diff --git a/pisi-spec.rng b/pisi-spec.rng
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+++ b/pisi-spec.rng
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+<?xml version="1.0" encoding="UTF-8"?>
+<!-- RELAX NG schema file for PISI pspec.xml files -->
+<!-- http://www.pardus.org.tr/projeler/pisi/ -->
+
+<grammar xmlns="http://relaxng.org/ns/structure/1.0">
+
+  <!-- Start Document -->
+  <start>
+    <choice>
+      <ref name="PISI"/>
+    </choice>
+  </start>
+
+  <!-- PISI Section -->
+  <define name="PISI">
+    <element name="PISI">
+      <ref name="Source"/>
+      <oneOrMore>
+        <ref name="Package"/>
+      </oneOrMore>
+      <ref name="History"/>
+    </element>
+  </define>
+
+  <!-- Source Section -->
+  <define name="Source">
+    <element name="Source">
+      <ref name="Name"/>
+      <ref name="Homepage"/>
+      <ref name="Packager"/>
+      <oneOrMore>
+	<ref name="License"/>
+      </oneOrMore>
+      <optional>
+      	<ref name="Icon"/>
+      </optional>
+      <oneOrMore>
+	<ref name="IsA"/>
+      </oneOrMore>
+      <optional>
+	<ref name="PartOf"/>
+      </optional>
+      <oneOrMore>
+	<ref name="Summary"/>
+      </oneOrMore>
+      <zeroOrMore>
+	<!-- FIXME: should be oneOrMore -->
+	<ref name="Description"/>
+      </zeroOrMore>
+      <ref name="Archive"/>
+      <optional>
+	<ref name="BuildDependencies"/>
+      </optional>
+      <optional>
+	<ref name="Patches"/>
+      </optional>
+    </element>
+  </define>
+
+  <!-- Package Section -->
+  <define name="Package">
+    <element name="Package">
+      <ref name="Name"/>
+      <optional>
+	<ref name="License"/>
+      </optional>
+      <optional>
+	<ref name="IsA"/>
+      </optional>
+      <optional>
+	<ref name="PartOf"/>
+      </optional>
+      <zeroOrMore>
+	<ref name="Summary"/>
+      </zeroOrMore>
+      <zeroOrMore>
+	<ref name="Description"/>
+      </zeroOrMore>
+      <optional>
+      <ref name="RuntimeDependencies"/>
+      </optional>
+      <optional>
+	<ref name="Conflicts"/>
+      </optional>
+      <ref name="Files"/>
+      <optional>
+	<ref name="AdditionalFiles"/>
+      </optional>
+      <optional>
+	<ref name="Provides"/>
+      </optional>
+    </element>
+  </define>
+
+  <!-- History Section -->
+  <define name="History">
+    <element name="History">
+      <oneOrMore>
+        <ref name="Update"/>
+      </oneOrMore>
+    </element>
+  </define>
+
+
+  <!-- Name -->
+  <define name="Name">
+    <element name="Name">
+      <text/>
+    </element>
+  </define>
+
+  <!-- Homepage -->
+  <define name="Homepage">
+    <element name="Homepage">
+      <text/>
+    </element>
+  </define>
+
+  <!-- Icon -->
+  <define name="Icon">
+    <element name="Icon">
+      <text/>
+    </element>
+  </define>
+
+  <!-- Packager -->
+  <define name="Packager">
+    <element name="Packager">
+      <ref name="Name"/>
+      <ref name="Email"/>
+    </element>
+  </define>
+
+  <!-- Email -->
+  <define name="Email">
+    <element name="Email">
+      <text/>
+    </element>
+  </define>
+
+  <!-- License -->
+  <define name="License">
+    <element name="License">
+      <text/>
+    </element>
+  </define>
+
+  <!-- IsA -->
+  <define name="IsA">
+    <element name="IsA">
+      <!-- TODO: Define available choices? -->
+      <text/>
+    </element>
+  </define>
+
+  <!-- PartOf -->
+  <define name="PartOf">
+    <element name="PartOf">
+      <text/>
+    </element>
+  </define>
+
+  <!-- Summary -->
+  <define name="Summary">
+    <element name="Summary">
+      <ref name="attlist.Summary"/>
+      <text/>
+    </element>
+  </define>
+  <!-- attlist.Summary -->
+  <define name="attlist.Summary" combine="interleave">
+    <optional>
+      <attribute name="xml:lang"/>
+    </optional>
+  </define>
+
+  <!-- Description -->
+  <define name="Description">
+    <element name="Description">
+      <ref name="attlist.Description"/>
+      <text/>
+    </element>
+  </define>
+  <!-- attlist.Description -->
+  <define name="attlist.Description" combine="interleave">
+    <optional>
+      <attribute name="xml:lang"/>
+    </optional>
+  </define>
+
+  <!-- Archive -->
+  <define name="Archive">
+    <element name="Archive">
+      <ref name="attlist.Archive"/>
+      <text/>
+    </element>
+  </define>
+  <!-- attlist.Archive -->
+  <define name="attlist.Archive" combine="interleave">
+    <group>
+      <attribute name="sha1sum"/>
+      <!-- NOTE: we can limit possible types here to the ones that pisi know -->
+      <attribute name="type"/>
+    </group>
+  </define>
+
+  <!-- BuildDependencies -->
+  <define name="BuildDependencies">
+    <element name="BuildDependencies">
+      <oneOrMore>
+        <ref name="Dependency"/>
+      </oneOrMore>
+    </element>
+  </define>
+
+  <!-- Dependency -->
+  <define name="Dependency">
+    <element name="Dependency">
+      <ref name="attlist.VersionReleaseToFrom"/>
+      <text/>
+    </element>
+  </define>
+
+  <!-- attlist.VersionReleaseToFrom -->
+  <define name="attlist.VersionReleaseToFrom">
+    <group>
+      <optional>
+	<attribute name="versionFrom"/>
+      </optional>
+      <optional>
+	<attribute name="versionTo"/>
+      </optional>
+      <optional>
+	<attribute name="version"/>
+      </optional>
+      <optional>
+	<attribute name="releaseFrom"/>
+      </optional>
+      <optional>
+	<attribute name="releaseTo"/>
+      </optional>
+      <optional>
+	<attribute name="release"/>
+      </optional>
+    </group>
+  </define>
+
+  <!-- Patches -->
+  <define name="Patches">
+    <element name="Patches">
+      <oneOrMore>
+        <ref name="Patch"/>
+      </oneOrMore>
+    </element>
+  </define>
+
+  <!-- Patch -->
+  <define name="Patch">
+    <element name="Patch">
+      <ref name="attlist.Patch"/>
+      <text/>
+    </element>
+  </define>
+  <!-- attlist.Patch -->
+  <define name="attlist.Patch" combine="interleave">
+    <group>
+      <optional>
+	<attribute name="compressionType"/>
+      </optional>
+      <optional>
+	<attribute name="level"/>
+      </optional>
+      <optional>
+	<attribute name="target"/>
+      </optional>
+    </group>
+  </define>
+
+  <!-- Provides -->
+  <define name="Provides">
+    <element name="Provides">
+      <oneOrMore>
+        <ref name="COMAR"/>
+      </oneOrMore>
+    </element>
+  </define>
+
+  <!-- COMAR -->
+  <define name="COMAR">
+    <element name="COMAR">
+      <ref name="attlist.COMAR"/>
+      <text/>
+    </element>
+  </define>
+  <!-- attlist.COMAR -->
+  <define name="attlist.COMAR">
+    <optional>
+      <attribute name="script"/>
+    </optional>
+  </define>
+
+  <!-- Conflicts -->
+  <define name="Conflicts">
+    <element name="Conflicts">
+      <oneOrMore>
+	<ref name="Conflicts.Package"/>
+      </oneOrMore>
+    </element>
+  </define>
+
+  <define name="Conflicts.Package">
+    <element name="Package">
+      <ref name="attlist.VersionReleaseToFrom"/>
+      <text />
+    </element>
+  </define>
+
+  <!-- AdditionalFiles -->
+  <define name="AdditionalFiles">
+    <element name="AdditionalFiles">
+      <oneOrMore>
+        <ref name="AdditionalFile"/>
+      </oneOrMore>
+    </element>
+  </define>
+
+  <!-- AdditionalFile -->
+  <define name="AdditionalFile">
+    <element name="AdditionalFile">
+      <ref name="attlist.AdditionalFile"/>
+      <text/>
+    </element>
+  </define>
+  <!-- attlist.AdditionalFile -->
+  <define name="attlist.AdditionalFile">
+    <attribute name="target"/>
+    <optional>
+      <attribute name="permission"/>
+    </optional>
+    <optional>
+      <attribute name="owner"/>
+    </optional>
+  </define>
+
+  <!-- RuntimeDependencies -->
+  <define name="RuntimeDependencies">
+    <element name="RuntimeDependencies">
+      <oneOrMore>
+        <ref name="Dependency"/>
+      </oneOrMore>
+    </element>
+  </define>
+
+  <!-- Files -->
+  <define name="Files">
+    <element name="Files">
+      <oneOrMore>
+        <ref name="Path"/>
+      </oneOrMore>
+    </element>
+  </define>
+
+  <!-- Path -->
+  <define name="Path">
+    <element name="Path">
+      <ref name="attlist.Path"/>
+      <text/>
+    </element>
+  </define>
+  <!-- attlist.Path -->
+  <define name="attlist.Path" combine="interleave">
+    <group>
+      <attribute name="fileType">
+	<choice>
+	  <value>executable</value>
+	  <value>library</value>
+	  <value>data</value>
+	  <value>config</value>
+	  <value>doc</value>
+	  <value>man</value>
+	  <value>info</value>
+	  <value>localedata</value>
+	  <value>header</value>
+	</choice>
+      </attribute>
+      <optional>
+	<attribute name="permanent">
+	  <choice>
+	    <value>false</value>
+	    <value>true</value>
+	  </choice>
+	</attribute>
+      </optional>
+    </group>
+  </define>
+
+
+
+  <!-- Update -->
+  <define name="Update">
+    <element name="Update">
+      <ref name="attlist.Update"/>
+      <ref name="Date"/>
+      <ref name="Version"/>
+      <ref name="Comment"/>
+      <ref name="Name"/>
+      <ref name="Email"/>
+    </element>
+  </define>
+  
+  <!-- attlist.Update -->
+  <define name="attlist.Update" combine="interleave">
+    <attribute name="release"/>
+    <optional>
+      <!-- FIXME: valid types must be used instead of CDATA (a.k.a choice)-->
+      <attribute name="type"/>
+    </optional>
+  </define>
+
+  <!-- Date -->
+  <define name="Date">
+    <!-- FIXME: Take a look at xmlschema data types at http://www.w3.org/TR/xmlschema-2/#dateTime -->
+    <element name="Date">
+      <text/>
+    </element>
+  </define>
+
+  <!-- Version -->
+  <define name="Version">
+    <element name="Version">
+      <text/>
+    </element>
+  </define>
+
+  <!-- Comment -->
+  <define name="Comment">
+    <element name="Comment">
+      <text/>
+    </element>
+  </define>
+
+</grammar>