[luatex] Why LuaTeX forces extension on reading and writing files?

[Herbert Voss]

Am 19.01.2016 um 13:21 schrieb Igor Liferenko:

> LuaTeX requires extension in file name to work correctly. Consider these tests:
>
> Test for reading (does not work without extension):
>
>      $ echo a > in
>
>      \newread\infile
>      \openin\infile=in

\openin\infile={in}

works

Herbert