I do not know that I have ever needed 'anonymous blocks', and I have
therefore not followed this discussion in detail, but I appreciate Python's
beauty and want to see it maintained. So I have three comments and
yet-another syntax proposal that I do not remember seeing (but could have
missed).
1. Python's integration of for loops, iterators, and generators are, to me,
a gem of program language design that distinguishes Python from other
languages I have used. Using them to not iterate but to do something else
may be cute, but in a perverted sort of way. I would rather have
'something else' done some other way.
2. General-purpose passable block objects with parameters look a lot like
general-purpose anonymous functions ('full lambdas'). I bet they would be
used a such if at all possible. This seems to me like the wrong direction.
3. The specific use-cases for Python not handled better by current syntax
seem to be rather specialized: resource management around a block. So I
cautiously propose:
with <resource type> <specific resource>: <suite>
with the exact semantics dependent on <resource type>. In particular:
with lock somelock:
codeblock
could abbreviate and mean
somelock.acquire()
try:
codeblock
finally:
somelock.release()
(Guido's example).
with file somefile:
codeblock
might translate to (the bytecode equivalent of)
if isinstance(somefile, basestring?):
somefile = open(somefile,defaults)
codeblock
somefile.close
The compound keywords could be 'underscored' but I presume they could be
parsed as is, much like 'not in'.
Terry J. Reedy
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