Packages

  • package root
    Definition Classes
    root
  • package parsley
    Definition Classes
    root
  • package errors

    This package contains various functionality relating to the generation and formatting of error messages.

    This package contains various functionality relating to the generation and formatting of error messages.

    In particular, it includes a collection of combinators for improving error messages within the parser, including labelling and providing additional information. It also contains combinators that can be used to valid data produced by a parser, to ensure it conforms to expected invariances, producing good quality error messages if this is not the case. Finally, this package contains ways of changing the formatting of error messages: this can either be changing how the default String-based errors are formatted, or by injectiing Parsley's errors into a custom error object.

    Definition Classes
    parsley
  • package tokenextractors

    This package contains implementations of token extractors that can be mixed into ErrorBuilder to decide how to extract unexpected tokens from the residual input left over from a parse error.

    This package contains implementations of token extractors that can be mixed into ErrorBuilder to decide how to extract unexpected tokens from the residual input left over from a parse error.

    These are common strategies, and something here is likely to be what is needed. They are all careful to handle unprintable characters and whitespace in a sensible way, and account for unicode codepoints that are wider than a single 16-bit character.

    Definition Classes
    errors
    Since

    4.0.0

  • DefaultErrorBuilder
  • ErrorBuilder
  • Token
  • TokenSpan
  • combinator
o

parsley.errors

combinator

object combinator

This module contains combinators that can be used to directly influence error messages of parsers.

Error messages are, by default, not particularly descriptive. However, the combinators in this module can be used to improve the generation of error messages by providing labels for expected items, explanations for why things went wrong, custom error messages, custom unexpected error messages, as well as correcting the offsets that error messages actually occurred at.

Source
combinator.scala
Since

3.0.0

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Type Members

  1. implicit final class ErrorMethods[P, +A] extends AnyRef

    This class exposes helpful combinators that are specialised for generating more helpful errors messages.

    This class exposes helpful combinators that are specialised for generating more helpful errors messages.

    This extension class operates on values that are convertible to parsers. It enables the use of error combinators, which can be used for data validation, error annotation, or immediate failing.

    P

    the type of base value that this class is used on (the conversion to Parsley) is summoned automatically.

    Version

    3.0.0

Value Members

  1. final def !=(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  2. final def ##(): Int
    Definition Classes
    AnyRef → Any
  3. final def ==(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  4. def amend[A](p: Parsley[A]): Parsley[A]

    This combinator adjusts any error messages generated by the given parser so that they occur at the position recorded on entry to this combinator (effectively as if no input were consumed).

    This combinator adjusts any error messages generated by the given parser so that they occur at the position recorded on entry to this combinator (effectively as if no input were consumed).

    This is useful if validation work is done on the output of a parser that may render it invalid, but the error should point to the beginning of the structure. This combinators effect can be cancelled with entrench.

    p

    a parser whose error messages should be adjusted.

    returns

    a parser that parses p but ensures any errors generated occur as if no input were consumed.

    Since

    3.1.0

  5. final def asInstanceOf[T0]: T0
    Definition Classes
    Any
  6. def clone(): AnyRef
    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws( ... ) @native()
  7. def entrench[A](p: Parsley[A]): Parsley[A]

    This combinator prevents the action of any enclosing amend on the errors generated by the given parser.

    This combinator prevents the action of any enclosing amend on the errors generated by the given parser.

    Sometimes, the error adjustments performed by amend should only affect errors generated within a certain part of a parser and not the whole thing; in this case, entrench can be used to protect sub-parsers from having their errors adjusted, providing a much more fine-grained scope for error adjustment.

    p

    a parser whose error messages should not be adjusted by any surrounding amend.

    returns

    a parser that parses p but ensures any error messages are generated normally.

    Example:

    1. In this example, the ident parser should not allow keywords, and these error messages should be generated from the start of the identifier, not the end. However any errors generated within the identifier itself should remain at their regular offsets.

      val ident = amend {
    entrench(stringOfSome(letter)).filterOut {
        case v if keywords.contains(v) => s"keyword $v cannot be an identifier"
    }
}
    Since

    3.1.0

  8. final def eq(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  9. def equals(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  10. def fail(caretWidth: Int, msg0: String, msgs: String*): Parsley[Nothing]

    This combinator consumes no input and fails immediately with the given error messages.

    This combinator consumes no input and fails immediately with the given error messages.

    Produces a specialised error message where all the lines of the error are the given msgs in order of appearance.

    caretWidth

    the size of the caret for this error: should ideally match the width of the cause of the error.

    msg0

    the first message in the error message.

    msgs

    the remaining messages that will make up the error message.

    returns

    a parser that fails producing an error message consisting of all the given messages.

    Example: 

    1. val failing = fail("hello,", "this is an error message", "broken across multiple lines")
    Since

    4.0.0

  11. def fail(msg0: String, msgs: String*): Parsley[Nothing]

    This combinator consumes no input and fails immediately with the given error messages.

    This combinator consumes no input and fails immediately with the given error messages.

    Produces a specialised error message where all the lines of the error are the given msgs in order of appearance.

    msg0

    the first message in the error message.

    msgs

    the remaining messages that will make up the error message.

    returns

    a parser that fails producing an error message consisting of all the given messages.

    Example: 

    1. val failing = fail("hello,", "this is an error message", "broken across multiple lines")
    Since

    3.0.0

  12. def finalize(): Unit
    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws( classOf[java.lang.Throwable] )
  13. final def getClass(): Class[_]
    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  14. def hashCode(): Int
    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  15. final def isInstanceOf[T0]: Boolean
    Definition Classes
    Any
  16. def markAsToken[A](p: Parsley[A]): Parsley[A]

    This combinator marks any errors within the given parser as being lexical errors.

    This combinator marks any errors within the given parser as being lexical errors.

    When an error is marked as a lexical error, it sets a flag within the error that is passed to ErrorBuilder.unexpectedToken: this should be used to prevent Lexer-based token extraction from being performed on an error, since lexing errors cannot be the result of unexpected tokens.

    p

    the parser that serves as a token.

    returns

    a parser that parses p but ensures any error messages are marked as lexical errors.

    Since

    4.0.0

  17. final def ne(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  18. final def notify(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native()
  19. final def notifyAll(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native()
  20. final def synchronized[T0](arg0: ⇒ T0): T0
    Definition Classes
    AnyRef
  21. def toString(): String
    Definition Classes
    AnyRef → Any
  22. def unexpected(caretWidth: Int, item: String): Parsley[Nothing]

    This combinator consumes no input and fails immediately, setting the unexpected component to the given item.

    This combinator consumes no input and fails immediately, setting the unexpected component to the given item.

    Produces a trivial error message where the unexpected component of the error is replaced with the given item item.

    caretWidth

    the size of the caret for this error: should ideally match the width of the cause of the error (the unexpected item).

    item

    the unexpected message for the error generated.

    returns

    a parser that fails producing an error with item as the unexpected token.

    Since

    4.0.0

  23. def unexpected(item: String): Parsley[Nothing]

    This combinator consumes no input and fails immediately, setting the unexpected component to the given item.

    This combinator consumes no input and fails immediately, setting the unexpected component to the given item.

    Produces a trivial error message where the unexpected component of the error is replaced with the given item item.

    item

    the unexpected message for the error generated.

    returns

    a parser that fails producing an error with item as the unexpected token.

    Since

    3.0.0

  24. final def wait(): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  25. final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  26. final def wait(arg0: Long): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... ) @native()

Inherited from AnyRef

Inherited from Any

Failure Combinators

These combinator immediately fail the parser, with a more bespoke message.

Error Extension Combinators

These are implicit classes that, when in scope, enable additional combinators on parsers that interact with the error system in some way.

Error Adjustment Combinators

These combinators can affect at what position an error is caused at. They are opposites: where amend will ensure an error message is said to have generated at the position on entry to the combinator, entrench will resist these changes.

Ungrouped