[antlr-interest] anybody help with me a python grammar rule?
Terence Parr
parrt at cs.usfca.edu
Sat Feb 21 18:29:01 PST 2004
For example, won't this rule generate the same language?
parameter_list:
defparameter (',' defparameter)*
( ','
('*' NAME [',' '**' NAME] | '**' NAME
)
)
| '*' NAME [',' '**' NAME]
| '**' NAME
and it's LL(1).
arglist has the same problem. I wonder what kinda parser they build
from this grammar. Ick.
Ter
On Feb 21, 2004, at 6:10 PM, Terence Parr wrote:
> Folks, the formal parameter list for functions looks wacky in the
> distribution and on the net.
>
> First the grammar in the distribution:
>
> varargslist: (fpdef ['=' test] ',')* ('*' NAME [',' '**' NAME] | '**'
> NAME) | fpdef ['=' test] (',' fpdef ['=' test])* [',']
> fpdef: NAME | '(' fplist ')'
> fplist: fpdef (',' fpdef)* [',']
>
> The one from the doc is
>
> parameter_list ::=
> (defparameter ",")*
> ("*" identifier [, "**" identifier]
> | "**" identifier
> | defparameter [","])
>
> defparameter ::=
> parameter ["=" expression]
>
> sublist ::=
> parameter ("," parameter)* [","]
>
> parameter ::=
> identifier | "(" sublist ")"
>
> My question here is why have the final '| defparameter [","]' alt in
> parameter_list???? Surely it's redundant (might have to move a comma,
> but...)
>
> Can anybody give me some examples of the various things parameters
> might look like in the wacky cases?
>
> Thanks!
>
> --
> Professor Comp. Sci., University of San Francisco
> Creator, ANTLR Parser Generator, http://www.antlr.org
> Cofounder, http://www.jguru.com
> Cofounder, http://www.knowspam.net enjoy email again!
> Cofounder, http://www.peerscope.com pure link sharing
>
>
>
>
>
>
> Yahoo! Groups Links
>
>
>
>
>
>
--
Professor Comp. Sci., University of San Francisco
Creator, ANTLR Parser Generator, http://www.antlr.org
Cofounder, http://www.jguru.com
Cofounder, http://www.knowspam.net enjoy email again!
Cofounder, http://www.peerscope.com pure link sharing
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