[antlr-interest] Location dependent token?

[Mats Ekberg]

Ok, maybe I was a bit unsharp.
Monetary units are expressed as three-letter words; EUR GBP and so on.
Measurement unitts are also expressed with three letters; TNE KGM and so
on.

The only way to know which is which is where the three letters are
located. In one location its a monetary and another its a measurement.

ok?

regards
mats

mån 2008-12-29 klockan 08:10 -0600 skrev Gary R. Van Sickle:

> > From: Mats Ekberg
> > 
> > Lets say a three letter word in uppercase can mean one of two 
> > tings like:
> > 
> >   10  EUR
> > where EUR means a monetary unit
> >   
> >   10 EUR / TNE
> > where EUR still means a monetary unit but the three letters 
> > TNE now means a measurement uniot.
> > 
> > How can that be expressed in a grammar??
> > 
> > /mats 
> 
> Your question must be missing some information, because what you're asking
> is the most basic of lexing/parsing issues:
> 
> 
> Lexer does something like this:
> 
> NUMBER : [0..9]+ ;
> 
> EUR : 'EUR' ;
> 
> TNE : 'TNE' ;
> 
> 
> Parser does something like this:
> 
> num_with_monetary_unit_and_optional_per_unit
>     : NUMBER monetary_unit ('/' measurement_unit)?
>     ;
> 
> monetary_unit
>     : EUR
>     | <<whatever other monies you support>>
>     ;
> 
> measurement_unit
>     : TNE
>     | <<whatever other measurement units you support>>
>     ;
> 
> 
> But was that really your question?
> 
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