Changes between Version 8 and Version 9 of Language

Timestamp:

06/24/09 09:58:50 (4 years ago)

Author:

benl (IP: 150.203.160.45)

Comment:

--

Language

@@ -203 +203 @@
 
 The return kind of abstract class constraints must be {{{+}}}. We don't yet support default instances in type class declarations #90.
+
+[[br]]
+
+== !InstanceDecl ==
+
+{{{
+InstanceDecl
+    ::=  instance  Con  SimpleType+  where  {  Binding;+  }
+}}}
+
+[[br]]
+
+== !ProjectionDecl ==
+
+{{{
+ProjectionDecl
+    ::=  project  Con  SimpleType*  where  {  (TypeSig|Binding)+  }    -- projection dictionary
+     |   project  Con  SimpleType*  with   {  Var+  }                  -- projection punning
+}}}
+
+The first form defines some projection functions associated with a given type. Presently, all projections associated with a type must be declared in the same projection declaration and in the same source module, but there is a plan to relax this #7.
+
+If two projection dictionaries are defined for types that overlap, eg List Int and List a, then the result is currently undefined. There is a ticket to fix this #40.
+
+The projection punning syntax imports bindings at top level into the projection name space. For example:
+
+{{{
+project Set a with { insert; delete; size }
+}}}
+
+Is equivalent to
+{{{
+project Set a where { insert = insert; delete = delete; size = size }
+}}}
+
+This is useful when implementations of {{{insert}}}, {{{delete}}} and {{{size}}} are in the current module, but only the type {{{Set}}} is exported. All projections associated with a certain type are exported when the type is.
+
+
+== !TypeSig ==
+
+{{{
+TypeSig
+    ::=  Var  ::  Type
+}}}
+
+