# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1491171226 -7200
# Node ID 6487964362bacf51058af435dd17f899da424287
# Parent  ea84f496b3f687c77aaf9667469d17a97e7688d6
Convert operators with lists of operands to pairwise operator invocations.

diff -r ea84f496b3f6 -r 6487964362ba common.py
--- a/common.py	Mon Apr 03 00:12:47 2017 +0200
+++ b/common.py	Mon Apr 03 00:13:46 2017 +0200
@@ -620,12 +620,44 @@
         Process the given operator node 'n' as an operator function invocation.
         """
 
-        op = operator_functions[n.__class__.__name__]
-        invocation = compiler.ast.CallFunc(
+        opname = n.__class__.__name__
+        operands = n.getChildNodes()
+
+        # Convert a unary operation to an invocation.
+
+        op = unary_operator_functions.get(opname)
+
+        if op:
+            invocation = compiler.ast.CallFunc(
+                compiler.ast.Name("$op%s" % op),
+                [operands[0]]
+                )
+
+        # Convert a single operator with a list of operands to a combination of
+        # pairwise operations.
+
+        else:
+            op = operator_functions[opname]
+            invocation = self._process_operator_node(op, operands)
+
+        return self.process_structure_node(invocation)
+
+    def _process_operator_node(self, op, operands):
+
+        """
+        Process the given 'op', being an operator function, together with the
+        supplied 'operands', returning either a single remaining operand or an
+        invocation combining the operands.
+        """
+
+        remaining = operands[1:]
+        if not remaining:
+            return operands[0]
+
+        return compiler.ast.CallFunc(
             compiler.ast.Name("$op%s" % op),
-            list(n.getChildNodes())
+            [operands[0], self._process_operator_node(op, remaining)]
             )
-        return self.process_structure_node(invocation)
 
     def process_print_node(self, n):
 
@@ -1548,6 +1580,15 @@
 
 predefined_constants = "False", "None", "NotImplemented", "True"
 
+unary_operator_functions = {
+
+    # Unary operations.
+
+    "Invert" : "invert",
+    "UnaryAdd" : "pos",
+    "UnarySub" : "neg",
+    }
+
 operator_functions = {
 
     # Fundamental operations.
@@ -1572,12 +1613,6 @@
     "RightShift" : "rshift",
     "Sub" : "sub",
 
-    # Unary operations.
-
-    "Invert" : "invert",
-    "UnaryAdd" : "pos",
-    "UnarySub" : "neg",
-
     # Augmented assignment.
 
     "+=" : "iadd",
@@ -1603,4 +1638,6 @@
     ">" : "gt",
     }
 
+operator_functions.update(unary_operator_functions)
+
 # vim: tabstop=4 expandtab shiftwidth=4