diff options
author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 15:38:56 +0000 |
---|---|---|
committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 15:38:56 +0000 |
commit | 6c20c8ed2cb9ab69a1a57ccb2b9b79969a808321 (patch) | |
tree | f63ce19d57fad3ac4a15bc26dbfbfa2b834111b5 /examples/functions/arrayops.bash | |
parent | Initial commit. (diff) | |
download | bash-upstream.tar.xz bash-upstream.zip |
Adding upstream version 5.2.15.upstream/5.2.15upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'examples/functions/arrayops.bash')
-rw-r--r-- | examples/functions/arrayops.bash | 146 |
1 files changed, 146 insertions, 0 deletions
diff --git a/examples/functions/arrayops.bash b/examples/functions/arrayops.bash new file mode 100644 index 0000000..d34353a --- /dev/null +++ b/examples/functions/arrayops.bash @@ -0,0 +1,146 @@ +# arrayops.bash --- hide some of the nasty syntax for manipulating bash arrays +# Author: Noah Friedman <friedman@splode.com> +# Created: 2016-07-08 +# Public domain + +# $Id: arrayops.bash,v 1.3 2016/07/28 15:38:55 friedman Exp $ + +# Commentary: + +# These functions try to tame the syntactic nightmare that is bash array +# syntax, which makes perl's almost look reasonable. +# +# For example the apush function below lets you write: +# +# apush arrayvar newval +# +# instead of +# +# ${arrayvar[${#arrayvar[@]}]}=newval +# +# Because seriously, you've got to be kidding me. + +# These functions avoid the use of local variables as much as possible +# (especially wherever modification occurs) because those variable names +# might shadow the array name passed in. Dynamic scope! + +# Code: + +#:docstring apush: +# Usage: apush arrayname val1 {val2 {...}} +# +# Appends VAL1 and any remaining arguments to the end of the array +# ARRAYNAME as new elements. +#:end docstring: +apush() +{ + eval "$1=(\"\${$1[@]}\" \"\${@:2}\")" +} + +#:docstring apop: +# Usage: apop arrayname {n} +# +# Removes the last element from ARRAYNAME. +# Optional argument N means remove the last N elements. +#:end docstring: +apop() +{ + eval "$1=(\"\${$1[@]:0:\${#$1[@]}-${2-1}}\")" +} + +#:docstring aunshift: +# Usage: aunshift arrayname val1 {val2 {...}} +# +# Prepends VAL1 and any remaining arguments to the beginning of the array +# ARRAYNAME as new elements. The new elements will appear in the same order +# as given to this function, rather than inserting them one at a time. +# +# For example: +# +# foo=(a b c) +# aunshift foo 1 2 3 +# => foo is now (1 2 3 a b c) +# but +# +# foo=(a b c) +# aunshift foo 1 +# aunshift foo 2 +# aunshift foo 3 +# => foo is now (3 2 1 a b c) +# +#:end docstring: +aunshift() +{ + eval "$1=(\"\${@:2}\" \"\${$1[@]}\")" +} + +#:docstring ashift: +# Usage: ashift arrayname {n} +# +# Removes the first element from ARRAYNAME. +# Optional argument N means remove the first N elements. +#:end docstring: +ashift() +{ + eval "$1=(\"\${$1[@]: -\${#$1[@]}+${2-1}}\")" +} + +#:docstring aset: +# Usage: aset arrayname idx newval +# +# Assigns ARRAYNAME[IDX]=NEWVAL +#:end docstring: +aset() +{ + eval "$1[\$2]=${@:3}" +} + +#:docstring aref: +# Usage: aref arrayname idx {idx2 {...}} +# +# Echoes the value of ARRAYNAME at index IDX to stdout. +# If more than one IDX is specified, each one is echoed. +# +# Unfortunately bash functions cannot return arbitrary values in the usual way. +#:end docstring: +aref() +{ + eval local "v=(\"\${$1[@]}\")" + local x + for x in ${@:2} ; do echo "${v[$x]}"; done +} + +#:docstring aref: +# Usage: alen arrayname +# +# Echoes the length of the number of elements in ARRAYNAME. +# +# It also returns number as a numeric value, but return values are limited +# by a maximum of 255 so don't rely on this unless you know your arrays are +# relatively small. +#:end docstring: +alen() +{ + eval echo "\${#$1[@]}" + eval return "\${#$1[@]}" +} + +#:docstring anreverse: +# Usage: anreverse arrayname +# +# Reverse the order of the elements in ARRAYNAME. +# The array variable is altered by this operation. +#:end docstring: +anreverse() +{ + eval set $1 "\"\${$1[@]}\"" + eval unset $1 + while [ $# -gt 1 ]; do + eval "$1=(\"$2\" \"\${$1[@]}\")" + set $1 "${@:3}" + done +} + +#provide arrayops + +# arrayops.bash ends here |