Changes between Version 6 and Version 7 of Commentary/Compiler/TypeType

Timestamp:

09/14/06 13:31:27 (7 years ago)

Author:

nr

Comment:

--

Commentary/Compiler/TypeType

@@ -19 +19 @@
  * [[GhcFile(compiler/types/Type.lhs)]]: core-view utility functions over {{{Type}}}.
  * [[GhcFile(compiler/typecheck/TcType.lhs)]]: source-view utility functions over {{{Type}}}.
+The "view" functions are ''shallow'', not deep---a view function just looks at the root of the tree representing the type.  This leads to a nice programming idiom in which a case can be guarded by {{Just t' <- coreView t}}, which unfortunately the margin of this Wiki is too small to contain.
 
 The module {{{TypeRep}}} exposes the representation becauese a few other modules ({{{Type}}}, {{{TcType}}}, {{{Unify}}}, etc) work directly on its representation.  However, you should not lightly pattern-match on {{{Type}}}; it is meant to be an abstract type.  Instead, try to use functions defined by {{{Type}}}, {{{TcType}}} etc.