container: plugins: refactor example plugin

- Refactor instance
- Refactor main()

container/plugins/finance/example.bash

@@ -38,9 +38,12 @@
 [ -z "$DOCKER_FINANCE_CONTAINER_REPO" ] && exit 1
 source "${DOCKER_FINANCE_CONTAINER_REPO}/src/finance/lib/lib_finance.bash"
 
+[[ -z "$global_parent_profile" || -z "$global_arg_delim_1" || -z "$global_child_profile" ]] && lib_utils::die_fatal
+instance="${global_parent_profile}${global_arg_delim_1}${global_child_profile}"
+
 # Initialize "constructor"
-[[ -z "$global_parent_profile" || -z "$global_arg_delim_1" || -z "$global_child_profile" ]] && exit 1
-lib_finance::finance "${global_parent_profile}${global_arg_delim_1}${global_child_profile}"
+# NOTE: "constructor" only needed if calling library directly
+lib_finance::finance "$instance" || lib_utils::die_fatal
 
 #
 # Implementation
@@ -48,14 +51,14 @@ lib_finance::finance "${global_parent_profile}${global_arg_delim_1}${global_chil
 
 function main()
 {
-  echo -e "
+  local -r _example="
 This container's environment:
 
 $(printenv | grep ^DOCKER_FINANCE | sort)
 
 This plugin's caller profile:
 
-    ${global_parent_profile}${global_arg_delim_1}${global_child_profile}
+    $instance
 
 This plugin's path is:
 
@@ -66,10 +69,11 @@ This plugin's arguments:
     '${*}'
 
 Showing total current BTC balance:
+
+  $(lib_finance::ledger bal assets liabilities cur:BTC | tail -n1)
+
 "
-  echo -n "    "
-  lib_finance::ledger bal assets liabilities cur:BTC | tail -n1
-  echo
+  lib_utils::print_custom "$_example"
 }
 
 main "$@"