[antlr-interest] The right way to invoke templates with nullarguments?

Terence Parr parrt at cs.usfca.edu
Fri Jun 22 00:10:24 PDT 2007

On Jun 22, 2007, at 11:02 AM, Diehl, Matthew J wrote:

>> (have to have a cumbersome conditional in there).
> I've decided (I'm new though) that the best way to setup your
> 'cumbersome conditional' is whenever there's a conditional part,  
> set it
> equal to something (s2 like you did below), and then in the
> StringTemplate section, define it as:
> stat2={s2!=null?$s2.st:false}


> Instead of false, you can also probably try null.


>   This allows you so
> that when you write the group file, <if(stat1)>other  
> stuff<stat1><endif>
> can be used as well.  When I was setting it as:
> stat2={s2!=null?$s2.st:""} it would always return true for
> <if(stat1)><endif> since it was not null or false,

correct "" is a present attribute so IF evals to true on that.

Set it to null :)


More information about the antlr-interest mailing list