# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1209685639 -7200
# Node ID d06c78713711df12518645c47523f98dde4b3d93
# Parent  3ab797077458571207d5a5ba45d108eca3cacbfc
Fixed the binary operator mechanism.
Expanded the optimisations, incorporating LoadConst into temporary storage
optimisations and adding the optimisation of TestIdentity instructions where one
operand is a constant.

diff -r 3ab797077458 -r d06c78713711 micropython/ast.py
--- a/micropython/ast.py	Mon Apr 28 21:19:42 2008 +0200
+++ b/micropython/ast.py	Fri May 02 01:47:19 2008 +0200
@@ -48,7 +48,7 @@
 
     "A translated module."
 
-    supported_optimisations = ["constant_storage", "known_target", "self_access", "temp_storage"]
+    supported_optimisations = ["constant_storage", "known_target", "self_access", "temp_storage", "constant_test"]
 
     def __init__(self, module, importer, optimisations=None):
 
@@ -541,6 +541,9 @@
     def _should_optimise_constant_storage(self):
         return "constant_storage" in self.optimisations
 
+    def _should_optimise_constant_test(self):
+        return "constant_test" in self.optimisations
+
     def _should_optimise_known_target(self):
         return "known_target" in self.optimisations
 
@@ -568,7 +571,7 @@
         last = self.last_op()
         # NOTE: Should expand to cover LoadAttr and LoadAttrIndex, but this
         # NOTE: would require inspection of the stack operands.
-        return isinstance(last, (LoadName, LoadTemp, LoadAddress))
+        return isinstance(last, (LoadName, LoadTemp, LoadAddress, LoadConst))
 
     # Optimisation methods. See the supported_optimisations class attribute.
 
@@ -607,6 +610,24 @@
         else:
             return 0
 
+    def _optimise_constant_test(self, instruction):
+
+        """
+        Where this operation tests the topmost stack value which happens to be
+        a constant against another stack value, merge the last instruction which
+        loaded the constant into the current 'instruction'.
+        """
+
+        if self._should_optimise_constant_test() and \
+            instruction is TestIdentity and \
+            self._have_constant_input(0):
+
+            last = self.last_op()
+            self.replace_op(TestIdentityAddress(last.attr))
+            return 1
+        else:
+            return 0
+
     def _optimise_known_target(self):
 
         """
@@ -666,12 +687,21 @@
         _t1 = node.left
         _t2 = node.right
         try:
-            _t1.__add__(_t2)
+            _result = _t1.__add__(_t2)
+            if _result is NotImplemented:
+                raise AttributeError
         except AttributeError:
-            _t2.__radd__(_t1)
+            try:
+                _result = _t2.__radd__(_t1)
+                if _result is NotImplemented:
+                    raise AttributeError
+            except AttributeError:
+                raise TypeError
         """
 
+        end_left_label = self.new_label()
         right_label = self.new_label()
+        type_error_label = self.new_label()
         end_label = self.new_label()
 
         # NOTE: Potentially remove the reservation if optimised storage is used.
@@ -696,27 +726,73 @@
 
         self._startCallFunc()
         self.new_op(temp1)
+
+        # Get left method on temp1.
+
         self._generateAttr(node, left_method, (LoadAddress, LoadAttr, LoadAttrIndex))
+        self.dispatch(compiler.ast.Name("AttributeError"))
+        self.new_op(CheckException())
+        self.new_op(JumpIfTrue(end_left_label))
+
+        # Add arguments.
+
         self.new_op(temp1) # Explicit context as first argument.
         self.new_op(temp2)
         self._endCallFunc()
 
-        self.dispatch(compiler.ast.Name("AttributeError"))
-        self.new_op(CheckException())
-        self.new_op(JumpIfFalse(end_label))
+        # Test for NotImplemented.
+        # Don't actually raise an exception.
+
+        self.dispatch(compiler.ast.Name("NotImplemented"))
+        if not self._optimise_constant_test(TestIdentity):
+            self.new_op(TestIdentity())
+        self.new_op(JumpIfTrue(right_label))
+        self.new_op(Jump(end_label))
+
+        # End left method attempt.
+
+        self.set_label(end_left_label)
+        self.new_op(DropFrame()) # From the left method call.
 
         # Right method.
 
         self.set_label(right_label)
         self._startCallFunc()
         self.new_op(temp2)
+
+        # Get right method on temp2.
+
         self._generateAttr(node, right_method, (LoadAddress, LoadAttr, LoadAttrIndex))
+        self.dispatch(compiler.ast.Name("AttributeError"))
+        self.new_op(CheckException())
+        self.new_op(JumpIfTrue(type_error_label))
+
+        # Add arguments.
+
         self.new_op(temp2) # Explicit context as first argument.
         self.new_op(temp1)
         self._endCallFunc()
 
+        # Test for NotImplemented.
+        # Don't actually raise an exception.
+
+        self.dispatch(compiler.ast.Name("NotImplemented"))
+        if not self._optimise_constant_test(TestIdentity):
+            self.new_op(TestIdentity())
+        self.new_op(JumpIfTrue(type_error_label))
+        self.new_op(Jump(end_label))
+
+        # Raise a TypeError.
+
+        self.set_label(type_error_label)
+        self.dispatch(compiler.ast.Name("TypeError"))
+        self.new_op(RaiseException())
+
         self.set_label(end_label)
 
+        # Compilation duties...
+        # NOTE: Potentially remove this when optimised away.
+
         self.discard_temp(2)
 
     def visitAdd(self, node):
diff -r 3ab797077458 -r d06c78713711 micropython/rsvp.py
--- a/micropython/rsvp.py	Mon Apr 28 21:19:42 2008 +0200
+++ b/micropython/rsvp.py	Fri May 02 01:47:19 2008 +0200
@@ -157,4 +157,9 @@
 class Return(Instruction):                      "Return a value from a subprogram."
 class CheckException(Instruction):              "Check the raised exception against another."
 
+# General instructions.
+
+class TestIdentity(Instruction):                "Test whether the two topmost stack values are identical."
+class TestIdentityAddress(Address):             "Test whether the topmost stack value is identical to the given address."
+
 # vim: tabstop=4 expandtab shiftwidth=4