updates

[ocean-D] / Ocean-operators

diff --git a/Ocean-operators b/Ocean-operators
index 12b60e20cf06e5fd043fc77f343d14dbc9fdb8da..a2b1ef90788d1d53ef0992c203daf51a927394eb 100644 (file)
--- a/Ocean-operators
+++ b/Ocean-operators
@@ -9,7 +9,7 @@ I might want:
 
  Binary: and then, or else, integer division
  Prefix: int
- Suffix: dereference
+ Suffix: dereference (ref)
 
 
  Do I want  COND ? IFTRUE : IFFALSE
@@ -59,7 +59,7 @@ I might want:
       a @@= b
    does a deep copy
 
-What types do operators act one?
+What types do operators act on?
 
    numbers  + - * / %
    bitsets  & | ~ &~
@@ -77,3 +77,89 @@ What types do operators act one?
       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.
+
+# decided so far:
+
+  +            addition or abs value
+  -            subtraction or negation
+  *            multiply
+  /            div
+  %            remainder
+  ++           catentate
+  ()           group
+  if else      conditional
+  and, or, not  Boolean
+  and then     Boolean
+  or else      Boolean
+  =             assignment
+  :             type
+  < > != == <= >=  comparison
+  [ ]           array access
+  .             field access
+  " ' `         quoting
+  , ;           list
+  {  }          grouping
+
+# expect
+  &            bit and
+  |            bit or
+  &^           bit subtract
+  ^            bit invert (prefix or infix)
+  #             1<< (prefix)
+  << >>         shift
+
+  += -= *= /= %= ++= &= |= &^= ^=
+        What about boolean? and=?
+        if c: a=True // if not c: a=False
+  
+# undecided
+  ?  !  @ $ \ ~
+  -- ** @@ ^^
+
+  Equiv of "a ?: b".  i.e. a if a else b.  Only works if non-Bools can be tested.