Repository navigation
Remember the furthest failure when backtracking - #19
Merged
Merged
Conversation
`oneOf` already reported the furthest of its alternatives' failures, but failures were not kept across successful parses, so deeper problems were obscured whenever a shorter alternative succeeded in `oneOf`, even if the parse ultimately failed in an outer parser. In practice this meant reported error positions/messages were often far removed from the actual mistake, and any parse that stopped early would unhelpfully report "excess content followed valid input". `Success` now has a `furthestFailure` property whose value is what ultimately gets reported by combinators like `lookaheadNot` and `butNot`, as well as by `parse` itself. This may be a breaking change if you have hand-written parsers.
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
oneOfalready reported the furthest of its alternatives' failures, but failures were not kept across successful parses, so deeper problems were obscured whenever a shorter alternative succeeded inoneOf, even if the parse ultimately failed in an outer parser.In practice this meant reported error positions/messages were often far removed from the actual mistake, and any parse that stopped early would unhelpfully report "excess content followed valid input".
Successnow has afurthestFailureproperty whose value is what ultimately gets reported by combinators likelookaheadNotandbutNot, as well as byparseitself.This may be a breaking change if you have hand-written parsers.