Feature Proposal: Extend VarVAR to referencing variables defined in a topic.

Motivation

This conversation from TWiki irc sums up the motivation:

Lynnwood - Doesn't it seem strange that there's not an easy way to generate the list of members of TWikiAdminGroup or other groups?
There is even the local variable GROUP defined within the TWikiAdminGroup topic, but there's no easy way to call locally defined variable...
Maybe we should have a %GROUPMEMBERS{TWikiAdminGroup}% tag.    [05:21]
Lynnwood   Here's an idea: how about extending the syntax of INCLUDE to expand variables within the referenced topic.
So %INCLUDE{"TWikiAdminGroup" GROUP}% would render the GROUP variable as defined in that topic.    [06:10]
PeterThoeny - possibly a different syntax? There is already a %VAR{"NAME" web="Web"}%
Perhaps: %VAR{ "NAME" web="Web" topic="OtherTopic" }%
Lavr - Good morning. I never understood why VAR{"NAME" web="Web"} did not also allow VAR{"NAME" topic="topic" web="Web"}. You really could use this very often.    [07:15]
PeterThoeny   good morning. looks like a sensible enhancement, yes

Description and Documentation

Proposed: Simply add a "topic" attribute to VarVAR. For example: %VAR{ "NAME" web="Web" topic="OtherTopic" }% would expand the varible NAME from Web.OtherTopic.

Examples

Impact and Available Solutions

Implementation

-- Contributors: LynnwoodBrown

Discussion

-- LynnwoodBrown - 16 Nov 2006

This looks like BringTopicVarsIntoCore, and that was just waiting for a good generic, clean, unambigous syntax. Are we there?

-- ArthurClemens - 16 Nov 2006

I noted BringTopicVarsIntoCore as a "related topic" and now Crawford has posted CanonicalTWikiVariables. I'm sure there are other opinions floating out there but personally, i think extending the VarVAR syntax is pretty simple and clean.

-- LynnwoodBrown - 16 Nov 2006