Use date from VC system

Make the \date command aware of the version control system by adding the
vc package (public-domain) and thus display date of last commit and not
of generation as long as a Git repository is available.

5 files changed, 130 insertions, 4 deletions

diff --git a/.gitignore b/.gitignore
index e4dd5f3..6d5cd39 100644
--- a/.gitignore
+++ b/.gitignore
@@ -10,3 +10,4 @@
 *.lox
 *.out
 *.dvi
+vc.tex
diff --git a/Makefile b/Makefile
index 774fc39..8b49437 100644
--- a/Makefile
+++ b/Makefile
@@ -3,13 +3,13 @@ html : pms.html
 
 clean :
 	rm -f *~ *.pdf *.dvi *.log *.aux *.bbl *.blg *.toc *.lol *.loa *.lox \
-	    *.lot *.out *.html *.css *.png *.4ct *.4tc *.idv *.lg *.tmp *.xref || true
+	    *.lot *.out *.html *.css *.png *.4ct *.4tc *.idv *.lg *.tmp *.xref vc.tex || true
 
 LATEXFILES = $(shell ls *.tex)
 LISTINGFILES = $(shell ls *.listing)
 SOURCEFILES = $(LATEXFILES) $(LISTINGFILES)
 
-pms.pdf: $(SOURCEFILES) pms.bbl
+pms.pdf: $(SOURCEFILES) pms.bbl vc.tex
 	pdflatex pms
 	pdflatex pms
 	pdflatex pms
@@ -27,10 +27,13 @@ pms.html: $(SOURCEFILES) pms.bbl
 	@# align algorithm line numbers properly
 	sed -i -e '/<span class="ALCitem">/{N;s/\n\(class="[^"]\+">\)\([0-9]:\)<\/span>/\1\&#x2007;\2/}' pms.html
 
-pms.bbl: pms.bib pms.tex
+pms.bbl: pms.bib pms.tex vc.tex
 	latex pms
 	bibtex pms
 
+vc.tex: pms.tex
+	/bin/sh ./vc
+
 pms.dvi: $(SOURCEFILES) pms.bbl
 	latex pms
 	latex pms
diff --git a/pms.tex b/pms.tex
index 6fd03cb..8a14f30 100644
--- a/pms.tex
+++ b/pms.tex
@@ -1,4 +1,5 @@
 \documentclass[a4paper]{report}
+\input{vc}
 % Definition of fonts, choose T1 encoding for fonts
 \usepackage[T1]{fontenc}
 %
@@ -19,6 +20,7 @@
   algorithm,
   algorithmic
 }
+\usepackage[orig,english]{isodate}
 \usepackage[DIV13]{typearea}
 \usepackage[position=top]{caption}
 \usepackage[utf8]{inputenc}
@@ -103,10 +105,17 @@
   pdfkeywords={Gentoo, package manager, specification},
   pdfproducer={pdfLaTeX and hyperref},
 }
-
 \title{Package Manager Specification}
 \author{Stephen P. Bennett\\\url{spb@exherbo.org}
 \and Ciaran McCreesh\\\url{ciaran.mccreesh@googlemail.com}}
+% Make the build succeed even when no Git repository is available
+\ifthenelse{\equal{\VCDateISO}{}}
+{
+  \date{Generated on: \today}
+}{
+  \date{\printdate{\VCDateISO}}
+}
+
 \pagestyle{myheadings}
 \markboth{\scshape Package Manager Specification}{\scshape Package
   Manager Specification}
diff --git a/vc b/vc
new file mode 100644
index 0000000..5c5a1b3
--- /dev/null
+++ b/vc
@@ -0,0 +1,24 @@
+#!/bin/sh
+# This is file 'vc' from the vc bundle for TeX.
+# The original file can be found at CTAN:support/vc.
+# This file is Public Domain.
+
+# Parse command line options.
+full=0
+mod=0
+while [ -n "$(echo $1 | grep '-')" ]; do
+    case $1 in 
+       -f ) full=1 ;;
+       -m ) mod=1 ;;
+       *  ) echo 'usage: vc [-f] [-m]'
+            exit 1
+    esac
+    shift
+done
+# English locale.
+LC_ALL=C
+git --no-pager log -1 HEAD --pretty=format:"Hash: %H%nAbr. Hash: %h%nParent Hashes: %P%nAbr. Parent Hashes: %p%nAuthor Name: %an%nAuthor Email: %ae%nAuthor Date: %ai%nCommitter Name: %cn%nCommitter Email: %ce%nCommitter Date: %ci%n" |gawk -v script=log -v full=$full -f vc-git.awk > vc.tex
+if [ "$mod" = 1 ]
+then
+  git status |gawk -v script=status -f vc-git.awk >> vc.tex
+fi
diff --git a/vc-git.awk b/vc-git.awk
new file mode 100644
index 0000000..66b3526
--- /dev/null
+++ b/vc-git.awk
@@ -0,0 +1,89 @@
+# This is file 'vc-git.awk' from the vc bundle for TeX.
+# The original file can be found at CTAN:support/vc.
+# This file is Public Domain.
+BEGIN {
+		
+### Process output of "git status".
+		if (script=="status") {
+				modified = 0
+		}
+
+}
+
+
+
+### Process output of "git log".
+script=="log" && /^Hash:/ { Hash = substr($0, 2+match($0, ":")) }
+script=="log" && /^Abr. Hash:/ { AbrHash = substr($0, 2+match($0, ":")) }
+script=="log" && /^Parent Hashes:/ { ParentHashes = substr($0, 2+match($0, ":")) }
+script=="log" && /^Abr. Parent Hashes:/ { AbrParentHashes = substr($0, 2+match($0, ":")) }
+script=="log" && /^Author Name:/ { AuthorName = substr($0, 2+match($0, ":")) }
+script=="log" && /^Author Email:/ { AuthorEmail = substr($0, 2+match($0, ":")) }
+script=="log" && /^Author Date:/ { AuthorDate = substr($0, 2+match($0, ":")) }
+script=="log" && /^Committer Name:/ { CommitterName = substr($0, 2+match($0, ":")) }
+script=="log" && /^Committer Email:/ { CommitterEmail = substr($0, 2+match($0, ":")) }
+script=="log" && /^Committer Date:/ { CommitterDate = substr($0, 2+match($0, ":")) }
+
+### Process output of "git status".
+### Changed index?
+script=="status" && /^# Changes to be committed:/ { modified = 1 }
+### Unstaged modifications?
+script=="status" && /^# Changed but not updated:/ { modified = 2 }
+
+
+
+END {
+		
+### Process output of "git log".
+		if (script=="log") {
+### Standard encoding is UTF-8.
+				if (Encoding == "") Encoding = "UTF-8"
+### Extract relevant information from variables.
+				LongDate = substr(AuthorDate, 1, 25)
+        DateRAW = substr(LongDate, 1, 10)
+        DateISO = DateRAW
+        DateTEX = DateISO
+        gsub("-", "/", DateTEX)
+				Time = substr(LongDate, 12, 14)
+### Write file identification to vc.tex.
+				print "%%% This file has been generated by the vc bundle for TeX."
+				print "%%% Do not edit this file!"
+				print "%%%"
+### Write Git specific macros.
+				print "%%% Define Git specific macros."
+				print "\\gdef\\GITHash{" Hash "}%"
+				print "\\gdef\\GITAbrHash{" AbrHash "}%"
+				print "\\gdef\\GITParentHashes{" ParentHashes "}%"
+				print "\\gdef\\GITAbrParentHashes{" AbrParentHashes "}%"
+				print "\\gdef\\GITAuthorName{" AuthorName "}%"
+				print "\\gdef\\GITAuthorEmail{" AuthorEmail "}%"
+				print "\\gdef\\GITAuthorDate{" AuthorDate "}%"
+				print "\\gdef\\GITCommitterName{" CommitterName "}%"
+				print "\\gdef\\GITCommitterEmail{" CommitterEmail "}%"
+				print "\\gdef\\GITCommitterDate{" CommitterDate "}%"
+### Write generic version control macros.
+				print "%%% Define generic version control macros."
+				print "\\gdef\\VCRevision{\\GITAbrHash}%"
+				print "\\gdef\\VCAuthor{\\GITAuthorName}%"
+        print "\\gdef\\VCDateRAW{" DateRAW "}%"
+        print "\\gdef\\VCDateISO{" DateISO "}%"
+        print "\\gdef\\VCDateTEX{" DateTEX "}%"
+				print "\\gdef\\VCTime{" Time "}%"
+				print "\\gdef\\VCModifiedText{\\textcolor{red}{with local modifications!}}%"
+				print "%%% Assume clean working copy."
+				print "\\gdef\\VCModified{0}%"
+				print "\\gdef\\VCRevisionMod{\\VCRevision}%"
+		}
+		
+### Process output of "git status".
+		if (script=="status") {
+				print "%%% Is working copy modified?"
+				print "\\gdef\\VCModified{" modified "}%"
+				if (modified==0) {
+						print "\\gdef\\VCRevisionMod{\\VCRevision}%"
+				} else {
+						print "\\gdef\\VCRevisionMod{\\VCRevision~\\VCModifiedText}%"
+				}
+		}
+		
+}