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Diffstat (limited to 'src/examples/sexpParser.py')
| -rw-r--r-- | src/examples/sexpParser.py | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/src/examples/sexpParser.py b/src/examples/sexpParser.py new file mode 100644 index 0000000..c67b6f8 --- /dev/null +++ b/src/examples/sexpParser.py @@ -0,0 +1,167 @@ +# sexpParser.py
+#
+# Demonstration of the pyparsing module, implementing a simple S-expression
+# parser.
+#
+# Updates:
+# November, 2011 - fixed errors in precedence of alternatives in simpleString;
+# fixed exception raised in verifyLen to properly signal the input string
+# and exception location so that markInputline works correctly; fixed
+# definition of decimal to accept a single '0' and optional leading '-'
+# sign; updated tests to improve parser coverage
+#
+# Copyright 2007-2011, by Paul McGuire
+#
+"""
+BNF reference: http://theory.lcs.mit.edu/~rivest/sexp.txt
+
+<sexp> :: <string> | <list>
+<string> :: <display>? <simple-string> ;
+<simple-string> :: <raw> | <token> | <base-64> | <hexadecimal> |
+ <quoted-string> ;
+<display> :: "[" <simple-string> "]" ;
+<raw> :: <decimal> ":" <bytes> ;
+<decimal> :: <decimal-digit>+ ;
+ -- decimal numbers should have no unnecessary leading zeros
+<bytes> -- any string of bytes, of the indicated length
+<token> :: <tokenchar>+ ;
+<base-64> :: <decimal>? "|" ( <base-64-char> | <whitespace> )* "|" ;
+<hexadecimal> :: "#" ( <hex-digit> | <white-space> )* "#" ;
+<quoted-string> :: <decimal>? <quoted-string-body>
+<quoted-string-body> :: "\"" <bytes> "\""
+<list> :: "(" ( <sexp> | <whitespace> )* ")" ;
+<whitespace> :: <whitespace-char>* ;
+<token-char> :: <alpha> | <decimal-digit> | <simple-punc> ;
+<alpha> :: <upper-case> | <lower-case> | <digit> ;
+<lower-case> :: "a" | ... | "z" ;
+<upper-case> :: "A" | ... | "Z" ;
+<decimal-digit> :: "0" | ... | "9" ;
+<hex-digit> :: <decimal-digit> | "A" | ... | "F" | "a" | ... | "f" ;
+<simple-punc> :: "-" | "." | "/" | "_" | ":" | "*" | "+" | "=" ;
+<whitespace-char> :: " " | "\t" | "\r" | "\n" ;
+<base-64-char> :: <alpha> | <decimal-digit> | "+" | "/" | "=" ;
+<null> :: "" ;
+"""
+
+from pyparsing import *
+from base64 import b64decode
+import pprint
+
+def verifyLen(s,l,t):
+ t = t[0]
+ if t.len is not None:
+ t1len = len(t[1])
+ if t1len != t.len:
+ raise ParseFatalException(s,l,\
+ "invalid data of length %d, expected %s" % (t1len, t.len))
+ return t[1]
+
+# define punctuation literals
+LPAR, RPAR, LBRK, RBRK, LBRC, RBRC, VBAR = map(Suppress, "()[]{}|")
+
+decimal = Regex(r'0|[1-9]\d*').setParseAction(lambda t: int(t[0]))
+hexadecimal = ("#" + OneOrMore(Word(hexnums)) + "#")\
+ .setParseAction(lambda t: int("".join(t[1:-1]),16))
+bytes = Word(printables)
+raw = Group(decimal("len") + Suppress(":") + bytes).setParseAction(verifyLen)
+token = Word(alphanums + "-./_:*+=")
+base64_ = Group(Optional(decimal|hexadecimal,default=None)("len") + VBAR
+ + OneOrMore(Word( alphanums +"+/=" )).setParseAction(lambda t: b64decode("".join(t)))
+ + VBAR).setParseAction(verifyLen)
+
+qString = Group(Optional(decimal,default=None)("len") +
+ dblQuotedString.setParseAction(removeQuotes)).setParseAction(verifyLen)
+simpleString = base64_ | raw | decimal | token | hexadecimal | qString
+
+# extended definitions
+decimal = Regex(r'-?0|[1-9]\d*').setParseAction(lambda t: int(t[0]))
+real = Regex(r"[+-]?\d+\.\d*([eE][+-]?\d+)?").setParseAction(lambda tokens: float(tokens[0]))
+token = Word(alphanums + "-./_:*+=!<>")
+
+simpleString = real | base64_ | raw | decimal | token | hexadecimal | qString
+
+display = LBRK + simpleString + RBRK
+string_ = Optional(display) + simpleString
+
+sexp = Forward()
+sexpList = Group(LPAR + ZeroOrMore(sexp) + RPAR)
+sexp << ( string_ | sexpList )
+
+######### Test data ###########
+test00 = """(snicker "abc" (#03# |YWJj|))"""
+test01 = """(certificate
+ (issuer
+ (name
+ (public-key
+ rsa-with-md5
+ (e 15 |NFGq/E3wh9f4rJIQVXhS|)
+ (n |d738/4ghP9rFZ0gAIYZ5q9y6iskDJwASi5rEQpEQq8ZyMZeIZzIAR2I5iGE=|))
+ aid-committee))
+ (subject
+ (ref
+ (public-key
+ rsa-with-md5
+ (e |NFGq/E3wh9f4rJIQVXhS|)
+ (n |d738/4ghP9rFZ0gAIYZ5q9y6iskDJwASi5rEQpEQq8ZyMZeIZzIAR2I5iGE=|))
+ tom
+ mother))
+ (not-before "1997-01-01_09:00:00")
+ (not-after "1998-01-01_09:00:00")
+ (tag
+ (spend (account "12345678") (* numeric range "1" "1000"))))
+"""
+test02 = """(lambda (x) (* x x))"""
+test03 = """(def length
+ (lambda (x)
+ (cond
+ ((not x) 0)
+ ( t (+ 1 (length (cdr x))))
+ )
+ )
+)
+"""
+test04 = """(2:XX "abc" (#03# |YWJj|))"""
+test05 = """(if (is (window_name) "XMMS") (set_workspace 2))"""
+test06 = """(if
+ (and
+ (is (application_name) "Firefox")
+ (or
+ (contains (window_name) "Enter name of file to save to")
+ (contains (window_name) "Save As")
+ (contains (window_name) "Save Image")
+ ()
+ )
+ )
+ (geometry "+140+122")
+)
+"""
+test07 = """(defun factorial (x)
+ (if (zerop x) 1
+ (* x (factorial (- x 1)))))
+ """
+test51 = """(2:XX "abc" (#30# |YWJj|))"""
+test51error = """(3:XX "abc" (#30# |YWJj|))"""
+
+test52 = """
+ (and
+ (or (> uid 1000)
+ (!= gid 20)
+ )
+ (> quota 5.0e+03)
+ )
+ """
+
+# Run tests
+t = None
+alltests = [ locals()[t] for t in sorted(locals()) if t.startswith("test") ]
+
+for t in alltests:
+ print '-'*50
+ print t
+ try:
+ sexpr = sexp.parseString(t, parseAll=True)
+ pprint.pprint(sexpr.asList())
+ except ParseFatalException, pfe:
+ print "Error:", pfe.msg
+ print pfe.markInputline('^')
+ print
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