Changes between Version 30 and Version 31 of TypeFunctions
 Timestamp:
 Aug 1, 2006 5:33:51 PM (8 years ago)
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TypeFunctions
v30 v31 22 22 data T a1 .. an :: <kind> 23 23 }}} 24 and introduce a data type whose first {{{n}}} argument are indexes. The {{{<kind>}}}can specify additional parametric parameters. Index variables can have a kind annotation. Indexed newtypes have the same form, except for the keyword.24 and introduce a data type whose first `n` argument are indexes. The `<kind>` can specify additional parametric parameters. Index variables can have a kind annotation. Indexed newtypes have the same form, except for the keyword. 25 25 * Kind signatures of type functions have the form 26 26 {{{ 27 27 type [iso] T a1 .. an :: <kind> 28 28 }}} 29 and introduce an {{{n}}}ary type functions, which may be of higherkind. Again, the type variables can have kind signatures. The modifier {{{iso}}} is optional and requires the type function to be injective.29 and introduce an `n`ary type functions, which may be of higherkind. Again, the type variables can have kind signatures. The modifier `iso` is optional and requires the type function to be injective. (In principle, we could make the `<kind>` optional, with `*` being the default, but we don't do that for uniformity with signatures of indexed types  the form `data T a1 .. an` is already used for empty data types.) 30 30 * Applications of indexed types need to supply all indexes; i.e., partial application to indexes is not admitted. (Arguments beyond the indexes can be partially supplied as usual.) 31 31 * Instances of indexed data types/newtypes and equations of type functions have the same form as vanilla data types/newtypes and type synonyms, respectively, but can have nonvariable type indexes in index positions. Type indexes can include applications of indexed data types and newtypes, but no type functions.