Unpicking require

[Gavin Wraith <gavin@...>]

I am trying to understand the source code for 'require' in loadlib.c and 
would be grateful for some help. The reason is that 'require' does not 
behave for RISC OS in quite the way I want. The file-naming conventions 
of RISC OS are different from both Unix and Windows. This is partly 
taken care of by the flexibility of LUA_PATH_SEP in luaconf.h, but not 
entirely. There is no notion of filename-extension in RISC OS, and a 
file's type is instead a built-in attribute determined by six bits 
within the file itself. This means that for translating between RISC OS 
and Unix it is convenient to swap the characters '.' and '/'; the dot is 
the directory-separator in RISC OS. In loadlib.c an explicit "." appears 
in the functions 'findfile', 'll_searchpath' and 'loadfunc'; also an 
explicit '.' appears in function 'searcher_Croot'. But I am not sure 
which sense the dot has in these cases. Is it 'current directory' or 
'filename-extension-introduction'?

At present 'require "foo"' works as it should for RISC OS, but 'require 
"foo.bar"' does not. I would like all dots in the argument string to 
'require' to be passed through to the file-loading functions unchanged. 
I wondered whether the explicit mention of "." in the loadlib.c sources 
was the cause of my problem.