name: cd-history
description:
	Test someone's CD history package (uses arrays)
stdin:
	# go to known place before doing anything
	cd /
	
	alias cd=_cd
	function _cd
	{
		typeset -i cdlen i
		typeset t
	
		if [ $# -eq 0 ]
		then
			set -- $HOME
		fi
	
		if [ "$CDHISTFILE" -a -r "$CDHISTFILE" ] # if directory history exists
		then
			typeset CDHIST
			i=-1
			while read -r t			# read directory history file
			do
				CDHIST[i=i+1]=$t
			done <$CDHISTFILE
		fi
	
		if [ "${CDHIST[0]}" != "$PWD" -a "$PWD" != "" ]
		then
			_cdins				# insert $PWD into cd history
		fi
	
		cdlen=${#CDHIST[*]}			# number of elements in history
	
		case "$@" in
		-)					# cd to new dir
			if [ "$OLDPWD" = "" ] && ((cdlen>1))
			then
				'print' ${CDHIST[1]}
				'cd' ${CDHIST[1]}
				_pwd
			else
				'cd' $@
				_pwd
			fi
			;;
		-l)					# print directory list
			typeset -R3 num
			((i=cdlen))
			while (((i=i-1)>=0))
			do
				num=$i
				'print' "$num ${CDHIST[i]}"
			done
			return
			;;
		-[0-9]|-[0-9][0-9])			# cd to dir in list
			if (((i=${1#-})<cdlen))
			then
				'print' ${CDHIST[i]}
				'cd' ${CDHIST[i]}
				_pwd
			else
				'cd' $@
				_pwd
			fi
			;;
		-*)					# cd to matched dir in list
			t=${1#-}
			i=1
			while ((i<cdlen))
			do
				case ${CDHIST[i]} in
				*$t*)
					'print' ${CDHIST[i]}
					'cd' ${CDHIST[i]}
					_pwd
					break
					;;
				esac
				((i=i+1))
			done
			if ((i>=cdlen))
			then
				'cd' $@
				_pwd
			fi
			;;
		*)					# cd to new dir
			'cd' $@
			_pwd
			;;
		esac
	
		_cdins					# insert $PWD into cd history
	
		if [ "$CDHISTFILE" ]
		then
			cdlen=${#CDHIST[*]}		# number of elements in history
	
			i=0
			while ((i<cdlen))
			do
				'print' -r ${CDHIST[i]}	# update directory history
				((i=i+1))
			done >$CDHISTFILE
		fi
	}
	
	function _cdins					# insert $PWD into cd history
	{						# meant to be called only by _cd
		typeset -i i
	
		((i=0))
		while ((i<${#CDHIST[*]}))		# see if dir is already in list
		do
			if [ "${CDHIST[$i]}" = "$PWD" ]
			then
				break
			fi
			((i=i+1))
		done
	
		if ((i>22))				# limit max size of list
		then
			i=22
		fi
	
		while (((i=i-1)>=0))			# bump old dirs in list
		do
			CDHIST[i+1]=${CDHIST[i]}
		done
	
		CDHIST[0]=$PWD				# insert new directory in list
	}
	
	
	function _pwd
	{
		if [ -n "$ECD" ]
		then
			pwd 1>&6
		fi
	}
	# Start of test
	cd /tmp
	cd /bin
	cd /etc
	cd -
	cd -2
	cd -l
expected-stdout:
	/bin
	/tmp
	  3 /
	  2 /etc
	  1 /bin
	  0 /tmp
---