Packages

  • package root
    Definition Classes
    root
  • package parsley
    Definition Classes
    root
  • package token

    This package provides a wealth of functionality for performing common lexing tasks.

    This package provides a wealth of functionality for performing common lexing tasks.

    It is organised as follows:

    • the main parsing functionality is accessed via Lexer, which provides implementations for the combinators found in the sub-packages given a LexicalDesc.
    • the descriptions sub-package is how a lexical structure can be described, providing the configuration that alters the behaviour of the parsers produced by the Lexer.
    • the other sub-packages contain the high-level interfaces that the Lexer exposes, which can be used to pass whitespace-aware and non-whitespace-aware combinators around in a uniform way.
    • the predicate module contains functionality to help define boolean predicates on characters or unicode codepoints.
    Definition Classes
    parsley
  • class Lexer extends AnyRef

    This class provides a large selection of functionality concerned with lexing.

    This class provides a large selection of functionality concerned with lexing.

    This class provides lexing functionality to parsley, however it is guaranteed that nothing in this class is not implementable purely using parsley's pre-existing functionality. These are regular parsers, but constructed in such a way that they create a clear and logical separation from the rest of the parser.

    The class is broken up into several internal "modules" that group together similar kinds of functionality. Importantly, the lexemes and nonlexemes objects separate the underlying token implementations based on whether or not they consume whitespace or not. Functionality is broadly duplicated across both of these modules: lexemes should be used by a wider parser, to ensure whitespace is handled uniformly; and nonlexemes should be used to define further composite tokens or in special circumstances where whitespace should not be consumed.

    It is possible that some of the implementations of parsers found within this class may have been hand-optimised for performance: care will have been taken to ensure these implementations precisely match the semantics of the originals.

    Definition Classes
    token
    Annotations
    @deprecatedInheritance( ... , "4.1.0" )
  • lexeme
  • nonlexeme
  • space
o

parsley.token.Lexer

nonlexeme

object nonlexeme

This object is concerned with non-lexemes: these are tokens that do not give any special treatment to whitespace.

Whilst the functionality in lexeme is strongly recommended for wider use in a parser, the functionality here may be useful for more specialised use-cases. In particular, these may for the building blocks for more complex tokens (where whitespace is not allowed between them, say), in which case these compound tokens can be turned into lexemes manually. For example, the lexer does not have configuration for trailing specifiers on numeric literals (like, 1024L in Scala, say): the desired numeric literal parser could be extended with this functionality before whitespace is consumed by using the variant found in this object.

Alternatively, these tokens can be used for lexical extraction, which can be performed by the ErrorBuilder typeclass: this can be used to try and extract tokens from the input stream when an error happens, to provide a more informative error. In this case, it is desirable to not consume whitespace after the token to keep the error tight and precise.

Source
Lexer.scala
Since

4.0.0

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  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
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  4. final def asInstanceOf[T0]: T0
    Definition Classes
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  5. def clone(): AnyRef
    Attributes
    protected[lang]
    Definition Classes
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    @throws( ... ) @native()
  6. final def eq(arg0: AnyRef): Boolean
    Definition Classes
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  7. def equals(arg0: Any): Boolean
    Definition Classes
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  8. def finalize(): Unit
    Attributes
    protected[lang]
    Definition Classes
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    Annotations
    @throws( classOf[java.lang.Throwable] )
  9. final def getClass(): Class[_]
    Definition Classes
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    @native()
  10. def hashCode(): Int
    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  11. final def isInstanceOf[T0]: Boolean
    Definition Classes
    Any
  12. val names: Names

    This object contains lexing functionality relevant to the parsing of names, which include operators or identifiers.

    This object contains lexing functionality relevant to the parsing of names, which include operators or identifiers.

    The parsing of names is mostly concerned with finding the longest valid name that is not a reserved name, such as a hard keyword or a special operator.

    Since

    4.0.0

  13. final def ne(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  14. final def notify(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native()
  15. final def notifyAll(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native()
  16. val symbol: Symbol

    This object contains lexing functionality relevant to the parsing of atomic symbols.

    This object contains lexing functionality relevant to the parsing of atomic symbols.

    Symbols are characterised by their "unitness", that is, every parser inside returns Unit. This is because they all parse a specific known entity, and, as such, the result of the parse is irrelevant. These can be things such as reserved names, or small symbols like parentheses. This object also contains a means of creating new symbols as well as implicit conversions to allow for Scala's string literals to serve as symbols within a parser.

    Since

    4.0.0

  17. final def synchronized[T0](arg0: ⇒ T0): T0
    Definition Classes
    AnyRef
  18. def toString(): String
    Definition Classes
    AnyRef → Any
  19. final def wait(): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  20. final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  21. final def wait(arg0: Long): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... ) @native()
  22. object numeric

    This object contains lexing functionality relevant to the parsing of numbers.

    This object contains lexing functionality relevant to the parsing of numbers. This is sub-divided into different categories:

    • integers (both signed and unsigned)
    • reals (signed only)
    • a combination of the two (signed and unsigned)

    These contain relevant functionality for the processing of decimal, hexadecimal, octal, and binary literals; or some mixed combination thereof (as specified by desc.numericDesc). Additionally, it is possible to ensure literals represent known sizes or precisions.

    Since

    4.0.0

  23. object text

    This object contains lexing functionality relevant to the parsing of text.

    This object contains lexing functionality relevant to the parsing of text. This is sub-divided into different categories:

    • string literals (both with escapes and raw)
    • multi-line string literals (both with escapes and raw)
    • character literals

    These contain the relevant functionality required to specify the degree of unicode support for the underlying language, from ASCII to full UTF-16.

    Since

    4.0.0

Inherited from AnyRef

Inherited from Any

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