[Python-ideas] Anonymous blocks (again):

[Juancarlo Añez]

Hello,

I've banged my self against the wall, and there simply isn't a pythonic way
to make a context manager iterate over the yielded-to block of code.

I've had to resource to this in Grako[*]:

        def block():
            self.rule()
            self.ast['rules'] = self.last_node
        closure(block)

But what I think would be more pythonic is:

        closure(

        def:
            self.rule()
            self.ast['rules'] = self.last_node
)


Or, better yet (though I know I can't have it):

        with positive_closure():
              self.rule()
              self.ast['rules'] = self.last_node

The thing is that a "closure" needs to call the given block repeatedly,
while remaining in control of the context of each invocation. The examples
given above would signal the closure to be over with an exception.

The convoluted handling of exceptions on context manager's __exit__ make it
impossible (for me) to construct a context manager that can call the
yield-to block several times.

Anyway, the anonymous def syntax, with or without parameters, is a given,
and a solution for many qualms about the Python way of things.

[*] https://bitbucket.org/apalala/grako

-- 
Juancarlo *Añez*
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