[gentoo-dev] [PATCH] metadata: add slots element

[Julian Ospald]

There seems to be some general confusion about specific package SLOTs
and their meaning, since there can be several naming schemes applied
and documentation is either non-existent or is inside the ebuild via
comments.
Because of that it should be part of metadata.xml.

An example use case for media-libs/libpng would be:
<slots>
    <slot name="0">For building against. This is the only slot
        that provides headers and command line tools.</slot>
    <slot name="1.2">For binary compatibility, provides libpng12.so.0.</slot>
    <slot name="1.5">For binary compatibility, provides libpng15.so.15.</slot>
    <subslots>Represent ABI compatibility for libpng.so.</subslots>
</slots>

For packages like x11-libs/wxGTK one could write:
<slots>
    <slot name="*">Major versions.</slot>
</slots>
---
 metadata.dtd | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/metadata.dtd b/metadata.dtd
index ff2649c..4b29f3b 100644
--- a/metadata.dtd
+++ b/metadata.dtd
@@ -5,7 +5,7 @@
 <!ATTLIST catmetadata pkgname CDATA "">
 
 <!-- Metadata for a package -->
-<!ELEMENT pkgmetadata ( (herd|maintainer|natural-name|longdescription|use|upstream)* )>
+<!ELEMENT pkgmetadata ( (herd|maintainer|natural-name|longdescription|slots|use|upstream)* )>
 <!ATTLIST pkgmetadata pkgname CDATA "">
 
   <!-- One tag for each herd this package is assigned to. -->
@@ -20,6 +20,15 @@
   <!-- A long description of the package in freetext-->
   <!ELEMENT longdescription (#PCDATA|pkg|cat)* >
 
+  <!-- A description of the packages SLOTs -->
+  <!ELEMENT slots ((slot)*,subslots?) >
+    <!-- A particular SLOT -->
+    <!ELEMENT slot (#PCDATA)* >
+      <!-- name attribute holds the name of the SLOT, for sub-SLOTS use the subslots element -->
+      <!ATTLIST slot name CDATA #REQUIRED >
+    <!-- The meaning of sub-SLOTs for the whole package -->
+    <!ELEMENT subslots (#PCDATA)* >
+
   <!-- The changelog of the package-->
   <!-- Please note that #PCDATA is mentioned only for the upstream changelog
     element, where the content is a URL. This is due to limitations of the DTD -->
@@ -79,6 +88,7 @@
   language "C" or "en", which is equivalent -->
   <!ATTLIST description lang CDATA "C" >
   <!ATTLIST longdescription lang CDATA "C" >
+  <!ATTLIST slots lang CDATA "C" >
   <!ATTLIST use lang CDATA "C" >
 
 <!-- The restrict attribute, this attribute specifies restrictions on 
-- 
2.6.1