Makefile: refactor add docs and add command line help target

Author: jbampton

Makefile

@@ -11,46 +11,44 @@ define check_command
 	}
 endef
 
-all : check_rake
+.PHONY: all test clean check checkinstall checkupdate composecheck composetest check_rake check_docker_compose check_pre_commit help
+.DEFAULT_GOAL := all
+
+all: check_rake ## build all targets, install (locally) in-repo
 	$(RAKE)
-.PHONY : all
 
-test : check_rake all
+test: check_rake all ## build and run all mruby tests
 	$(RAKE) test
-.PHONY : test
 
-clean : check_rake
+clean: check_rake ## clean all built and in-repo installed artifacts
 	$(RAKE) clean
-.PHONY : clean
 
-check : check_pre_commit
+check: check_pre_commit ## run all pre-commit hooks against all files
 	$(PRE_COMMIT) run --all-files
-.PHONY : check
 
-checkinstall : check_pre_commit
+checkinstall: check_pre_commit ## install the pre-commit hooks
 	$(PRE_COMMIT) install
-.PHONY : checkinstall
 
-checkupdate : check_pre_commit
+checkupdate: check_pre_commit ## check the pre-commit hooks for updates
 	$(PRE_COMMIT) autoupdate
-.PHONY : checkupdate
 
-composecheck : check_docker_compose check_pre_commit
+composecheck: check_docker_compose check_pre_commit ## run all pre-commit hooks against all files with docker-compose
 	$(DOCKER_COMPOSE) -p mruby run test $(PRE_COMMIT) run --all-files
-.PHONY : composecheck
 
-composetest : check_docker_compose
+composetest: check_docker_compose ## build and run all mruby tests with docker-compose
 	$(DOCKER_COMPOSE) -p mruby run test
-.PHONY : composetest
 
-check_rake:
+check_rake: ## check if Rake is installed
 	$(call check_command, $(RAKE))
-.PHONY : check_rake
 
-check_docker_compose:
+check_docker_compose: ## check if docker-compose is installed
 	$(call check_command, $(DOCKER_COMPOSE))
-.PHONY : check_docker_compose
 
-check_pre_commit:
+check_pre_commit: ## check if pre-commit is installed
 	$(call check_command, $(PRE_COMMIT))
-.PHONY : check_pre_commit
+
+help: ## display this help message
+	@echo "Usage: make <target>"
+	@echo
+	@echo "Available targets:"
+	@grep -E '^[a-z_-]+:.*##' $(MAKEFILE_LIST) | sort | awk 'BEGIN {FS = ":.*## *"}; {printf "  \033[36m%-20s\033[0m %s\n", $$1, $$2}'