I'm starting to get quite indisciplined about where I introduce global
bindings. Seems reasonable since any modules in Teliva will come from
within the framework.
Teliva isn't yet smart enough to know the caller of an indirect function
where the function being called goes through a local variable.
I'd expected fixing this to be a long death march. However, there's a
shockingly easy fix: just make every indirect call go through an
additional direct function call.
My policy for zet.tlv was that function 'main' could open any file. This
stopped working since I introduced spawn_main. But with this commit it's
working again.
I can also drop all my special-casing of 'main' since it's now a regular
Lua call.
We still can't rely on the caller of an indirect call. That affects
start_reading and start_writing, which really need to be part of the
framework.
File operations now always return a channel (or nil on error or
permission denied).
When start_reading() from a filename, you can repeatedly :recv() from
the channel it returns.
When :recv() returns nil, you're at the end of the file. Stop.
When you start_writing() to a filename, you can repeatedly :send() to
the channel it returns.
When you're done writing, :close() the channel. Writes to the file won't
be externally visible until you do.
To make this work I'm now always starting up the scheduler, so I need to
fix sieve.tlv.
Transparently running the scheduler is an abstraction, and whenever I
create an abstraction I always worry about how it might fail. There's
a hopefully-clear error when you read past end of a file.
Kartik K. Agaram