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int luaL_checkoption (lua_State *L,
int narg,
const char *def,
const char *const lst[]);
Checks whether the function argument narg is a string and
searches for this string in the array lst
(which must be NULL-terminated).
Returns the index in the array where the string was found.
Raises an error if the argument is not a string or
if the string cannot be found.
If def is not NULL ,
the function uses def as a default value when
there is no argument narg or if this argument is nil.
This is a useful function for mapping strings to C enums.
(The usual convention in Lua libraries is
to use strings instead of numbers to select options.) |