[build] add a basic template mechanism

this grabs the {parrot,rakudo,nqp} revisions and fudges them into Configure.pl,
so at least it is one less location to update

3 files changed, 69 insertions, 3 deletions

diff --git a/Makefile b/Makefile
index f51e854..aead8c9 100644
--- a/Makefile
+++ b/Makefile
@@ -66,6 +66,7 @@ always:
 $(DISTDIR): always
 	mkdir -p $(DISTDIR)
 	cp -av skel/. $(DISTDIR)
+	perl build/skel-template.pl $(DISTDIR)
 
 $(PARROT_DIR): $(PARROT_TGZ)
 	tar -C $(DISTDIR) -xvzf $(PARROT_TGZ)
diff --git a/build/skel-template.pl b/build/skel-template.pl
new file mode 100644
index 0000000..8940d33
--- /dev/null
+++ b/build/skel-template.pl
@@ -0,0 +1,53 @@
+use strict;
+use warnings;
+
+my $destination = shift(@ARGV) || die "Usage: $0 <destination>";
+unless (-d $destination) {
+    die "Destination '$destination' should be a directory, but is not";
+}
+
+my %look_for = (PARROT_VER => 1,  RAKUDO_VER => 1,  NQP_VER => 1);
+my %vars;
+
+open my $fh, '<', 'Makefile'
+    or die "Cannot open Makefile for reading: $!";
+
+while (<$fh>) {
+    chomp;
+    if (/^(\w+)\s*=\s*(\S*)/ && $look_for{$1}) {
+        delete $look_for{$1};
+        $vars{$1} = $2;
+        last unless %look_for;
+    }
+}
+close $fh;
+if (%look_for) {
+    die "Couldn't find a definition for the following variable(s) in Makfile\n"
+        . join(', ', keys %look_for) . "\n";
+}
+
+my $subst_re = join '|', map quotemeta, keys %vars;
+$subst_re = qr{\<($subst_re)\>};
+
+# XXX recursive traversal + templating NYI, one level is enough for a start
+
+for my $file (glob 'template-skel/*') {
+    my $dest = $file;
+    $dest =~ s{^template-skel/}{$destination/};
+    process_file($file, $dest);
+}
+
+sub process_file {
+    my ($source, $dest) = @_;
+    print "Processing '$source' into '$dest'\n";
+    open my $in, '<', $source
+        or die "Cannot open '$source' for reading: $!";
+    open my $out, '>', $dest
+        or die "Cannot open '$dest' for writing: $!";
+    while (<$in>) {
+        s/$subst_re/$vars{$1}/g;
+        print { $out } $_  or die "Cannot write to '$dest': $!";
+    }
+    close $in;
+    close $out or die "Cannot close '$dest': $!";
+}
diff --git a/skel/Configure.pl b/template-skel/Configure.pl
index 90cac74..02aaf31 100644
--- a/skel/Configure.pl
+++ b/template-skel/Configure.pl
@@ -13,6 +13,18 @@ use NQP::Configure qw(sorry slurp cmp_rev gen_nqp read_config
                       system_or_die verify_install);
 
 my $lang = 'Rakudo';
+my $parrot_ver = '<PARROT_VER>';
+my $nqp_ver    = '<NQP_VER>';
+my $rakudo_ver = '<RAKUDO_VER>';
+
+for ($parrot_ver, $nqp_ver, $rakudo_ver) {
+    if (/^<\w+_VER>/) {
+        die "You are running the original version of Configure.pl,\n"
+            . "but you should only run a version which has been processed by\n"
+            . "build/skel-template.pl\n";
+    }
+}
+
 my $lclang = lc $lang;
 my $uclang = uc $lang;
 
@@ -43,7 +55,7 @@ MAIN: {
 
     my $prefix      = $options{'prefix'} || cwd().'/install';
     my $with_parrot = $options{'with-parrot'};
-    $options{'gen-parrot'} ||= 'parrot-4.4.0' if defined $options{'gen-parrot'};
+    $options{'gen-parrot'} ||= "parrot-$parrot_ver" if defined $options{'gen-parrot'};
     my $gen_parrot  = $options{'gen-parrot'};
 
     # Save options in config.status
@@ -59,12 +71,12 @@ MAIN: {
         $options{'gen-nqp'} ||= '';
     }
 
-    $options{'gen-nqp'} ||= 'nqp-2012.05' if defined $options{'gen-nqp'};
+    $options{'gen-nqp'} ||= "nqp-$nqp_ver" if defined $options{'gen-nqp'};
     my $with_nqp    = $options{'with-nqp'};
     my $gen_nqp     = $options{'gen-nqp'};
 
     # determine the version of NQP we want
-    my ($nqp_want) = split(' ', slurp('rakudo-2012.05/tools/build/NQP_REVISION'));
+    my ($nqp_want) = split(' ', slurp("rakudo-$rakudo_ver/tools/build/NQP_REVISION"));
 
     if (defined $gen_nqp) {
         $with_nqp = gen_nqp($nqp_want, %options);