Re: luaL_checkboolean() equivalent?

[Peter Odding <peter@...>]

> I'm new to the Lua C interface and wonder if comeone can suggest
> the best Lua idiom to receive a boolean parameter into a C function?
> 
> I was hoping for something like:
> 
> int self_destruct( lua_state *L )
> {
>    bool are_you_sure = luaL_checkboolean( L, 1 );
> 
> but luaL_checkboolean doesn't exist. Of course, it couldn't fail with
> a type error, because nil and false are false, while true and
> everything else are true, but do I really have to check the type of
> the parameter and check for nil and false explicitly, with some garply
> like:
> 
>   bool are_you_sure = ! ( lua_isnil( L, 1 ) || (lua_isboolean( L, 1 )
> && ! lua_toboolean( L, 1 ) );
> 
> or is there a cleaner way?

I'd say just go with the flow of Lua (that is to say everything except
nil and false is true) and use the following:

  bool are_you_sure = lua_toboolean(L, 1);

Insisting on a value of type boolean doesn't add any value IMHO; Lua
generally doesn't do strict type checking so why bother with it here?

 - Peter