portable makefile

3 files changed, 18 insertions, 16 deletions

diff --git a/Makefile b/Makefile
index f5f30d3..258580a 100644
--- a/Makefile
+++ b/Makefile
@@ -1,23 +1,31 @@
+.POSIX:
+.SUFFIXES:
+.SUFFIXES: .md .html
+
+# commands
+GIT = git
+PANDOC = pandoc
+PDFINFO = pdfinfo
+
+# input files
 SRC = index.md vs-c.md tagged-unions.md types.md safety.md errors.md syntax.md LICENSE.md
-HTML = $(SRC:%.md=%.html)
+HTML = $(SRC:.md=.html)
 
 spec.pdf: $(HTML)
-	if git describe --tags --exact-match 2>/dev/null; \
+	if $(GIT) describe --tags --exact-match 2>/dev/null; \
 	then \
-		metadata="subtitle=$(git describe --tags --exact-match)"; \
+		metadata="subtitle=$$($(GIT) describe --tags --exact-match)"; \
 	else \
-		metadata="version=$(git log -1 --no-decorate --oneline)"; \
+		metadata="version=$$($(GIT) log -1 --no-decorate --oneline)"; \
 	fi; \
-	pandoc --defaults=etc/pdf.yml -M "$$metadata" -o $@ $(HTML)
+	$(PANDOC) --defaults=etc/pdf.yml -M "$$metadata" -o $@ $(HTML)
 
-%.html: %.md
+.md.html:
 	offset=`echo $(SRC) | awk '{for (i=1; i<=NF; i++) if ($$i == "$<") print (i-1) }'`; \
-	pandoc --defaults=etc/md.yml --number-offset=$$offset -o $@ $<
+	$(PANDOC) --defaults=etc/md.yml --number-offset=$$offset -o $@ $<
 
 clean:
 	rm -f $(HTML) spec.pdf
 
 check: spec.pdf
-	test $$(pdfinfo spec.pdf | grep Pages | awk '{ print $$2 }') -le 200
-
-.PHONY: clean check
+	test $$($(PDFINFO) spec.pdf | grep Pages | awk '{ print $$2 }') -le 200
diff --git a/etc/md.yml b/etc/md.yml
index a918de3..52cdcfa 100644
--- a/etc/md.yml
+++ b/etc/md.yml
@@ -1,6 +1,3 @@
-from: markdown
-to: html5
-
 template: etc/template.html
 standalone: true
 
diff --git a/etc/pdf.yml b/etc/pdf.yml
index a76afca..85750bf 100644
--- a/etc/pdf.yml
+++ b/etc/pdf.yml
@@ -1,6 +1,3 @@
-from: html
-to: pdf
-
 template: etc/template.html
 
 filters: