updates

[ocean-D] / Ocean-operators

diff --git a/Ocean-operators b/Ocean-operators
index 12b60e20cf06e5fd043fc77f343d14dbc9fdb8da..d70058b19df36c9832cc463ab6f9b2cd4bf8aeeb 100644 (file)
--- a/Ocean-operators
+++ b/Ocean-operators
@@ -77,3 +77,49 @@ What types do operators act one?
       convert error to type     !error
       test if value is error    ?value
       extract error code        value!
       convert error to type     !error
       test if value is error    ?value
       extract error code        value!

+
+
+PROBLEM??
+
+  a if c else b
+could have a natural precedence:
+
+  A if C else B if q else a if c else b
+would be
+  A if C else (B if q else (a if c else b))
+Hmm..  not what I imagined.  But what I imaging suggested that left-association what
+ a op b op c -> (a op b) op c
+requires that we reduce even when we could shift, ... maybe .... I should leave this
+until I do precedence.
+
+--------------------------
+
+Thinking about bit operators.
+
+#foo  is 2^foo
+So #12-#4 is
+    1000000000000 -
+            10000
+=    111111110000
+which is bits 4 thru 11
+
+I'm wondering if it is useful to have a field-select operator,
+which could be '#' as infix (rather than prefix) so
+
+  var # field
+
+would be an lval which can only modify the selected bits
+
+  var # #12-#4 = #6-#4
+would clear bits 6-11.  Doesn't actually read very well, does it?
+Probably better to use field syntax, with a way to declare fields for an int.
+This would be a record.
+
+Still.
+   var &~= #4
+   var |= #4
+to clear and set bits looks OK.
+But ... what syntax do I want for test-and-set?  More genericly cmpxchg.
+An operator that modifies a variable is something I wanted to avoid.
+  var ? oldval = newval
+could 'use false' if it fails.