On 2010年6月22日 07:31:12 +0300, David Manura <dm.lua@math2.org> wrote:
To followup [1], can someone remind me what is the rationale for Lua 5.1 tables not storing an explicit table length, which thereby prevents trailing nils from being regularly counted in the table length? I'm not suggesting storing length in a regular table key, like the Lua 5.0 "n" field which affects things like pairs iteration, but rather storing it in some hidden location accessible only via the # operator.
The best summary was here (replace "definition" with "implementation"): http://lua-users.org/lists/lua-l/2010-06/msg00100.html Main issue is that automatically maintaining the hidden "n" has a runtime cost that is not acceptable for all users.