Em Qui, 2009-01-01 às 12:34 -0800, Geoffrey Broadwell escreveu:
> In the below Perl 5 code, I refactored to pull the two halves of the PID
> file handling out of init_server(), but to do so, I had to return a sub
> from pid_file_handler() that acted as a "continuation".  The syntax is a
> bit ugly, though.  Is there a cleaner way to this in Perl 6?


If the STD Perl 6 doesn't support that, you can always declare a
sub-grammar that implements a 

  token routine_def:<coro> {...}

then you have something in the lines of:

  coro pid_file_handler {
      ... # first half
      yeld $something;
      ... # second half

It's even easy to implement how it should work. Basically, yeld throws a
resumable control exception, the implicit "CONTROL" block of the routine
will then contain the code to handle that exception by aliasing the coro
in that state in the caller lexical scope, overriding the current
definition. And once the routine is called again, and returns or leaves,
you simply re-binds to the original routine. 

The above solution assumes a coro state is only available in the same
lexical scope as the first call, which may be a good idea to avoid

But maybe we even convince larry to push that into STD... since it's
such a nice feature...


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