[Python-3000] Draft pre-PEP: function annotations (original) (raw)

Phillip J. Eby pje at telecommunity.com
Tue Aug 15 18:05:22 CEST 2006

At 07:04 AM 8/15/2006 -0700, Paul Prescod wrote:

On 8/14/06, Guido van Rossum <<mailto:guido at python.org>guido at python.org> wrote:

Haven't I said that the whole time? I thought that Collin's PEP steered clear from the topic too. At the same time, does this preclude having some kind of "default" type notation in the standard library? The PEP steered TOO far of this topic. If it is total free-for-all then when and if we do come up with a standard syntax (whether in 2006 or 2010) it will conflict with deployed code that used the same syntax to mean something different then the standard. And even if there is never, ever, going to be a standard, it must be possible for tools reading the annotations to know whether the user intended their markup to conform to metadata-syntax 1, where "int" means "32 bit int" or metadata syntax 2 where it means "arbitrary sized int". Similarly, they must know whether the annotater intended to use metadata syntax 1 where "tuple" means "fixed size, heterogenous" or syntax 2 where it means "immutable list".

On the contrary - it is precisely this looseness that the PEP meant to specify, and that I support. The alternative is too restrictive.

Meanwhile, the absence of predefined semantics does not preclude a default type notation existing in the standard library, any more than the absence of a predefined semantics for docstrings or function attributes prevents the stdlib from containing docstring processors or tools that operate on function attributes.

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