Re: "Redirecting" stdout, stderr

["Andy Stark" <astark@...>]

David Given writes:
>
>I have an embedded system with no stdio (not even FILE*),
>
>so had to hack all that stuff out of the Lua core. It was non-trivial.

I have always thought it would be a major help to embedders if the Lua
source NEVER used the I/O routines from the C standard library directly.
They should all be wrapped inside functions defined in a single source
file. The functions would be called something like "lua_printf", etc, and
would simply pass their parameters onto the standard library routines. All
other parts of the Lua source should then call lua_printf rather than just
printf. Using this system, the crucial I/O routines would all be collected
in one obvious place and would only have to be modified once by anyone
having trouble with them.

This would be a benefit in several cases:-

- Places where no console output is available (eg, microwave oven or pure
GUI environment like classic MacOS).

- PalmOS and possibly others recommended that you use equivalent system
calls instead of C standard library routines in order to save memory.

- Plug-ins (eg, Photoshop) might need to report errors and messages by
some pre-arranged mechanism rather than on the console.

And there must be many other similar cases, all easily handled if the I/O
routine calls are wrapped as described above. Lua's main unique "killer"
feature is its superb embeddability - this feature should be developed as
far as possible.

Ideally, the Lua core (not including the file library, etc) should not use
any I/O routines from the C standard lib, but should pass message strings
upwards to be handled by the embedding program. This would probably be a
major task, however, and might require the Lua team to write their own
version of sprintf!

Just a few observations from my experiences. No need to get angry if you
disagree with me!

&.


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