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diff --git a/src/examples/simpleBool.py b/src/examples/simpleBool.py
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+++ b/src/examples/simpleBool.py
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+#
+# simpleBool.py
+#
+# Example of defining a boolean logic parser using
+# the operatorGrammar helper method in pyparsing.
+#
+# In this example, parse actions associated with each
+# operator expression will "compile" the expression
+# into BoolOperand subclass objects, which can then
+# later be evaluated for their boolean value.
+#
+# Copyright 2006, by Paul McGuire
+#
+
+from pyparsing import *
+
+class BoolOperand(object):
+    def __init__(self,t):
+        self.args = t[0][0::2]
+    def __str__(self):
+        sep = " %s " % self.reprsymbol
+        return "(" + sep.join(map(str,self.args)) + ")"
+    
+class BoolAnd(BoolOperand):
+    reprsymbol = '&'
+    def __nonzero__(self):
+        for a in self.args:
+            if isinstance(a,basestring):
+                v = eval(a)
+            else:
+                v = bool(a)
+            if not v:
+                return False
+        return True
+
+class BoolOr(BoolOperand):
+    reprsymbol = '|'    
+    def __nonzero__(self):
+        for a in self.args:
+            if isinstance(a,basestring):
+                v = eval(a)
+            else:
+                v = bool(a)
+            if v:
+                return True
+        return False
+
+class BoolNot(BoolOperand):
+    def __init__(self,t):
+        self.arg = t[0][1]
+    def __str__(self):
+        return "~" + str(self.arg)
+    def __nonzero__(self):
+        if isinstance(self.arg,basestring):
+            v = eval(self.arg)
+        else:
+            v = bool(self.arg)
+        return not v
+
+boolOperand = Word(alphas,max=1) | oneOf("True False")
+boolExpr = operatorPrecedence( boolOperand,
+    [
+    ("not", 1, opAssoc.RIGHT, BoolNot),
+    ("and", 2, opAssoc.LEFT,  BoolAnd),
+    ("or",  2, opAssoc.LEFT,  BoolOr),
+    ])
+test = ["p and not q",
+        "not not p",
+        "not(p and q)",
+        "q or not p and r",
+        "q or not p or not r",
+        "q or not (p and r)",
+        "p or q or r",
+        "p or q or r and False",
+        "(p or q or r) and False",
+        ]
+
+p = True
+q = False
+r = True
+print "p =", p
+print "q =", q
+print "r =", r
+print
+for t in test:
+    res = boolExpr.parseString(t)[0]
+    print t,'\n', res, '=', bool(res),'\n'
+