Re: [PROPOSAL] more luaL_check* in lauxlib.h (for Lua 5.2)

[Tony Finch <dot@...>]

François Perrad <francois.perrad@gadz.org> wrote:

> I propose the addition of the following macros in lauxlib.h :
>   #define luaL_checkboolean(L,n)    (luaL_checktype(L, (n), LUA_TBOOLEAN))

Use lua_toboolean. It is more idiomatic than requiring that a value is
exactly true or false.

>   #define luaL_checknil(L,n)    (luaL_checktype(L, (n), LUA_TNIL))

Requiring a function argument to be nil doesn't make sense.

>   #define luaL_checktable(L,n)    (luaL_checktype(L, (n), LUA_TTABLE))

Prevents callers from passing an object with a suitable metatable.

In general the luaL_check* functions deal with transferring data from Lua
to C, and raise an error if this is not possible. If a value remains in
Lua, such as a function or a table, it's easier to just use it as if it
has the type you expect, and allow the lower-level checks to do their job.

Tony.
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