refactor: use ${array[@]:-}/${array[@]:+} simplify codes 🚞

bin/ap

@@ -130,7 +130,8 @@ while [ $# -gt 0 ]; do
   esac
 done
 
-[ ${#files[@]} -eq 0 ] && files=(.)
+# if files is empty, use "."
+files=("${files[@]:-.}")
 readonly files
 
 ################################################################################

bin/find-in-jars

@@ -268,9 +268,7 @@ readonly dirs
 # convert extensions to find -iname options
 find_iname_options=()
 for e in "${extensions[@]}"; do
-  (("${#find_iname_options[@]}" == 0)) &&
-    find_iname_options=(-iname "*.$e") ||
-    find_iname_options=("${find_iname_options[@]}" -o -iname "*.$e")
+  find_iname_options=(${find_iname_options[@]:+"${find_iname_options[@]}" -o} -iname "*.$e")
 done
 readonly find_iname_options
 

bin/uq

@@ -194,7 +194,7 @@ while (($# > 0)); do
     ;;
   --)
     shift
-    argv=("${argv[@]}" "$@")
+    argv=(${argv[@]:+"${argv[@]}"} "$@")
     break
     ;;
   -)

bin/xpl

@@ -66,7 +66,7 @@ progVersion() {
 # parse options
 ################################################################################
 
-declare -a args=()
+declare -a files=()
 selected=false
 while [ $# -gt 0 ]; do
   case "$1" in
@@ -82,23 +82,26 @@ while [ $# -gt 0 ]; do
     ;;
   --)
     shift
-    args=(${args[@]:+"${args[@]}"} "$@")
+    files=(${files[@]:+"${files[@]}"} "$@")
     break
     ;;
   -*)
     usage 2 "${PROG}: unrecognized option '$1'"
     ;;
   *)
-    args=(${args[@]:+"${args[@]}"} "$1")
+    files=(${files[@]:+"${files[@]}"} "$1")
     shift
     ;;
   esac
 done
 
+# if files is empty, use one element "."
+files=("${files[@]:-.}")
+
 # if program name is xpf, set option selected!
 [ "xpf" == "${PROG}" ] && selected=true
 
-readonly args selected
+readonly files selected
 
 ################################################################################
 # biz logic
@@ -143,7 +146,6 @@ openOneFile() {
   printf 'open %14s: %s\n' "$selected_msg" "$file"
 }
 
-[ "${#args[@]}" == 0 ] && files=(.) || files=("${args[@]}")
 has_error=false
 
 for file in "${files[@]}"; do

legacy-bin/swtrunk

@@ -27,7 +27,8 @@ greenEcho() {
   colorEcho 32 "$@"
 }
 
-[ $# -eq 0 ] && dirs=(.) || dirs=("$@")
+# if dirs is empty, use "."
+dirs=("${dirs[@]:-.}")
 
 for d in "${dirs[@]}"; do
   [ ! -d "${d}/.svn" ] && {