Re: Icon Co-Expressions in Ada

[Chris Morgan <mihalis@ix.netcom.com>]

Mats Weber <Mats.Weber@elca-matrix.ch> writes:

> This sounds like coroutines in other languages. The closest Ada has to
> offer is tasks, but as Ada tasks can be called concurrently, you will
> have a significant overhead over a simple coroutine mechanism.

A standard technique in JSD is to map many theoretical processes or
state machines in the design into one Ada task (often referred to as a
group). In the toolset I use to work on this meant that the Ada for a
particular process became a chunk of flat code with gotos and
labels. In the design we worked as if the process ran concurrently
with the other ones in the group and we could use loops and so
on. This structure was "read-inverted" by the toolset so each process
became just a procedure with an extra parameter of the state. The
loops were simulated of course. I thought this made sense as we were
taught to regard using a whole task as expensive. It often occurred to
me how grotesque it was stepping through spaghetti machine generated
code with gotos and labels, but that's the price for some of these
high-concept design techniques with "automatic" code generation.

Chris
-- 
Chris Morgan <mihalis at ix.netcom.com>		http://www.mihalis.net