include git revision hash and date

Makefile

@@ -1,3 +1,10 @@
-paia.html: paia.md template.html references.bib
-	pandoc -N --bibliography=references.bib --template=template --toc -5 -o paia.html paia.md 
-	perl -p -i -e 's!(http://[^<]+)\.</p>!<a href="$$1"><code class="url">$$1</code></a>.</p>!g' paia.html
+REVHASH=$(shell git log -1 --format="%H" paia.md)
+REVDATE=$(shell git log -1 --format="%ad" --date=short paia.md)
+
+paia.html: paia.md template.html5 references.bib
+	sed s/GIT_REVISION_DATE/${REVDATE}/ paia.md \
+	| pandoc -N --bibliography=references.bib --template=template --toc -f markdown -t html5 -- \
+	| perl -p -e 's!(http://[^<]+)\.</p>!<a href="$$1"><code class="url">$$1</code></a>.</p>!g' \
+	| sed 's!GIT_REVISION_HASH!<a href="https://github.com/gbv/paia/commit/${REVHASH}">${REVHASH}<\/a>!' > paia.html
+
+

paia.md

@@ -1,7 +1,6 @@
 % Patrons Account Information API (PAIA)
 % Jakob Voß
-% 2012-05-22
-
+% GIT_REVISION_DATE
 
 # Introduction
 
@@ -20,7 +19,9 @@ based on use cases and taking into account existing related standards and
 products such as NISO Circulation Interchange Protocol (NCIP), \[X]SLNP,
 DLF-ILS recommendations, and ViFind ILS drivers.
 
-Updates and sources can be found at <http://github.com/gbv/paia>.
+Updates and sources can be found at <http://github.com/gbv/paia>. The current
+version of this document was last modified at GIT_REVISION_DATE with revision
+GIT_REVISION_HASH.
 
 
 ## Conformance requirements