added conditional prompt function

rtenets

@@ -77,10 +77,23 @@ alt_var() {
     if is_set "${variable}"; then
         printf "%s" "$(eval "printf \"%s\" \"\${${variable}}\"")"
     else
-        printf "%s" "$value_if_unset"
+        printf "%s" "${value_if_unset}"
     fi
 }
 
+# Enter value if unset
+cond_enter() {
+    local input="$1"
+    local var_name="$2"
+    local value="$(alt_var "" "${var_name}")"
+
+    if [[ "${value}" == "" ]]; then
+        value="$(enter "${input}")"
+    fi
+
+    printf "%s" "${value}"
+}
+
 # Check that command exists
 has_command() {
     command -v "$1" >/dev/null 2>&1