[Haskell-cafe] Local types

[Kosyrev Serge]

Languages should express our intent, and giving type and instance
declarations the ability to be localised will enable them to serve as
better vehicles of expression.

That said,

Imants Cekusins <imantc at gmail.com> writes:
>> local types and instances
>
> is this not an attempt to move module functionality inside function?

Same counter-argument can be applied to local functions.

> would this not encourage larger functions? are larger functions a good thing?

Same as above.

> could this not be better addressed by allowing explicit export /
> hiding of instances in a module?

If I interpret the intent correctly, this is specifically about finer
granularity than module level.

> does not type declaration inside function come at a performance cost?

Generally speaking, and whether this suggested cost is real,
Haskell programmers are more or less used to pay the cost of abstraction.

-- 
с уважениeм / respectfully,
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