[Makefile Help Target]: Self-Describing Makefile

self-describing-makefile.mk

# self describing makefile
#    based on idea in https://gist.github.com/jeffsp/3e1b2e10b9181681a604dd9ec6d64ecf
#
# add support for any Makefile name, see https://www.gnu.org/software/make/manual/make.html#Special-Variables
# add colon after target name so bat -l mk gives nicer display on terminal
# for nicer Markdown add asterix around \1 in sed, e.g. for bat or mdcat
#
# Usage
# ==========
#
# Example 1: No post-processing
#    make --file self-describing-makefile.mk
#
# Example 2: Using the current grep/sed w/o the asterix:
#
#    make --file self-describing-makefile.mk | bat -l mk
#
# Example 3: Change grep+sed to two asterix around the \1 turns into **\1**
#
#    make --file self-describing-makefile.mk | mdcat
#    make --file self-describing-makefile.mk | bat -l md
#

# Get name of Makefile so the grep picks the right one
name1 := $(lastword $(MAKEFILE_LIST))

# Set help as the default goal
.DEFAULT_GOAL := help

.PHONY: target1 # Target 1 help text
target1: target2 target3
	@echo "Target 1, the name of the makefile is: $(name1)"

.PHONY: target2 # Target 2 help text
target2:
	@echo "Target 2"

.PHONY: target3
target3:
	@echo "No help for this target"

.PHONY: help # Generate list of targets with descriptions
help:
	@grep '^.PHONY: .* #' "$(name1)" | sed 's/\.PHONY: \(.*\) # \(.*\)/\1: \2/' | expand -t20