[antlr-interest] Block Returning Value in ANTLR
Bryan Ewbank
ewbank at gmail.com
Fri Apr 1 06:53:49 PST 2005
There's several ways to specify a default for xy:
/**
* initialize in declaration
*/
range_opt returns [pair<int,int> xy = ... ]
:
( xy=range )?
;
/**
* initialize in preamble
*/
range_opt returns [pair<int,int> xy]
{ xy = ... ; }
:
( xy=range ) ?
;
/**
* initialize in alternative - note that
* the ()? is replaced with ( | )
*/
range_opt returns [pair<int,int> xy]
:
( /* nothing here */
{ xy = ...; }
| xy=range
)
;
On Apr 1, 2005 9:08 AM, Shalini Sharma <shalini.sh at gmail.com> wrote:
> range_opt returns [pair<int,int> xy] : (xy=range)? ;
>
> i want to specify xy= some deafult value in case range is empty
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