Newtype wrappers

Johan Tibell johan.tibell at
Mon Jan 14 23:55:31 CET 2013

On Mon, Jan 14, 2013 at 2:33 PM, Roman Cheplyaka <roma at> wrote:
> * Johan Tibell <johan.tibell at> [2013-01-14 14:29:57-0800]
>> Let me rephrase: how will Simon's proposed "data constructors are in
>> scope" mechanism work? For example, will
>>     let xs :: Map = ...
>>     in map MyNewtype xs
>> behave differently if the constructors of Map are in scope or not?
> Coercion is never implicit. In Simon's original proposal, for example,
> you need to define coercion functions using a special syntax.
> So this code will always work in the same, traditional way.

I'm completely lost. What is Simon's proposal?

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