Comments on: meta-methods: python vs tinypy http://www.philhassey.com/blog/2008/05/27/meta-methods-python-vs-tinypy/ games, tech, web, stuff, biz, and bilge Wed, 03 Dec 2008 07:13:49 +0000 http://wordpress.org/?v=2.5.1 By: Chris Swetenham http://www.philhassey.com/blog/2008/05/27/meta-methods-python-vs-tinypy/#comment-4428 Chris Swetenham Thu, 12 Jun 2008 09:41:21 +0000 http://www.philhassey.com/blog/2008/05/27/meta-methods-python-vs-tinypy/#comment-4428 Although it is very elegant, a.x == a["x"] is actually one of the design decisions I like least in Lua, because it means that you can't have methods on an arbitrary indexable collection. Metamethods also have a problem in Lua; they must be directly in the metatable of an object (__add for instance won't be looked up in the metatable.__index of the metatable, etc, but only in the metatable itself). You can either give instances a metatable whose __index is their class, or put the metamethods in the class and have the class as metatable, but either way there's no simple solution to inheriting metamethods in Lua. Although it is very elegant, a.x == a["x"] is actually one of the design decisions I like least in Lua, because it means that you can’t have methods on an arbitrary indexable collection.

Metamethods also have a problem in Lua; they must be directly in the metatable of an object (__add for instance won’t be looked up in the metatable.__index of the metatable, etc, but only in the metatable itself). You can either give instances a metatable whose __index is their class, or put the metamethods in the class and have the class as metatable, but either way there’s no simple solution to inheriting metamethods in Lua.

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