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- Subject: Re: __declared
- From: Jose Torre-Bueno <jtorrebueno@...>
- Date: Wed, 30 Oct 2013 16:47:22 -0700
On Oct 30, 2013, at 4:17 PM, Jose Torre-Bueno <jtorrebueno@cox.net> wrote:
>
> Poking about I discovered that the metatable for _G (or _ENV) has a table called __declared whose keys are the names of user defined objects and value is always true. This seems a useful thing for testing whether a function has been defined or a table exists.
Even stranger sometimes I can get the metatable for _G and sometimes not as shown in this interpreter record:
Lua 5.2.0 Copyright (C) 1994-2011 Lua.org, PUC-Rio
> =getmetatable(_G)
nil
> require'utilities'
> =getmetatable(_G)
nil
> require'evolve2'
> = getmetatable(_G)
table: 0x100130730
>
utilities is 658 lines of Lua and evolve2 is 1533 lines, neither makes any C calls, also just loading them w/o running any functions is enough to make the metatable visible.
Jose de la Torre-Bueno, Ph.D.
Empowered Energy Solutions Inc.
Intellectual Property & Technology Management
T (619) 977-0553
F (760) 295-7119
jtorrebueno@cox.net
