
            *)                exit 0 ;;
        esac ;;
    2-odd)
        case $1 in
            *[13579])            exit 0 ;;
            *)                exit 1 ;;
        esac ;;
    2-uspres)
        case $1 in
            *[02468][048]|*[13579][26])    exit 0 ;;
            *)                exit 1 ;;
        esac ;;
    2-*)
        echo "$0: wild type: $2" >&2 ;;
esac

echo "$0: usage is $0 year even|odd|uspres|nonpres|nonuspres" >&2
exit 1