Added self-documenting comments and default Rule to list commands with descriptions

Author: niloch

{{ cookiecutter.repo_name }}/Makefile

@@ -10,24 +10,93 @@ BUCKET = {{ cookiecutter.s3_bucket }}
 # COMMANDS                                                                      #
 #################################################################################
 
+## Install Python Dependencies
 requirements:
 	pip install -q -r requirements.txt
 
+## Make Dataset
 data: requirements
 	python src/data/make_dataset.py
 
+## Delete all compiled Python files
 clean:
 	find . -name "*.pyc" -exec rm {} \;
 
+## Lint using flake8
 lint:
 	flake8 --exclude=lib/,bin/,docs/conf.py .
 
+## Upload Data to S3
 sync_data_to_s3:
 	aws s3 sync data/ s3://$(BUCKET)/data/
 
+## Download Data from S3
 sync_data_from_s3:
 	aws s3 sync s3://$(BUCKET)/data/ data/
 
 #################################################################################
 # PROJECT RULES                                                                 #
 #################################################################################
+
+
+
+#################################################################################
+# Self Documenting Commands                                                                #
+#################################################################################
+
+.DEFAULT_GOAL := show-help
+
+# Inspired by <http://marmelab.com/blog/2016/02/29/auto-documented-makefile.html>
+# sed script explained:
+# /^##/:
+# 	* save line in hold space
+# 	* purge line
+# 	* Loop:
+# 		* append newline + line to hold space
+# 		* go to next line
+# 		* if line starts with doc comment, strip comment character off and loop
+# 	* remove target prerequisites
+# 	* append hold space (+ newline) to line
+# 	* replace newline plus comments by `---`
+# 	* print line
+# Separate expressions are necessary because labels cannot be delimited by
+# semicolon; see <http://stackoverflow.com/a/11799865/1968>
+.PHONY: show-help
+show-help:
+	@echo "$$(tput bold)Available rules:$$(tput sgr0)"
+	@echo
+	@sed -n -e "/^## / { \
+		h; \
+		s/.*//; \
+		:doc" \
+		-e "H; \
+		n; \
+		s/^## //; \
+		t doc" \
+		-e "s/:.*//; \
+		G; \
+		s/\\n## /---/; \
+		s/\\n/ /g; \
+		p; \
+	}" ${MAKEFILE_LIST} \
+	| LC_ALL='C' sort --ignore-case \
+	| awk -F '---' \
+		-v ncol=$$(tput cols) \
+		-v indent=19 \
+		-v col_on="$$(tput setaf 6)" \
+		-v col_off="$$(tput sgr0)" \
+	'{ \
+		printf "%s%*s%s ", col_on, -indent, $$1, col_off; \
+		n = split($$2, words, " "); \
+		line_length = ncol - indent; \
+		for (i = 1; i <= n; i++) { \
+			line_length -= length(words[i]) + 1; \
+			if (line_length <= 0) { \
+				line_length = ncol - indent - length(words[i]) - 1; \
+				printf "\n%*s ", -indent, " "; \
+			} \
+			printf "%s ", words[i]; \
+		} \
+		printf "\n"; \
+	}' \
+	| more $(shell test $(shell uname) == Darwin && echo '--no-init --raw-control-chars')