[TxMt] Re: Parameter-list RE in a grammar

[Allan Odgaard]

On 5 Sep 2008, at 23:10, Fritz Anderson wrote:

> I'm building up a grammar for the Confluence wiki markup, and I'm
> having trouble with tags that take a list of parameters.
>
> Tags look like this (all strings are examples only):
>
> {noparams}
> {oneparam:key=10}
> {twoparams:keyOne=value|keyTwo=2%}
> {threeparams:keyA=a value|keyB=another value|keyC=a third value}
> [...] Could someone enlighten me, please?

You can’t get proper scopes assigned to each item of a variable length  
list using just one match, so you need to change strategy and use  
begin/end rules, like in this example:

     {   comment = 'match a tag with parameters';
         begin = '{\w+:';
         end = '}';
         patterns = (
             {   comment = 'match one parameter in the list';
                 match = '\w+\|[^\|}]*';
             }
         );
     }

The above rule only handles tags with arguments, I would probably do a  
separate rule for tags without arguments to keep it simple.