diff options
| author | Cengiz Kaygusuz <cngkaygusuz@gmail.com> | 2017-11-20 20:46:39 -0500 |
|---|---|---|
| committer | Cengiz Kaygusuz <cngkaygusuz@gmail.com> | 2017-11-20 20:46:39 -0500 |
| commit | 27e183a78c8062ed7c2bbb91655a5e56cd697bba (patch) | |
| tree | 88fd355a0cc6da4c130582e092d702836596cbb2 /examples/scanExamples.py | |
| parent | 4ba589cf13588e90992e23deb5a9784340efd2cc (diff) | |
| download | pyparsing-git-27e183a78c8062ed7c2bbb91655a5e56cd697bba.tar.gz | |
Move src to root
Diffstat (limited to 'examples/scanExamples.py')
| -rw-r--r-- | examples/scanExamples.py | 75 |
1 files changed, 75 insertions, 0 deletions
diff --git a/examples/scanExamples.py b/examples/scanExamples.py new file mode 100644 index 0000000..24ae0e7 --- /dev/null +++ b/examples/scanExamples.py @@ -0,0 +1,75 @@ +#
+# scanExamples.py
+#
+# Illustration of using pyparsing's scanString,transformString, and searchString methods
+#
+# Copyright (c) 2004, 2006 Paul McGuire
+#
+from pyparsing import Word, alphas, alphanums, Literal, restOfLine, OneOrMore, \
+ empty, Suppress, replaceWith
+
+# simulate some C++ code
+testData = """
+#define MAX_LOCS=100
+#define USERNAME = "floyd"
+#define PASSWORD = "swordfish"
+
+a = MAX_LOCS;
+CORBA::initORB("xyzzy", USERNAME, PASSWORD );
+
+"""
+
+#################
+print("Example of an extractor")
+print("----------------------")
+
+# simple grammar to match #define's
+ident = Word(alphas, alphanums+"_")
+macroDef = Literal("#define") + ident.setResultsName("name") + "=" + restOfLine.setResultsName("value")
+for t,s,e in macroDef.scanString( testData ):
+ print(t.name,":", t.value)
+
+# or a quick way to make a dictionary of the names and values
+# (return only key and value tokens, and construct dict from key-value pairs)
+# - empty ahead of restOfLine advances past leading whitespace, does implicit lstrip during parsing
+macroDef = Suppress("#define") + ident + Suppress("=") + empty + restOfLine
+macros = dict(list(macroDef.searchString(testData)))
+print("macros =", macros)
+print()
+
+
+#################
+print("Examples of a transformer")
+print("----------------------")
+
+# convert C++ namespaces to mangled C-compatible names
+scopedIdent = ident + OneOrMore( Literal("::").suppress() + ident )
+scopedIdent.setParseAction(lambda t: "_".join(t))
+
+print("(replace namespace-scoped names with C-compatible names)")
+print(scopedIdent.transformString( testData ))
+
+
+# or a crude pre-processor (use parse actions to replace matching text)
+def substituteMacro(s,l,t):
+ if t[0] in macros:
+ return macros[t[0]]
+ident.setParseAction( substituteMacro )
+ident.ignore(macroDef)
+
+print("(simulate #define pre-processor)")
+print(ident.transformString( testData ))
+
+
+
+#################
+print("Example of a stripper")
+print("----------------------")
+
+from pyparsing import dblQuotedString, LineStart
+
+# remove all string macro definitions (after extracting to a string resource table?)
+stringMacroDef = Literal("#define") + ident + "=" + dblQuotedString + LineStart()
+stringMacroDef.setParseAction( replaceWith("") )
+
+print(stringMacroDef.transformString( testData ))
|