A host program can execute Lua chunks written in a file or in a string,
using the following functions:
int lua_dofile (char *filename);
int lua_dostring (char *string);
Both functions return an error code:
0, in case of success; non zero, in case of errors.
More specifically, lua_dofile returns 2 if for any reason
it could not open the file.
The function lua_dofile, if called with argument NULL (0),
executes the stdin stream.
Function lua_dofile is also able to execute pre-compiled chunks.
It automatically detects whether the file is text or binary,
and loads it accordingly (see program luac).