# HG changeset patch
# User Jeff Hammel <jhammel@mozilla.com>
# Date 1307123496 25200
# Node ID e17a3464a0b913e91d8a88e6701cc9aa50f21783
# Parent  15fb1081784f802bf69639d551cf1fc12b783dec
get precedence from a list position vs magic constants

diff -r 15fb1081784f -r e17a3464a0b9 expr.py
--- a/expr.py	Fri Jun 03 10:16:19 2011 -0700
+++ b/expr.py	Fri Jun 03 10:51:36 2011 -0700
@@ -45,33 +45,28 @@
 
 class eq_op_token(object):
     "=="
-    lbp = 20
     def led(self, parser, left):
         return left == parser.expression(self.lbp)
     
 class neq_op_token(object):
     "!="
-    lbp = 20
     def led(self, parser, left):
         return left != parser.expression(self.lbp)
 
 class and_op_token(object):
     "&&"
-    lbp = 11
     def led(self, parser, left):
         right = parser.expression(self.lbp)
         return left and right
     
 class or_op_token(object):
     "||"
-    lbp = 10
     def led(self, parser, left):
         right = parser.expression(self.lbp)
         return left or right
 
 class lparen_token(object):
     "("
-    lbp = 50
     def nud(self, parser):
         expr = parser.expression()
         parser.advance(rparen_token)
@@ -79,11 +74,9 @@
 
 class rparen_token(object):
     ")"
-    lbp = 0
 
 class end_token(object):
-    # lowest left binding power, always ends parsing
-    lbp = 0
+    """always ends parsing"""
 
 ### derived literal tokens
 
@@ -106,6 +99,9 @@
               (eq_op_token, neq_op_token),
               (lparen_token,),
               ]
+for index, rank in enumerate(precedence):
+    for token in rank:
+        token.lbp = index # lbp = lowest left binding power
 
 class ParseError(Exception):
     """errror parsing conditional expression"""