added multi-select function

lib/skel/.bashrc.d/functions

@@ -225,3 +225,112 @@ select_opt(){
 #  1) echo "selected No";;
 #  *) echo "selected ${options[$?]}";;
 #esac
+
+multiselect(){
+  # little helpers for terminal print control and key input
+  ESC=$( printf "\033")
+  cursor_blink_on()   { printf "$ESC[?25h"; }
+  cursor_blink_off()  { printf "$ESC[?25l"; }
+  cursor_to()         { printf "$ESC[$1;${2:-1}H"; }
+  print_inactive()    { printf "$2   $1 "; }
+  print_active()      { printf "$2  $ESC[7m $1 $ESC[27m"; }
+  get_cursor_row()    { IFS=';' read -sdR -p $'\E[6n' ROW COL; echo ${ROW#*[}; }
+
+  local return_value=$1
+  local -n options=$2
+  local -n defaults=$3
+
+  local selected=()
+  for ((i=0; i<${#options[@]}; i++)); do
+    if [[ ${defaults[i]} = "true" ]]; then
+      selected+=("true")
+    else
+      selected+=("false")
+    fi
+    printf "\n"
+  done
+
+  # determine current screen position for overwriting the options
+  local lastrow=`get_cursor_row`
+  local startrow=$(($lastrow - ${#options[@]}))
+
+  # ensure cursor and input echoing back on upon a ctrl+c during read -s
+  trap "cursor_blink_on; stty echo; printf '\n'; exit" 2
+  cursor_blink_off
+
+  key_input() {
+    local key
+    IFS= read -rsn1 key 2>/dev/null >&2
+    if [[ $key = ""      ]]; then echo enter; fi;
+    if [[ $key = $'\x20' ]]; then echo space; fi;
+    if [[ $key = "k" ]]; then echo up; fi;
+    if [[ $key = "j" ]]; then echo down; fi;
+    if [[ $key = $'\x1b' ]]; then
+      read -rsn2 key
+      if [[ $key = [A || $key = k ]]; then echo up;    fi;
+      if [[ $key = [B || $key = j ]]; then echo down;  fi;
+    fi 
+  }
+
+  toggle_option() {
+    local option=$1
+    if [[ ${selected[option]} == true ]]; then
+      selected[option]=false
+    else
+      selected[option]=true
+    fi
+  }
+
+  print_options() {
+    # print options by overwriting the last lines
+    local idx=0
+    for option in "${options[@]}"; do
+      local prefix="[ ]"
+      if [[ ${selected[idx]} == true ]]; then
+        prefix="[\e[38;5;46m✔\e[0m]"
+      fi
+
+      cursor_to $(($startrow + $idx))
+      if [ $idx -eq $1 ]; then
+        print_active "$option" "$prefix"
+      else
+        print_inactive "$option" "$prefix"
+      fi
+      ((idx++))
+    done
+  }
+
+  local active=0
+  while true; do
+    print_options $active
+
+    # user key control
+    case `key_input` in
+      space)  toggle_option $active;;
+      enter)  print_options -1; break;;
+      up)     ((active--));
+              if [ $active -lt 0 ]; then active=$((${#options[@]} - 1)); fi;;
+      down)   ((active++));
+              if [ $active -ge ${#options[@]} ]; then active=0; fi;;
+    esac
+  done
+
+  # cursor position back to normal
+  cursor_to $lastrow
+  printf "\n"
+  cursor_blink_on
+
+  eval $return_value='("${selected[@]}")'
+}
+
+# Example for above multiselect functions
+#my_options=(   "Option 1"  "Option 2"  "Option 3" )
+#preselection=( "true"      "true"      "false"    )
+
+#multiselect result my_options preselection
+
+#idx=0
+#for option in "${my_options[@]}"; do
+#    echo -e "$option\t=> ${result[idx]}"
+#    ((idx++))
+#done