#!/bin/sh -u
# Pluralize the string if the number is not one.
# Syntax:
#   $0 number string
# Purpose:
#  If the number is not singular, output the string with an "s" on the end.
#  This knows nothing about English spelling, so it will make mistakes
#  on many plurals (e.g. mouse, box, concerto, etc.).
# -IAN! idallen@ncf.ca

# Set the search path for the shell to be the standard places.
# Set the umask to be non-restrictive and friendly to others.
#
PATH=/bin:/usr/bin ; export PATH
umask 022

if [ $# -ne 2 ] ; then
    echo 1>&2 "$0: Expecting number and string, found $# arguments ($*)"
    exit 2
fi

# Transfer the two arguments to named variables to improve readability.
#
number="$1"
string="$2"

# The IsNumeric function tests its argument to see if it is a valid number.
# It sets the return/exit status to zero if it is a number, to nonzero if not.
#
IsNumeric () {
    # Make sure this function is called with exactly one argument.
    #
    if [ $# -ne 1 ] ; then
        echo 1>&2 "$0 IsNumeric: Expecting one function argument; found $# ($*)"
        exit 2
    fi

    # The expr command sets a return code of 2 on a syntax error or
    # bad (non-numeric) input.  Throw away all the output and errors;
    # look at the return status only.
    #
    [ "$1" = '-' ] && return 1 # compensate for non-number bug in expr
    expr 0 + "$1" >/dev/null 2>&1
    test "$?" -ne 2   # set return code to 0 if true
}

# See if the number really is numeric.
#
if ! IsNumeric "$number" ; then
    echo 1>&2 "$0: Number '$number' is not an integer; nothing done"
    exit 2
fi

# See if the string is not empty.
#
if [ -z "$string" ] ; then
    echo 1>&2 "$0: String is empty; nothing done"
    exit 2
fi

# pseudo-English pluralization
#
if [ $number -eq 1 -o $number -eq -1 ] ; then
    plural=''
else
    plural='s'
fi

echo "${string}${plural}"

exit 0