Do we know if that's ambiguous? Don't we have to run it 
through Marpa::R2::ASF to know?



On Wednesday, 3 September 2014 20:10:42 UTC+10, rns wrote:
>
> Can you please look at this gist 
> <https://gist.github.com/rns/fb6abf62a5fa779957ba>? The result is in the 
> comment below it. This might be a solution provided that I've got the right 
> idea.
>
>
>
>
>
>
> On Wed, Sep 3, 2014 at 11:44 AM, Andrew Dunbar <[email protected] 
> <javascript:>> wrote:
>
>> I've come back to Perl after a long absence just to play with Marpa 
>> because it looks like the most full featured Earley parser in any of the 
>> programming languages I know.
>>
>> I'm interested in Earley specifically because it can handle ambiguity and 
>> can produce a parse forest.
>>
>> I'm using it to investigate the syllable structure of the writing system 
>> of the Lao language of Southeast Asia. Specifically to see whether it's 
>> inherently ambiguous, and how.
>>
>> So far it works great and I'm glad I've come here from the Bison and PEG 
>> grammars I was playing with earlier.
>>
>> But it seems that there might be two kinds of ambiguities, the kind I'm 
>> looking for, and a kind that might be an artefact of Earley parsing or of 
>> the way I've written the grammar.
>>
>> Without having to teach you Lao I'll attempt to analogize:
>>
>> All ::= Syllable+
>>
>> Syllable ::= C V C
>>          | C V
>>          | C
>>
>> C ~ [bcdfghjklmnpqrstvwxyz]
>> V ~ [aeiou]
>>
>>
>> The "Syllable ::= C" rule is to allow lone initial consonants, as are 
>> used occasionally for abbreviations.
>>
>> If my input string is "mat" I only want:
>>  
>> (Syllable (C m) (V a) (C t))
>>
>> But due to the abbreviation rule I also get a second unwanted parse:
>>
>> (Syllable (C m) (V a))
>> (Syllable (C t))
>>
>> I've been able to refactor my grammar to deal with other issues that have 
>> appeared, by I can't seem to think of anything which accounts for 
>> occasional abbreviations but doesn't generate a number of unwanted 
>> alternative parses.
>>
>> Can I refactor my grammar or is there some other way to deal with this 
>> but still generate all the other kinds of ambiguity that I am interested in?
>>
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>
>

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