typelevel / typelevel/cats-parse
Backtracking with context
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- Dominant language
- Scala
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- 245
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- 51
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Description
Hi everyone. So i am having this list of parsers in my parser for each case it could possibly have (there is also a recursive parser above which uses this list of parsers for each next node and a lot of simple parsers inside each):
parser1.withContext("parser 1").backtrack |
parser2.withContext("parser 2").backtrack |
parser3.withContext("parser 3")
The problem is - i never getting any context except of "parser 3". I wonder if there is some trick to get output like:
Left(Error(4,NonEmptyList(
WithContext(parser 2,
WithContext(parser 3,EndOfString(4,27))
)
)))
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
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Research direction
Start by tracing the parser1/parser2/parser3 chain, including withContext, backtrack, and the recursive parser described in the issue. Check how the resulting Left(Error(...)) is assembled and compare it with the requested nested WithContext output. Done means establishing whether the requested context is supported and, if so, adding a focused regression test for that behavior.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- scala
- Domain
- compilers
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 25/100