i-bash/examples/functions/seq2
2009-09-12 16:46:52 +00:00

37 lines
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Text

# Generate a sequence from m to n, m defaults to 1.
seq ()
{
declare -i lo hi i # makes local
local _SEQ INIT COMPARE STEP
case "$1" in
-r) INIT='i=$hi _SEQ=""' COMPARE='let "i >= $lo"' STEP='let i-=1' ; shift ;;
*) INIT='i=$lo _SEQ=""' COMPARE='let "i <= $hi"' STEP='let i+=1' ;;
esac
case $# in
1) lo=1 hi="$1" ;;
2) lo=$1 hi=$2 ;;
*) echo seq: usage: seq [-r] [low] high 1>&2 ; return 2 ;;
esac
# equivalent to the as-yet-unimplemented
# for (( "$INIT" ; "$COMPARE" ; "$STEP" )); do _SEQ="${_SEQ}$i "; done
eval "$INIT"
while eval "$COMPARE"; do
_SEQ="${_SEQ}$i "
eval "$STEP"
done
echo "${_SEQ# }"
return 0
}
# like the APL `iota' function (or at least how I remember it :-)
iota()
{
case $# in
1) seq 1 "$1"; return $?;;
*) echo "iota: usage: iota high" 1>&2; return 2;;
esac
}