[antlr-interest] Clarifications on grammar rules.
Bharath S
payasam79 at yahoo.com
Wed Apr 7 06:24:56 PDT 2004
Hi Ter,
I need to have a rule called time units, lets say,
that can be any unit (seconds or days or minutes..).
----------------------------
Test: "Time:"(Secs|Days|mins|hours);
----------------------------
is required for the same purpose. If I have "Test" as
my lexer rule, I want the user to enter any time unit
and I should be able to parse it and print out a
result that looks like:
___________________________
Time: 25s
(or)
Time: 12d
---------------------------
and so on. Also each of the time units work perfectly
when I test them alone.
Thanks Ter.
--- Terence Parr <parrt at cs.usfca.edu> wrote:
>
> On Apr 6, 2004, at 2:08 PM, Bharath S wrote:
> > I have a rule of the form:
> > ----------------------------------------
> > Time: ('0'..'9')+
> > ('d'{$setType(Days);} | 's'{$setType(Secs);}
> > | {$setType(INT);}) ;
> >
> > and
> > -------------------------
> > protected Days: INT('d');
> > protected Secs: INT('s');
> > protected INT: ('0'..'9')+;
> > ---------------------------
> > When I try "Test: Secs|Days", I get a
> non-determinism
> > warning and it makes sense because both rules have
> > common left prefixes. However, I have no clue to
> how I
> > can fix it. If I write a separate rule to remove
> > common prefixes in "Secs" and "Days", it conflicts
> > with the above rule, "Time". Am I missing
> something
> > obvious?
>
> Hi.
>
> I'm not sure what you are trying to match here.
> What do you mean here:
>
> > When I try "Test: Secs|Days", I get a
> non-determinism
>
> Thanks,
> Ter
> --
> Professor Comp. Sci., University of San Francisco
> Creator, ANTLR Parser Generator,
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=====
Bharath Sundararaman
Graduate Assistant, CAHS.
(312)-5606532 (M)
http://www.cs.uic.edu/~bsundara
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