summaryrefslogtreecommitdiffstats
path: root/examples/functions/arrayops.bash
diff options
context:
space:
mode:
authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 15:38:56 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 15:38:56 +0000
commit6c20c8ed2cb9ab69a1a57ccb2b9b79969a808321 (patch)
treef63ce19d57fad3ac4a15bc26dbfbfa2b834111b5 /examples/functions/arrayops.bash
parentInitial commit. (diff)
downloadbash-6c20c8ed2cb9ab69a1a57ccb2b9b79969a808321.tar.xz
bash-6c20c8ed2cb9ab69a1a57ccb2b9b79969a808321.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.bash146
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