Hi Konrad,
A somewhat similar issue is present in an XML grammar: the closing element must
match the opening element. In PPXmlGrammar, you have a condition that matches
it and throws a failure otherwise:
element
"[39] element ::= EmptyElemTag | STag content
ETag"
^ $< asParser , qualified , attributes , whitespace optional , ('/>'
asParser / ($> asParser , content , [ :stream | stream position ] asParser ,
'</' asParser , qualified , whitespace optional , $> asParser)) ==> [ :nodes |
nodes fifth = '/>'
ifTrue: [ Array with: nodes second with: nodes third
with: #() ]
ifFalse: [
nodes second = nodes fifth fifth
ifTrue: [ Array with: nodes second
with: nodes third with: nodes fifth second ]
ifFalse: [ PPFailure message: 'Expected
</' , nodes second qualifiedName , '>' context: nil at: nodes fifth third ] ] ]
Cheers,
Doru
> On Jan 27, 2019, at 4:38 PM, Konrad Hinsen <[email protected]> wrote:
>
> Dear Tomo,
>
>> This post might help you. In case of PetitParser2, it's PP2Failure instead
>> of PPFailure.
>> https://stackoverflow.com/questions/15371334/how-can-a-petitparser-parse-rule-signal-an-error
>
> That's indeed a possible solution: parse for arbitrary operators, and then
> add a test for equality that can make everything fail in the end. I will try
> it out!
>
> Thanks,
> Konrad.
>
>
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