Argument checking in Lua?

[Chris Marrin <chris@...>]

Lua 5.1 has some nice argument checking functions, accessible from C, 
like luaL_checknumber() and luaL_optstring(). But these are not 
accessible from Lua, and I have not found anything roughly equivalent. 
It would be easy to write such things, of course, by doing type(), 
checking against nil and throwing errors. But is there any "standard" 
way to do this? I have not been able to find anything...

--
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"As a general rule,don't solve puzzles that open portals to Hell"'