Add help command to Makefile (#370)

his PR adds some love to Makefile. It introduces a new help target, which dynamically builds usage output, with textual description of what target does. It supports ANSI colors and categories. It assumes that perl is installed in the system.

Makefile

@@ -1,10 +1,36 @@
-.PHONY: statusgo all test xgo clean
+.PHONY: statusgo all test xgo clean help
 .PHONY: statusgo-android statusgo-ios
 
 GOBIN = build/bin
 GO ?= latest
 
-statusgo:
+# This is a code for automatic help generator.
+# It supports ANSI colors and categories.
+# To add new item into help output, simply add comments
+# starting with '##'. To add category, use @category.
+GREEN  := $(shell tput -Txterm setaf 2)
+WHITE  := $(shell tput -Txterm setaf 7)
+YELLOW := $(shell tput -Txterm setaf 3)
+RESET  := $(shell tput -Txterm sgr0)
+HELP_FUN = \
+		   %help; \
+		   while(<>) { push @{$$help{$$2 // 'options'}}, [$$1, $$3] if /^([a-zA-Z\-]+)\s*:.*\#\#(?:@([a-zA-Z\-]+))?\s(.*)$$/ }; \
+		   print "Usage: make [target]\n\n"; \
+		   for (sort keys %help) { \
+			   print "${WHITE}$$_:${RESET}\n"; \
+			   for (@{$$help{$$_}}) { \
+				   $$sep = " " x (32 - length $$_->[0]); \
+				   print "  ${YELLOW}$$_->[0]${RESET}$$sep${GREEN}$$_->[1]${RESET}\n"; \
+			   }; \
+			   print "\n"; \
+		   }
+
+help: ##@other Show this help
+	@perl -e '$(HELP_FUN)' $(MAKEFILE_LIST)
+
+# Main targets
+
+statusgo: ##@build Build status-go as statusd server
 	build/env.sh go build -i -o $(GOBIN)/statusd -v $(shell build/testnet-flags.sh) ./cmd/statusd
 	@echo "\nCompilation done.\nRun \"build/bin/statusd help\" to view available commands."
 
@@ -12,15 +38,15 @@ statusgo-cross: statusgo-android statusgo-ios
 	@echo "Full cross compilation done."
 	@ls -ld $(GOBIN)/statusgo-*
 
-statusgo-android: xgo
+statusgo-android: xgo ##@cross-compile Build status-go for Android
 	build/env.sh $(GOBIN)/xgo --image farazdagi/xgo --go=$(GO) -out statusgo --dest=$(GOBIN) --targets=android-16/aar -v $(shell build/testnet-flags.sh) ./cmd/statusd
 	@echo "Android cross compilation done."
 
-statusgo-ios: xgo
+statusgo-ios: xgo	##@cross-compile Build status-go for iOS
 	build/env.sh $(GOBIN)/xgo --image farazdagi/xgo --go=$(GO) -out statusgo --dest=$(GOBIN) --targets=ios-9.3/framework -v $(shell build/testnet-flags.sh) ./cmd/statusd
 	@echo "iOS framework cross compilation done."
 
-statusgo-ios-simulator: xgo
+statusgo-ios-simulator: xgo	##@cross-compile Build status-go for iOS Simulator
 	@build/env.sh docker pull farazdagi/xgo-ios-simulator
 	build/env.sh $(GOBIN)/xgo --image farazdagi/xgo-ios-simulator --go=$(GO) -out statusgo --dest=$(GOBIN) --targets=ios-9.3/framework -v $(shell build/testnet-flags.sh) ./cmd/statusd
 	@echo "iOS framework cross compilation done."
@@ -55,7 +81,7 @@ ci: mock
 	build/env.sh go test -timeout 40m -v ./extkeys
 	build/env.sh go test -timeout 1m -v ./helpers/...
 
-generate:
+generate: ##@other Regenerate assets and other auto-generated stuff
 	cp ./node_modules/web3/dist/web3.js ./static/scripts/web3.js
 	build/env.sh go generate ./static
 	rm ./static/scripts/web3.js
@@ -67,7 +93,7 @@ lint-deps:
 lint-cur:
 	gometalinter --disable-all --enable=deadcode extkeys cmd/... geth/... | grep -v -f ./static/config/linter_exclude_list.txt || echo "OK!"
 
-lint:
+lint: ##@tests Run meta linter on code
 	@echo "Linter: go vet\n--------------------"
 	@gometalinter --disable-all --enable=vet extkeys cmd/... geth/... | grep -v -f ./static/config/linter_exclude_list.txt || echo "OK!"
 	@echo "Linter: go vet --shadow\n--------------------"
@@ -114,10 +140,10 @@ lint:
 mock-install:
 	go get -u github.com/golang/mock/mockgen
 
-mock: mock-install
+mock: mock-install ##@other Regenerate mocks
 	mockgen -source=geth/common/types.go -destination=geth/common/types_mock.go -package=common
 
-test:
+test: ##@tests Run tests
 	@build/env.sh echo "mode: set" > coverage-all.out
 	build/env.sh go test -coverprofile=coverage.out -covermode=set ./geth/api
 	@build/env.sh tail -n +2 coverage.out >> coverage-all.out
@@ -171,6 +197,6 @@ test-cmd:
 	@build/env.sh go tool cover -html=coverage.out -o coverage.html
 	@build/env.sh go tool cover -func=coverage.out
 
-clean:
+clean: ##@other Cleanup
 	rm -fr build/bin/*
 	rm coverage.out coverage-all.out coverage.html