[Python-Dev] A Hygienic Macro System in Python?

[Greg Ewing]

Paul Prescod <paul@prescod.net>:

> Mixed feelings on that...not a big fan of the Ruby indiom:
> 
> 5.dotimes():
>    print "Hello";

My proposal has the (possibly minor) advantage over the Ruby syntax
that it doesn't have the (), so that it more closely resembles the
syntax of built-in control structures, and doesn't look so much like
you're making a call with one less parameter than you really
are. (Unfortunately, in the process, it manages to obscure that you're
making a call at all. :-[)

If you don't like the look of the dot-notation in that position, the
lock example could be done using a procedure instead of a method of
the lock object:

  withlock mylock:
    do_something()

  def withlock(lock, body):
    lock.acquire()
    try:
      body()
    finally:
      lock.release()

> I sort of like the fact that Python figures out what control flow
> features people need (e.g. foreach and simple generators) and just
> implements.

Yes, but the feature we're talking about is designed for those cases
where you badly need a control structure that Guido hasn't thought of
yet.

Greg Ewing, Computer Science Dept, +--------------------------------------+
University of Canterbury,	   | A citizen of NewZealandCorp, a	  |
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