I'm not married to the colon. Does anyone else see any issue with dropping it? On 18 February 2017 at 00:27, David Mertz <mertz@gnosis.cx> wrote:
On Fri, Feb 17, 2017 at 2:35 PM, Joseph Hackman <josephhackman@gmail.com> wrote:
I think we should use the colon to make the delayed word (or whatever word is selected), unambiguously used in this way (and to prevent any existing code from breaking).
On 17 February 2017 at 17:09, David Mertz <mertz@gnosis.cx> wrote:
That was a problem with the colon that occurred to me. I think it can't be tokenized in function annotations.
I don't see any reason for delayed execution and function annotations to mix. i.e. def foo(delayed: bar): pass would define a function that takes one argument, named delayed, of type bar.
I still think the colon is ugly and inconsistent with other Python uses. I know you are trying for analogy with lambda (which is related, yes). But the analogies with yield, yield from, async, and await feel much stronger to me. Also, 'lambda' *requires* the colon since it might take arguments and that is necessary to tell when they end.[*] 'delayed' like those other words I mention has no such need.
That said, I think you are right that it makes no sense to declare a function signature with 'delayed' (or 'lazy', 'deferred', whatever word). Calling it definitely! This feels important:
x = foo(delayed very_complex_computation())
But in the definition signature it feels nonsensical, I agree. However, that still doesn't answer other uses of the colon:
{delayed: 17} # No idea if this is a set of one delayed object or a dictionary lambda delayed: delayed: 17 # Just don't know where to start with this
All these problems simply go away if we drop the colon.
[*] i.e. what would this colon-free lambda mean: 'lambda a, b, c'? A function of no arguments return a tuple? a function of three arguments?
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