[clean-list] Synonym type and Universal type

John van Groningen johnvg at cs.ru.nl
Wed May 30 17:33:57 MEST 2007


TK wrote:
>
>I mean... Has there has been a decision not to include it? ( for being useless, discouraged or alike )

Contexts for algebraic types are not very useful. In that case the
context is required by functions that use a constructor of the type,
but this context is not necessary.

If a context in an algebraic type is used for a variable with an existential
quantifier, the context has to be stored in the constructor (as a dictionary).
This might be useful, but it is more work to implement this.

If a context is specified in type synonym, it probably means that if
the type is used in a function type, the context is automatically added to
the context of the function (if there are still type variables in the
context). This could be confusing.

Kind regards,

John van Groningen


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