[Types-sig] Non-conservative inferencing considered harmful

skaller skaller@maxtal.com.au
Thu, 23 Dec 1999 08:21:29 +1100


Paul Prescod wrote:
> 
>  * if a variable is consistently assigned a particular type within its
> scope, we inference the type.
>  * if a variable is inconsistently assigned we infer it as "Any"

I'd like to suggest ONE extra case worth considering:

   * particular type OR None

The reason I suggest this, is that it is common enough
for either None or a single type to be used, for example,
often function parameters have a default of None.

It would be a pity to lump this case into the case Any.

-- 
John Skaller, mailto:skaller@maxtal.com.au
10/1 Toxteth Rd Glebe NSW 2037 Australia
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