Is ooRexx context free?  It seems to be that it isn't, but I could be  
wrong.  Very thin in knowledge in this area.

Bruce
On Apr 23, 2010, at 10:35 AM, Gil Barmwater wrote:

> I seem to remember that the ANSI standard has (classic) Rexx in BNF.
> You can get a PDF here:
>
> http://www.rexxla.org/rexxlang/standards/j18pub.pdf
>
> Moritz Hoffmann wrote:
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>> Hi,
>>
>> I'm currently trying to write a grammar for ooRexx to build a  
>> workbench
>> on it. However, I face some problems.
>>
>> The grammar requires to be context free, and have no left recursions.
>> Internally, it will use ANTLR to do the parsing, which is a LR(*).
>>
>> First, I face some problem tokenizing the input, but that' snot the
>> biggest issue yet. I will ask about that again.
>>
>> The main issue is to parse expressions. I had a look at the ooRexx
>> source code to figure out how it does it, but it's complex.
>>
>> So, I'm asking for help regarding a single example in ebnf to parse  
>> some
>> expression, including precedence and such.
>>
>> The problem that ooRexx uses token sub-types is mostly solved. This  
>> is
>> that words like "if" are keywords at some places and just symbols at
>> other places. Due to this, all keywords have to be recognized as  
>> symbols
>> as well.
>>
>> The grammar that is currently in the SVN, has some bugs - and they're
>> hard to figure out...
>>
>> Kind regards,
>> Moritz
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>
> -- 
> Gil Barmwater
>
>
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