Re^6: RFC: Simulating Ruby's "yield" and "blocks" in Perl (Python)

[LanX]

> I don't really see a win with this style, though, over giving test a parameter, and just using standard function calls (I had a little play with coroutines on the way but that's really overkill for this).

Well I expected decorators to be more flexible, i.e. to redefine test() by putting a wrapper around it and not to built a new decorator @test (!?!)

But I'm not too proficient with Python, and I'm misunderstanding the code.

(well, there must be a reason why I prefer Perl's syntactic flexibility. ;-)

I suppose def _(a) is a way to workaround the limitations of lamda?

Is the name _ special (magic) or is it just a convention?

[MonkOfAnotherSect]

(I've just trimmed the code back in http://perlmonks.com/?node_id=1030806 to use a closure rather than a class -- needed a class back when it was a coroutine... not so much anymore)

Here be Python...

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[LanX]

Thanx, it's clear now.

I was just surprised that you need two decorators!

I thought you could simply do something like

 test(def _(x): print("You are in block %s" % x))

(like  test sub { print("You are in block $_[0]") } in Perl)

Just to get closer to the Ruby feeling and to achieve this

>>> def _(x):
...     print("You are in block %s" % x)
... 
>>> test(_)
In test
You are in block 1
back in test
You are in block 2
test lambda a: print("You are in block %s" % a)

But one needs decorators to manipulate a literal function.

Obviously, there is only this way to do it.

FWIW Python decorators could quite easily be simulated in Perl with attributes.

I will post this soon (if I can't find it already on CPAN) =)

[MonkOfAnotherSect]

If you used a non-keyword such as "send" instead of "yield" you could do Evil and avoid the first decorator. This is left as an exercise. As for the second decorator, sure 'test(lambda a: print("You are in block %s" % a))' will work, but when you require more than one line you're back to using a decorator unless you want to do something truly horrible.

Don't want to do something truly horrible.

-T. "A gentleman is someone who knows how to play the bagpipes but doesn't."