[erlang-questions] Ideas for a new Erlang

Sven-Olof Nystr|m <>
Fri Jun 27 15:33:54 CEST 2008


Ulf Wiger writes:
 > 2008/6/26 Sven-Olof Nystr|m <>:
 > > In my opinion, one great advantage of Erlang over other languages that
 > > use channels is that in Erlang, each process has a "standard" channel
 > > that it normally takes input from. I hope that I was not unclear about
 > > this, but that is a feature of Erlang that I had not intended to change.
 > 
 > But if one of the reasons for wanting channels rather than selective
 > receive on a single mailbox is to make it easier to reason about
 > concurrency, wouldn't keeping an "unscoped" default channel
 > complicate this reasoning?

Maybe. It would certainly be nice to know that if we call a function
in another module it cannot affect any of the channels of the current
process. Thus, there would be a clear distinction between functional
code and code that is involved in process communication.

OTOH, in Erlang there is a one-to-one relationship between processes
and mailboxes which often very natural. There is a similarity between
'self()' in Erlang and referring to the current object in
object-oriented languages (some oo languages actually use the keyword
'self').

I also suspect that it would be inconvenient to add the current
channel as an argument to all functions that perform process
communication. 

 > It's a bit like saying "global variables are bad, so we'll introduce
 > local variables - but global variables are great, so you can have
 > them too."

Only if you think that mailboxes are like global variables :-)


Sven-Olof






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