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diff --git a/src/examples/macroExpander.py b/src/examples/macroExpander.py
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+# macroExpander.py
+#
+# Example pyparsing program for performing macro expansion, similar to 
+# the C pre-processor.  This program is not as fully-featured, simply
+# processing macros of the form:
+#     #def xxx yyyyy
+# and replacing xxx with yyyyy in the rest of the input string.  Macros
+# can also be composed using other macros, such as
+#     #def zzz xxx+1
+# Since xxx was previously defined as yyyyy, then zzz will be replaced
+# with yyyyy+1.
+#
+# Copyright 2007 by Paul McGuire
+#
+from pyparsing import *
+
+# define the structure of a macro definition (the empty term is used 
+# to advance to the next non-whitespace character)
+macroDef = "#def" + Word(alphas+"_",alphanums+"_").setResultsName("macro") + \
+                empty + restOfLine.setResultsName("value")
+                
+# define a placeholder for defined macros - initially nothing
+macroExpr = Forward()
+
+# global dictionary for macro definitions
+macros = {}
+
+# parse action for macro definitions
+def processMacroDefn(s,l,t):
+    macroVal = macroExpander.transformString(t.value)
+    macros[t.macro] = macroVal
+    macroExpr << MatchFirst( map(Keyword,macros.keys()) )
+    return "#def " + t.macro + " " + macroVal
+
+# parse action to replace macro references with their respective definition
+def processMacroRef(s,l,t):
+    return macros[t[0]]
+
+# attach parse actions to expressions
+macroExpr.setParseAction(processMacroRef)
+macroDef.setParseAction(processMacroDefn)
+
+# define pattern for scanning through the input string
+macroExpander = macroExpr | macroDef
+
+
+
+# test macro substitution using transformString
+testString = """
+    #def A 100
+    #def ALEN A+1
+
+    char Astring[ALEN];
+    char AA[A];
+    typedef char[ALEN] Acharbuf;
+    """
+
+print macroExpander.transformString(testString)
+print macros