Newbie code review of parsing program Please

[len]

Thanks Paul

I will be going over your code today.  I started looking at Pyparsing
last night
and it just got to late and my brain started to fog over.  I would
really like
to thank you for taking the time to provide me with the code sample
I'm sure it
will really help.  Again thank you very much.

Len

On Nov 17, 8:01 am, Paul McGuire <pt... at austin.rr.com> wrote:
> On Nov 16, 12:53 pm, len <lsumn... at gmail.com> wrote:
>
> > On Nov 16, 12:40 pm, "Mark Tolonen" <M8R-yft... at mailinator.com> wrote:
>
> > > You might want to check out the pyparsing library.
>
> > > -Mark
>
> > Thanks Mark I will check in out right now.
>
> > Len
>
> Len -
>
> Here is a rough pyparsing starter for your problem:
>
> from pyparsing import *
>
> COMP = Optional("USAGE IS") + oneOf("COMP COMPUTATIONAL")
> PIC = oneOf("PIC PICTURE") + Optional("IS")
> PERIOD,LPAREN,RPAREN = map(Suppress,".()")
>
> ident = Word(alphanums.upper()+"_-")
> integer = Word(nums).setParseAction(lambda t:int(t[0]))
> lineNum = Suppress(Optional(LineEnd()) + LineStart() + Word(nums))
>
> rep = LPAREN + integer + RPAREN
> repchars = "X" + rep
> repchars.setParseAction(lambda tokens: ['X']*tokens[1])
> strdecl = Combine(OneOrMore(repchars | "X"))
>
> SIGN = Optional("S")
> repdigits = "9" + rep
> repdigits.setParseAction(lambda tokens: ['9']*tokens[1])
> intdecl = SIGN("sign") + Combine(OneOrMore(repdigits | "9"))
> ("intpart")
> realdecl = SIGN("sign") + Combine(OneOrMore(repdigits | "9"))
> ("intpart") + "V" + \
>                 Combine(OneOrMore("9" + rep | "9"))("realpart")
>
> type = Group((strdecl | realdecl | intdecl) +
>                 Optional(COMP("COMP")))
>
> fieldDecl = lineNum + "05" + ident("name") + \
>                 PIC + type("type") + PERIOD
> structDecl = lineNum + "01" + ident("name") + PERIOD + \
>                 OneOrMore(Group(fieldDecl))("fields")
>
> It prints out:
>
> SALESMEN-RECORD
>    SALESMEN-NO ['999']
>    SALESMEN-NAME ['XXXXXXXXXXXXXXXXXXXXXXXXXXXXXX']
>    SALESMEN-TERRITORY ['XXXXXXXXXXXXXXXXXXXXXXXXXXXXXX']
>    SALESMEN-QUOTA ['S', '9999999', 'COMP']
>    SALESMEN-1ST-BONUS ['S', '99999', 'V', '99', 'COMP']
>    SALESMEN-2ND-BONUS ['S', '99999', 'V', '99', 'COMP']
>    SALESMEN-3RD-BONUS ['S', '99999', 'V', '99', 'COMP']
>    SALESMEN-4TH-BONUS ['S', '99999', 'V', '99', 'COMP']
>
> I too have some dim, dark, memories of COBOL.  I seem to recall having
> to infer from the number of digits in an integer or real what size the
> number would be.  I don't have that logic implemented, but here is an
> extension to the above program, which shows you where you could put
> this kind of type inference logic (insert this code before the call to
> searchString):
>
> class TypeDefn(object):
>     @staticmethod
>     def intType(tokens):
>         self = TypeDefn()
>         self.str = "int(%d)" % (len(tokens.intpart),)
>         self.isSigned = bool(tokens.sign)
>         return self
>     @staticmethod
>     def realType(tokens):
>         self = TypeDefn()
>         self.str = "real(%d.%d)" % (len(tokens.intpart),len
> (tokens.realpart))
>         self.isSigned = bool(tokens.sign)
>         return self
>     @staticmethod
>     def charType(tokens):
>         self = TypeDefn()
>         self.str = "char(%d)" % len(tokens)
>         self.isSigned = False
>         self.isComp = False
>         return self
>     def __repr__(self):
>         return ("+-" if self.isSigned else "") + self.str
> intdecl.setParseAction(TypeDefn.intType)
> realdecl.setParseAction(TypeDefn.realType)
> strdecl.setParseAction(TypeDefn.charType)
>
> This prints:
>
> SALESMEN-RECORD
>    SALESMEN-NO [int(3)]
>    SALESMEN-NAME [char(1)]
>    SALESMEN-TERRITORY [char(1)]
>    SALESMEN-QUOTA [+-int(7), 'COMP']
>    SALESMEN-1ST-BONUS [+-real(5.2), 'COMP']
>    SALESMEN-2ND-BONUS [+-real(5.2), 'COMP']
>    SALESMEN-3RD-BONUS [+-real(5.2), 'COMP']
>    SALESMEN-4TH-BONUS [+-real(5.2), 'COMP']
>
> You can post more questions about pyparsing on the Discussion tab of
> the pyparsing wiki home page.
>
> Best of luck!
> -- Paul