Module `error`

Error management

Errors are designed with multiple needs in mind:

Accumulate more [context][Parser::context] as the error goes up the parser chain
Distinguish between [recoverable errors, unrecoverable errors, and more data is needed][ErrMode]
Have a very low overhead, as errors are often discarded by the calling parser (examples: repeat, alt)
Can be modified according to the user's needs, because some languages need a lot more information
Help thread-through the [stream][crate::stream]

To abstract these needs away from the user, generally winnow parsers use the ModalResult alias, rather than Result. Parser::parse is a top-level operation that can help convert to a Result for integrating with your application's error reporting.

Error types include:

EmptyError when the reason for failure doesn't matter
ContextError
InputError (mostly for testing)
TreeError (mostly for testing)
[Custom errors][crate::_topic::error]

Structs

ContextError Accumulate context while backtracking errors
EmptyError Track an error occurred without any other StrContext
InputError Capture input on error
ParseError See Parser::parse

Enums

ErrMode Add parse error state to ParserErrors
Needed Contains information on needed data if a parser returned Incomplete
StrContext Additional parse context for ContextError added via Parser::context
StrContextValue See StrContext

Traits

AddContext Used by Parser::context to add custom data to error while backtracking
ErrorConvert Equivalent of From implementation to avoid orphan rules in bits parsers
FromExternalError Create a new error with an external error, from std::str::FromStr
ModalError Manipulate the how parsers respond to this error
ParserError The basic Parser trait for errors

Type Aliases

ModalResult [Modal error reporting][ErrMode] for Parser::parse_next
Result By default, the error type (E) is ContextError.