Changeset 12002 for src/Pugs/Val

Timestamp:

08/08/06 17:55:39 (2 years ago)

Author:

audreyt

Message:

* Finally, an extremely sane treatment for item/list contexts.

both only occur in ByVal? (i.e. when the return continuation is
expecting something not "is rw").

The compiler inserts a runtime dispatch of .item or .list on the
term (usually a container).

A user-defined object can elect to return its content
(like Scalar.item, Scalar.list and Array.list) or not
(like Array.item, Hash.item and Int.list).

The choice in Hs level is controlled in asList and asItem
method; the P6 level equivalence would be ".item" and ".list"
unless later overruled. :-)

* Bridged this treatment to oldland VV as well.

Files:

• src/Pugs/Val/Str.hs (modified) (1 diff)

src/Pugs/Val/Str.hs

@@ -23 +23 @@
     asStr    :: a -> m PureStr
     asStr x = return (cast "<opaque>") -- XXX wrong
+    -- "$item = VAL"
+    asItem   :: a -> Maybe (m Val)
+    asItem _ = Nothing -- default = do nothing (for Scalar this would return its content)
+    -- "@list = VAL"
     asList   :: a -> Maybe (m PureList)
-    asList _ = Nothing -- default = do not flatten
+    asList _ = Nothing -- default = do nothing (for Scalar this would return its content wrapped in a 1-seq)
     asNative :: a -> m ValNative
     asNative = fmap (NBuf . cast) . asStr