shorten

Signed-off-by: Harmen Stoppels <me@harmenstoppels.nl>

Author: haampie

cc.sh

@@ -114,91 +114,72 @@ append() {
     fi
 }
 
-# extend LISTNAME1 LISTNAME2 [PREFIX]
+# extend DST_LISTNAME SRC_LISTNAME [PREFIX]
 #
-# Append the elements stored in the variable LISTNAME2
-# to the list stored in LISTNAME1.
+# Append the elements stored in the variable SRC_LISTNAME
+# to the list stored in DST_LISTNAME.
 # If PREFIX is provided, prepend it to each element.
 extend() {
-    _listname="$1"
-    _src_list="$2"
+    _dst="$1"
+    _src="$2"
     _prefix="$3"
 
-    setsep "$_src_list"
-    if [ "$sep" != " " ]; then
-        IFS="$sep"
-    fi
-    # Turn list into positional parameters
-    eval "set -- \${$_src_list}"
+    # Turn source list into positional parameters
+    setsep "$_src"
+    [ "$sep" != " " ] && IFS="$sep"
+    eval "set -- \${$_src}"
     unset IFS
 
-    if [ $# -eq 0 ]; then
-        return
-    fi
+    [ $# -eq 0 ] && return
 
-    setsep "$_listname"
-    _target_sep="$sep"
+    setsep "$_dst"; _dst_sep="$sep"
 
     if [ -z "$_prefix" ]; then
-        IFS="$_target_sep"
-        _ext_str="$*"
-        unset IFS
+        # Fast concatenation when no prefix is needed
+        IFS="$_dst_sep"; _ext_str="$*"; unset IFS
     else
         _ext_str="${_prefix}$1"
         shift
         for elt in "$@"; do
-            _ext_str="${_ext_str}${_target_sep}${_prefix}${elt}"
+            _ext_str="${_ext_str}${_dst_sep}${_prefix}${elt}"
         done
     fi
 
-    if empty "$_listname"; then
-        eval "$_listname=\"\${_ext_str}\""
-    else
-        eval "$_listname=\"\${$_listname}${_target_sep}\${_ext_str}\""
-    fi
+    eval "$_dst=\"\${$_dst:+\${$_dst}$_dst_sep}\${_ext_str}\""
 }
 
-# preextend LISTNAME1 LISTNAME2 [PREFIX]
+# preextend DST_LISTNAME SRC_LISTNAME [PREFIX]
 #
-# Prepend the elements stored in the list at LISTNAME2
-# to the list at LISTNAME1, preserving order.
+# Prepend the elements stored in the list at SRC_LISTNAME
+# to the list at DST_LISTNAME, preserving order.
 # If PREFIX is provided, prepend it to each element.
 preextend() {
-    _listname="$1"
-    _src_list="$2"
+    _dst="$1"
+    _src="$2"
     _prefix="$3"
 
-    setsep "$_src_list"
-    if [ "$sep" != " " ]; then
-        IFS="$sep"
-    fi
-    eval "set -- \${$_src_list}"
+    # Turn source list into positional parameters
+    setsep "$_src"
+    [ "$sep" != " " ] && IFS="$sep"
+    eval "set -- \${$_src}"
     unset IFS
 
-    if [ $# -eq 0 ]; then
-        return
-    fi
+    [ $# -eq 0 ] && return
 
-    setsep "$_listname"
-    _target_sep="$sep"
+    setsep "$_dst"; _dst_sep="$sep"
 
     if [ -z "$_prefix" ]; then
-        IFS="$_target_sep"
-        _ext_str="$*"
-        unset IFS
+        # Fast concatenation when no prefix is needed
+        IFS="$_dst_sep"; _ext_str="$*"; unset IFS
     else
         _ext_str="${_prefix}$1"
         shift
         for elt in "$@"; do
-            _ext_str="${_ext_str}${_target_sep}${_prefix}${elt}"
+            _ext_str="${_ext_str}${_dst_sep}${_prefix}${elt}"
         done
     fi
 
-    if empty "$_listname"; then
-        eval "$_listname=\"\${_ext_str}\""
-    else
-        eval "$_listname=\"\${_ext_str}${_target_sep}\${$_listname}\""
-    fi
+    eval "$_dst=\"\${_ext_str}\${$_dst:+$_dst_sep\${$_dst}}\""
 }
 
 # END list functions