Simplify Makefile

Makefile

-# Name of the filter file, *with* `.lua` file extension.
-FILTER_FILE := $(wildcard *.lua)
-# Name of the filter, *without* `.lua` file extension
-FILTER_NAME = $(patsubst %.lua,%,$(FILTER_FILE))
-
-# Allow to use a different pandoc binary, e.g. when testing.
+# Allow to use a different pandoc binary, e.g. when testing
 PANDOC ?= pandoc
+
 # Allow to adjust the diff command if necessary
 DIFF = diff
 
+# Use a POSIX sed with ERE ('v' is specific to GNU sed)
+SED := sed $(shell sed v </dev/null >/dev/null 2>&1 && echo " --posix") -E
+
+# Name of the filter file, *with* `.lua` file extension
+FILTER_FILE := $(wildcard *.lua)
+
+# Name of the filter, *without* `.lua` file extension
+FILTER_NAME = $(patsubst %.lua,%,$(FILTER_FILE))
+
 # Directory containing the Quarto extension
 QUARTO_EXT_DIR = _extensions/$(FILTER_NAME)
+
 # The extension's name. Used in the Quarto extension metadata
 EXT_NAME = $(FILTER_NAME)
-# Current version, i.e., the latest tag. Used to version the quarto
-# extension.
+
+# Current version (the latest tag). Used for quarto extension
 VERSION = $(shell git tag --sort=-version:refname --merged | head -n1 | \
 						 sed -e 's/^v//' | tr -d "\n")
 ifeq "$(VERSION)" ""
 VERSION = 0.0.0
 endif
 
-# GitHub repository; used to setup the filter.
+# GitHub repository; used to setup the filter
 REPO_PATH = $(shell git remote get-url origin | sed -e 's%.*github\.com[/:]%%')
 REPO_NAME = $(shell git remote get-url origin | sed -e 's%.*/%%')
 USER_NAME = $(shell git config user.name)
 
-# Test that running the filter on the sample input document yields
-# the expected output.
-#
-# The automatic variable `$<` refers to the first dependency
-# (i.e., the filter file).
+## Show available targets
+# Comments preceding "simple" targets (those which do not user macro
+# name) and introduced by two dashes are used as their describtion.
+.PHONY: help
+help:
+	@tabs 22 ; $(SED) -ne \
+	'/^## / h ; /^[^.$$#][^ ]+:/ { G; s/^(.*):.*##(.*)/\1@\2/; P ; h }' \
+	$(MAKEFILE_LIST) | tr @ '\t'
+
+## Test that running the filter on the sample input yields expected output
+.PHONY: test
 test: $(FILTER_FILE) test/input.md test/test.yaml
 	$(PANDOC) --defaults test/test.yaml | \
 		$(DIFF) test/expected.native -
 
-# Ensure that the `test` target is run each time it's called.
-.PHONY: test
-
-# Re-generate the expected output. This file **must not** be a
-# dependency of the `test` target, as that would cause it to be
-# regenerated on each run, making the test pointless.
+## Re-generate the expected test output
+# This file **must not** be a dependency of the `test` target, as that
+# would cause it to be regenerated on each run, making the test
+# pointless.
 test/expected.native: $(FILTER_FILE) test/input.md test/test.yaml
 	$(PANDOC) --defaults test/test.yaml --output=$@
 
-#
-# Website
-#
-.PHONY: website
-website: _site/index.html _site/$(FILTER_FILE)
-
-_site/index.html: README.md test/input.md $(FILTER_FILE) .tools/docs.lua \
-		_site/output.md _site/style.css
-	@mkdir -p _site
-	$(PANDOC) \
-	    --standalone \
-	    --lua-filter=.tools/docs.lua \
-	    --metadata=sample-file:test/input.md \
-	    --metadata=result-file:_site/output.md \
-	    --metadata=code-file:$(FILTER_FILE) \
-	    --css=style.css \
-	    --toc \
-	    --output=$@ $<
-
-_site/style.css:
-	@mkdir -p _site
-	curl \
-	    --output $@ \
-	    'https://cdn.jsdelivr.net/gh/kognise/water.css@latest/dist/light.css'
-
-_site/output.md: $(FILTER_FILE) test/input.md test/test.yaml
-	@mkdir -p _site
-	$(PANDOC) \
-	    --defaults=test/test.yaml \
-	    --to=markdown \
-	    --output=$@
-
-_site/$(FILTER_FILE): $(FILTER_FILE)
-	@mkdir -p _site
-	(cd _site && ln -sf ../$< $<)
-
-#
-# Quarto extension
-#
-
-# Creates or updates the quarto extension
+## Creates or updates the quarto extension
 .PHONY: quarto-extension
 quarto-extension: $(QUARTO_EXT_DIR)/_extension.yml \
 		$(QUARTO_EXT_DIR)/$(FILTER_FILE)
@@ -100,46 +70,13 @@ $(QUARTO_EXT_DIR)/_extension.yml: _extensions/$(FILTER_NAME)
 	@printf 'version: %s\n'  "$(VERSION)" >> $@
 	@printf 'contributes:\n  filters:\n    - %s\n' $(FILTER_FILE) >> $@
 
-## The filter file must be below the quarto _extensions folder: a
-## symlink in the extension would not work due to the way in which
-## quarto installs extensions.
-$(QUARTO_EXT_DIR)/$(FILTER_FILE): $(FILTER_FILE) $(QUARTO_EXT_DIR)
-	if [ ! -L $(FILTER_FILE) ]; then \
-	    mv $(FILTER_FILE) $(QUARTO_EXT_DIR)/$(FILTER_FILE) && \
-	    ln -s $(QUARTO_EXT_DIR)/$(FILTER_FILE) $(FILTER_FILE); \
-	fi
-
-#
-# Release
-#
+## Sets a new release
 .PHONY: release
 release: quarto-extension
 	git commit -am "Release $(FILTER_NAME) $(VERSION)"
 	git tag v$(VERSION) -m "$(FILTER_NAME) $(VERSION)"
 
-#
-# Update filter name
-#
-.PHONY: update-name
-update-name:
-	sed -i'' -e 's/greetings/$(FILTER_NAME)/g' README.md
-	sed -i'' -e 's/greetings/$(FILTER_NAME)/g' test/test.yaml
-
-setup:
-	git mv greetings.lua $(REPO_NAME).lua
-	@# Crude method to updates the examples and links; removes the
-	@# template instructions from the README.
-	sed -i'' \
-	    -e 's/greetings/$(REPO_NAME)/g' \
-	    -e 's#tarleb/lua-filter-template#$(REPO_PATH)#g' \
-      -e '/^\* \*/,/^\* \*/d' \
-	    README.md
-	sed -i'' -e 's/greetings/$(REPO_NAME)/g' test/test.yaml
-	sed -i'' -e 's/Albert Krewinkel/$(USER_NAME)/' LICENSE
-
-#
-# Clean
-#
+## Clean unnecessary files
 .PHONY: clean
 clean:
-	rm -f _site/output.md _site/index.html _site/style.css
+	rm -f *~