Pull metadata from git

example/.gitignore

@@ -2,3 +2,4 @@ example.aux
 example.log
 example.out
 example.pdf
+meta.tex

example/Makefile

 export TEXMFHOME ?= ../texmf
 
-example.pdf: example.tex
+GITVERSION := $(shell git log -1 --date=short --pretty=%h)
+GITDATE := $(shell git log -1 --date=short --pretty=%ad)
+GITSTATUS := $(shell git status --porcelain)
+ifneq "$(GITSTATUS)" ""
+	GITDIRTY = -dirty
+endif
+
+example.pdf: example.tex meta.tex
 	xelatex example
 	xelatex example
+
+.FORCE:
+
+meta.tex: Makefile .FORCE
+	rm -f $@
+	echo '% GENERATED FILE -- edit this in the Makefile' >>$@
+	/bin/echo '\\newcommand{\\vcsRevision}{$(GITVERSION)$(GITDIRTY)}' >>$@
+	/bin/echo '\\newcommand{\\vcsDate}{$(GITDATE)}' >>$@

example/example.tex

 \documentclass{astron}
+\input{meta}
 
 \setDocTitle{Example Document}
 \setDocNumber{1}
-\setDocRevision{1}
-\setDocDate{\today}
+\setDocRevision{\vcsRevision}
+\setDocDate{\vcsDate}
 \setDocClass{Limited}
 \setDocProgram{SDC}