use rec( ("$1") := 2 ) instead of rec( $1 := 2 )

as the latter does not work anymore

From: Alexander Konovalov <alexk@mcs.st-andrews.ac.uk>
Subject: $ in identifiers
Date: 4. Februar 2014 23:37:32 MEZ
To: Mohamed Barakat <mohamed.barakat@rwth-aachen.de>

Dear Mohamed,

sorry for not reporting this before: actually, dollar is no longer allowed in
identifiers. Would it be possible to fix this in GradedRingForHomalg?

...

PackageInfo.g

@@ -27,7 +27,7 @@ Subtitle := "A homalg based package for D-modules",
 ##  See '?Extending: Version Numbers' in GAP help for an explanation
 ##  of valid version numbers. For an automatic package distribution update
 ##  you must provide a new version number even after small changes.
-Version := "2014.01.08",
+Version := "2014.02.04",
 ##  Please adjust also the VERSION file in the package directory when
 ##  changing this.
 

gap/SingularTools.gi

@@ -22,7 +22,7 @@ InstallValue( D_ModulesMacrosForSingular,
 
     _Identifier := "D-Modules",
 
-    $D_Modules_init := "\n\
+    ("$D_Modules_init") := "\n\
 LIB \"bfun.lib\";\n\
 \n\n",