scala.util.parsing.combinator

Parsers

trait Parsers extends AnyRef

Parsers is a component that provides generic parser combinators.

It requires the type of the elements these parsers should parse (each parser is polymorphic in the type of result it produces).

There are two aspects to the result of a parser: (1) success or failure, and (2) the result. A Parser[T] provides both kinds of information.

The term parser combinator refers to the fact that these parsers are constructed from primitive parsers and composition operators, such as sequencing, alternation, optionality, repetition, lifting, and so on.

A primitive parser is a parser that accepts or rejects a single piece of input, based on a certain criterion, such as whether the input...

Even more primitive parsers always produce the same result, irrespective of the input.

linear super types: AnyRef, Any
known subclasses: RegexParsers, RegexTest, TokenParsers, StdTokenParsers, StandardTokenParsers, Scanners, Lexical, StdLexical, JavaTokenParsers, PackratParsers, Parser, JSON, Lexer
source: Parsers.scala
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Type Members

  1. type Elem

    the type of input elements the provided parsers consume (When consuming invidual characters, a parser is typically called a scanner, which produces tokens that are consumed by what is normally called a parser. Nonetheless, the same principles apply, regardless of the input type.)

    the type of input elements the provided parsers consume (When consuming invidual characters, a parser is typically called a scanner, which produces tokens that are consumed by what is normally called a parser. Nonetheless, the same principles apply, regardless of the input type.)

    attributes: abstract
  2. class Error (msg: String, next: Input) extends NoSuccess with Product

    The fatal failure case of ParseResult: contains an error-message and the remaining input.

  3. class Failure (msg: String, next: Input) extends NoSuccess with Product

    The failure case of ParseResult: contains an error-message and the remaining input.

  4. type Input = Reader[Elem]

    The parser input is an abstract reader of input elements, i.

    The parser input is an abstract reader of input elements, i.e. the type of input the parsers in this component expect.

  5. class NoSuccess extends ParseResult[Nothing]

    A common super-class for unsuccessful parse results

  6. trait OnceParser [+T] extends Parser[T]

    A parser whose ~ combinator disallows back-tracking.

  7. class ParseResult [+T] extends AnyRef

    A base class for parser results.

  8. class Parser [+T] extends (Input) ⇒ ParseResult[T]

    The root class of parsers.

  9. class Success [+T] (result: T, next: Input) extends ParseResult[T] with Product

    The success case of ParseResult: contains the result and the remaining input.

  10. class ~ [+a, +b] (_1: a, _2: b) extends Product

Value Members

  1. def != (arg0: AnyRef) : Boolean

    attributes: final
    definition classes: AnyRef
  2. def != (arg0: Any) : Boolean

    o != arg0 is the same as !(o == (arg0)).

    o != arg0 is the same as !(o == (arg0)).

    arg0

    the object to compare against this object for dis-equality.

    returns

    false if the receiver object is equivalent to the argument; true otherwise.

    attributes: final
    definition classes: Any
  3. def ## () : Int

    attributes: final
    definition classes: AnyRef → Any
  4. def $asInstanceOf [T0] () : T0

    attributes: final
    definition classes: AnyRef
  5. def $isInstanceOf [T0] () : Boolean

    attributes: final
    definition classes: AnyRef
  6. def == (arg0: AnyRef) : Boolean

    o == arg0 is the same as if (o eq null) arg0 eq null else o.equals(arg0).

    o == arg0 is the same as if (o eq null) arg0 eq null else o.equals(arg0).

    arg0

    the object to compare against this object for equality.

    returns

    true if the receiver object is equivalent to the argument; false otherwise.

    attributes: final
    definition classes: AnyRef
  7. def == (arg0: Any) : Boolean

    o == arg0 is the same as o.equals(arg0).

    o == arg0 is the same as o.equals(arg0).

    arg0

    the object to compare against this object for equality.

    returns

    true if the receiver object is equivalent to the argument; false otherwise.

    attributes: final
    definition classes: Any
  8. object NoSuccess extends AnyRef

    An extractor so NoSuccess(msg, next) can be used in matches.

  9. def OnceParser [T] (f: (Input) ⇒ ParseResult[T]) : Parser[T] with OnceParser[T]

  10. def Parser [T] (f: (Input) ⇒ ParseResult[T]) : Parser[T]

  11. def accept [U] (expected: String, f: PartialFunction[Elem, U]) : Parser[U]

    The parser that matches an element in the domain of the partial function f' If f' is defined on the first element in the input, f' is applied to it to produce this parser's result. Example: The parser <code>accept("name", {case Identifier(n) => Name(n)})</code> accepts an <code>Identifier(n)</code> and returns a <code>Name(n)</code>.

    The parser that matches an element in the domain of the partial function f' If f' is defined on the first element in the input, f' is applied to it to produce this parser's result. Example: The parser <code>accept("name", {case Identifier(n) => Name(n)})</code> accepts an <code>Identifier(n)</code> and returns a <code>Name(n)</code>.

    expected

    a description of the kind of element this parser expects (for error messages)

    f

    a partial function that determines when this parser is successful and what its output is

    returns

    A parser that succeeds if f' is applicable to the first element of the input, applying f' to it to produce the result.

  12. def accept [ES] (es: ES)(implicit arg0: (ES) ⇒ List[Elem]) : Parser[List[Elem]]

    A parser that matches only the given list of element es' accept(es) succeeds if the input subsequently provides the elements in the list es'.

    A parser that matches only the given list of element es' accept(es) succeeds if the input subsequently provides the elements in the list es'.

    es

    the list of expected elements

    returns

    a Parser that recognizes a specified list of elements

  13. implicit def accept (e: Elem) : Parser[Elem]

    A parser that matches only the given element e' The method is implicit so that elements can automatically be lifted to their parsers. For example, when parsing Token's, Identifier("new") (which is a Token') can be used directly, instead of first creating a Parser' using accept(Identifier("new")).

    A parser that matches only the given element e' The method is implicit so that elements can automatically be lifted to their parsers. For example, when parsing Token's, Identifier("new") (which is a Token') can be used directly, instead of first creating a Parser' using accept(Identifier("new")).

    e

    the Elem' that must be the next piece of input for the returned parser to succeed

    returns

    a tParser' that succeeds if e' is the next available input.

    attributes: implicit
  14. def acceptIf (p: (Elem) ⇒ Boolean)(err: (Elem) ⇒ String) : Parser[Elem]

  15. def acceptMatch [U] (expected: String, f: PartialFunction[Elem, U]) : Parser[U]

  16. def acceptSeq [ES] (es: ES)(implicit arg0: (ES) ⇒ Iterable[Elem]) : Parser[List[Elem]]

  17. def asInstanceOf [T0] : T0

    This method is used to cast the receiver object to be of type T0.

    This method is used to cast the receiver object to be of type T0.

    Note that the success of a cast at runtime is modulo Scala's erasure semantics. Therefore the expression1.asInstanceOf[String] will throw a ClassCastException at runtime, while the expressionList(1).asInstanceOf[List[String]] will not. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the requested typed.

    returns

    the receiver object.

    attributes: final
    definition classes: Any
  18. def chainl1 [T, U] (first: ⇒ Parser[T], p: ⇒ Parser[U], q: ⇒ Parser[(T, U) ⇒ T]) : Parser[T]

    A parser generator that, roughly, generalises the rep1sep generator so that q', which parses the separator, produces a left-associative function that combines the elements it separates.

    A parser generator that, roughly, generalises the rep1sep generator so that q', which parses the separator, produces a left-associative function that combines the elements it separates.

    first

    a parser that parses the first element

    p

    a parser that parses the subsequent elements

    q

    a parser that parses the token(s) separating the elements, yielding a left-associative function that combines two elements into one

  19. def chainl1 [T] (p: ⇒ Parser[T], q: ⇒ Parser[(T, T) ⇒ T]) : Parser[T]

    A parser generator that, roughly, generalises the rep1sep generator so that q', which parses the separator, produces a left-associative function that combines the elements it separates. From: J. Fokker. Functional parsers. In J. Jeuring and E. Meijer, editors, Advanced Functional Programming, volume 925 of Lecture Notes in Computer Science, pages 1--23. Springer, 1995.

    A parser generator that, roughly, generalises the rep1sep generator so that q', which parses the separator, produces a left-associative function that combines the elements it separates. From: J. Fokker. Functional parsers. In J. Jeuring and E. Meijer, editors, Advanced Functional Programming, volume 925 of Lecture Notes in Computer Science, pages 1--23. Springer, 1995.

    p

    a parser that parses the elements

    q

    a parser that parses the token(s) separating the elements, yielding a left-associative function that combines two elements into one

  20. def chainr1 [T, U] (p: ⇒ Parser[T], q: ⇒ Parser[(T, U) ⇒ U], combine: (T, U) ⇒ U, first: U) : Parser[U]

    A parser generator that generalises the rep1sep generator so that q', which parses the separator, produces a right-associative function that combines the elements it separates. Additionally, The right-most (last) element and the left-most combining function have to be supplied. rep1sep(p: Parser[T], q) corresponds to chainr1(p, q ^^ cons, cons, Nil) (where val cons = (x: T, y: List[T]) => x :: y)

    A parser generator that generalises the rep1sep generator so that q', which parses the separator, produces a right-associative function that combines the elements it separates. Additionally, The right-most (last) element and the left-most combining function have to be supplied. rep1sep(p: Parser[T], q) corresponds to chainr1(p, q ^^ cons, cons, Nil) (where val cons = (x: T, y: List[T]) => x :: y)

    p

    a parser that parses the elements

    q

    a parser that parses the token(s) separating the elements, yielding a right-associative function that combines two elements into one

    combine

    the "last" (left-most) combination function to be applied

    first

    the "first" (right-most) element to be combined

  21. def clone () : AnyRef

    This method creates and returns a copy of the receiver object.

    This method creates and returns a copy of the receiver object.

    The default implementation of the clone method is platform dependent.

    returns

    a copy of the receiver object.

    attributes: protected
    definition classes: AnyRef
  22. def commit [T] (p: ⇒ Parser[T]) : Parser[T]

    Wrap a parser so that its failures become errors (the | combinator will give up as soon as it encounters an error, on failure it simply tries the next alternative)

    Wrap a parser so that its failures become errors (the | combinator will give up as soon as it encounters an error, on failure it simply tries the next alternative)

  23. def elem (e: Elem) : Parser[Elem]

    A parser that matches only the given element e' elem(e) succeeds if the input starts with an element e'

    A parser that matches only the given element e' elem(e) succeeds if the input starts with an element e'

    e

    the Elem' that must be the next piece of input for the returned parser to succeed

    returns

    a Parser' that succeeds if e' is the next available input (and returns it).

  24. def elem (kind: String, p: (Elem) ⇒ Boolean) : Parser[Elem]

    A parser matching input elements that satisfy a given predicate

    A parser matching input elements that satisfy a given predicate

    elem(kind, p) succeeds if the input starts with an element e' for which p(e) is true.

    kind

    The element kind, used for error messages

    p

    A predicate that determines which elements match. @return

  25. def eq (arg0: AnyRef) : Boolean

    This method is used to test whether the argument (arg0) is a reference to the receiver object (this).

    This method is used to test whether the argument (arg0) is a reference to the receiver object (this).

    The eq method implements an [http://en.wikipedia.org/wiki/Equivalence_relation equivalence relation] on non-null instances of AnyRef: * It is reflexive: for any non-null instance x of type AnyRef, x.eq(x) returns true. * It is symmetric: for any non-null instances x and y of type AnyRef, x.eq(y) returns true if and only if y.eq(x) returns true. * It is transitive: for any non-null instances x, y, and z of type AnyRef if x.eq(y) returns true and y.eq(z) returns true, then x.eq(z) returns true.

    Additionally, the eq method has three other properties. * It is consistent: for any non-null instances x and y of type AnyRef, multiple invocations of x.eq(y) consistently returns true or consistently returns false. * For any non-null instance x of type AnyRef, x.eq(null) and null.eq(x) returns false. * null.eq(null) returns true.

    When overriding the equals or hashCode methods, it is important to ensure that their behavior is consistent with reference equality. Therefore, if two objects are references to each other (o1 eq o2), they should be equal to each other (o1 == o2) and they should hash to the same value (o1.hashCode == o2.hashCode).

    arg0

    the object to compare against this object for reference equality.

    returns

    true if the argument is a reference to the receiver object; false otherwise.

    attributes: final
    definition classes: AnyRef
  26. def equals (arg0: Any) : Boolean

    This method is used to compare the receiver object (this) with the argument object (arg0) for equivalence.

    This method is used to compare the receiver object (this) with the argument object (arg0) for equivalence.

    The default implementations of this method is an [http://en.wikipedia.org/wiki/Equivalence_relation equivalence relation]: * It is reflexive: for any instance x of type Any, x.equals(x) should return true. * It is symmetric: for any instances x and y of type Any, x.equals(y) should return true if and only if y.equals(x) returns true. * It is transitive: for any instances x, y, and z of type AnyRef if x.equals(y) returns true and y.equals(z) returns true, then x.equals(z) should return true.

    If you override this method, you should verify that your implementation remains an equivalence relation. Additionally, when overriding this method it is often necessary to override hashCode to ensure that objects that are "equal" (o1.equals(o2) returns true) hash to the same scala.Int (o1.hashCode.equals(o2.hashCode)).

    arg0

    the object to compare against this object for equality.

    returns

    true if the receiver object is equivalent to the argument; false otherwise.

    definition classes: AnyRef → Any
  27. def err (msg: String) : Parser[Nothing]

    A parser that results in an error

    A parser that results in an error

    msg

    The error message describing the failure.

    returns

    A parser that always fails with the specified error message.

  28. def failure (msg: String) : Parser[Nothing]

    A parser that always fails

    A parser that always fails

    msg

    The error message describing the failure.

    returns

    A parser that always fails with the specified error message.

  29. def finalize () : Unit

    This method is called by the garbage collector on the receiver object when garbage collection determines that there are no more references to the object.

    This method is called by the garbage collector on the receiver object when garbage collection determines that there are no more references to the object.

    The details of when and if the finalize method are invoked, as well as the interaction between finalizeand non-local returns and exceptions, are all platform dependent.

    attributes: protected
    definition classes: AnyRef
  30. def getClass () : java.lang.Class[_]

    Returns a representation that corresponds to the dynamic class of the receiver object.

    Returns a representation that corresponds to the dynamic class of the receiver object.

    The nature of the representation is platform dependent.

    returns

    a representation that corresponds to the dynamic class of the receiver object.

    attributes: final
    definition classes: AnyRef
  31. def guard [T] (p: ⇒ Parser[T]) : Parser[T]

    A parser generator for guard expressions.

    A parser generator for guard expressions. The resulting parser will fail or succeed just like the one given as parameter but it will not consume any input.

    p

    a Parser' that is to be applied to the input

    returns

    A parser that returns success if and only if 'p' succeeds but never consumes any input

  32. def hashCode () : Int

    Returns a hash code value for the object.

    Returns a hash code value for the object.

    The default hashing algorithm is platform dependent.

    Note that it is allowed for two objects to have identical hash codes (o1.hashCode.equals(o2.hashCode)) yet not be equal (o1.equals(o2) returns false). A degenerate implementation could always return 0. However, it is required that if two objects are equal (o1.equals(o2) returns true) that they have identical hash codes (o1.hashCode.equals(o2.hashCode)). Therefore, when overriding this method, be sure to verify that the behavior is consistent with the equals method.

    returns

    the hash code value for the object.

    definition classes: AnyRef → Any
  33. def isInstanceOf [T0] : Boolean

    This method is used to test whether the dynamic type of the receiver object is T0.

    This method is used to test whether the dynamic type of the receiver object is T0.

    Note that the test result of the test is modulo Scala's erasure semantics. Therefore the expression1.isInstanceOf[String] will return false, while the expression List(1).isInstanceOf[List[String]] will return true. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the requested typed.

    returns

    true if the receiver object is an instance of erasure of type T0; false otherwise.

    attributes: final
    definition classes: Any
  34. var lastNoSuccess : NoSuccess

  35. def log [T] (p: ⇒ Parser[T])(name: String) : Parser[T]

  36. def mkList [T] : (~[T, List[T]]) ⇒ List[T]

  37. def ne (arg0: AnyRef) : Boolean

    o.ne(arg0) is the same as !(o.eq(arg0)).

    o.ne(arg0) is the same as !(o.eq(arg0)).

    arg0

    the object to compare against this object for reference dis-equality.

    returns

    false if the argument is not a reference to the receiver object; true otherwise.

    attributes: final
    definition classes: AnyRef
  38. def not [T] (p: ⇒ Parser[T]) : Parser[Unit]

    Wrap a parser so that its failures&errors become success and vice versa -- it never consumes any input

    Wrap a parser so that its failures&errors become success and vice versa -- it never consumes any input

  39. def notify () : Unit

    Wakes up a single thread that is waiting on the receiver object's monitor.

    Wakes up a single thread that is waiting on the receiver object's monitor.

    attributes: final
    definition classes: AnyRef
  40. def notifyAll () : Unit

    Wakes up all threads that are waiting on the receiver object's monitor.

    Wakes up all threads that are waiting on the receiver object's monitor.

    attributes: final
    definition classes: AnyRef
  41. def opt [T] (p: ⇒ Parser[T]) : Parser[Option[T]]

    A parser generator for optional sub-phrases.

    A parser generator for optional sub-phrases.

    opt(p) is a parser that returns Some(x)' if p' returns x' and None' if p' fails

    p

    A Parser' that is tried on the input

    returns

    a Parser' that always succeeds: either with the result provided by p' or with the empty result

  42. def phrase [T] (p: Parser[T]) : Parser[T]

    A parser generator delimiting whole phrases (i.

    A parser generator delimiting whole phrases (i.e. programs).

    phrase(p) succeeds if p succeeds and no input is left over after p.

    p

    the parser that must consume all input for the resulting parser to succeed.

    returns

    a parser that has the same result as p', but that only succeeds if <code>p</code> consumed all the input.

  43. def positioned [T <: Positional] (p: ⇒ Parser[T]) : Parser[T]

    positioned' decorates a parser's result with the start position of the input it consumed.

    positioned' decorates a parser's result with the start position of the input it consumed.

    p

    a Parser' whose result conforms to Positional'.

    returns

    A parser that has the same behaviour as p', but which marks its result with the start position of the input it consumed, if it didn't already have a position.

  44. def rep [T] (p: ⇒ Parser[T]) : Parser[List[T]]

    A parser generator for repetitions.

    A parser generator for repetitions.

    rep(p) repeatedly uses p' to parse the input until p' fails (the result is a List of the consecutive results of p')

    p

    a Parser' that is to be applied successively to the input

    returns

    A parser that returns a list of results produced by repeatedly applying p' to the input.

  45. def rep1 [T] (first: ⇒ Parser[T], p: ⇒ Parser[T]) : Parser[List[T]]

    A parser generator for non-empty repetitions.

    A parser generator for non-empty repetitions.

    rep1(f, p) first uses f' (which must succeed) and then repeatedly uses p' to parse the input until p' fails (the result is a List' of the consecutive results of f' and p')

    first

    a Parser' that parses the first piece of input

    p

    a Parser' that is to be applied successively to the rest of the input (if any)

    returns

    A parser that returns a list of results produced by first applying f' and then repeatedly p' to the input (it only succeeds if f' matches).

  46. def rep1 [T] (p: ⇒ Parser[T]) : Parser[List[T]]

    A parser generator for non-empty repetitions.

    A parser generator for non-empty repetitions.

    rep1(p) repeatedly uses p' to parse the input until p' fails -- p' must succeed at least once (the result is a List' of the consecutive results of p')

    p

    a Parser' that is to be applied successively to the input

    returns

    A parser that returns a list of results produced by repeatedly applying p' to the input (and that only succeeds if p' matches at least once).

  47. def rep1sep [T] (p: ⇒ Parser[T], q: ⇒ Parser[Any]) : Parser[List[T]]

    A parser generator for non-empty repetitions.

    A parser generator for non-empty repetitions.

    rep1sep(p, q) repeatedly applies p' interleaved with q' to parse the input, until p' fails. The parser p' must succeed at least once.

    p

    a Parser' that is to be applied successively to the input

    q

    a Parser' that parses the elements that separate the elements parsed by p' (interleaved with q')

    returns

    A parser that returns a list of results produced by repeatedly applying p' to the input (and that only succeeds if p' matches at least once). The results of p' are collected in a list. The results of q' are discarded.

  48. def repN [T] (num: Int, p: ⇒ Parser[T]) : Parser[List[T]]

    A parser generator for a specified number of repetitions.

    A parser generator for a specified number of repetitions.

    repN(n, p) uses p' exactly n' time to parse the input (the result is a List' of the n' consecutive results of p')

    p

    a Parser' that is to be applied successively to the input

    returns

    A parser that returns a list of results produced by repeatedly applying p' to the input (and that only succeeds if p' matches exactly n' times).

  49. def repsep [T] (p: ⇒ Parser[T], q: ⇒ Parser[Any]) : Parser[List[T]]

    A parser generator for interleaved repetitions.

    A parser generator for interleaved repetitions.

    repsep(p, q) repeatedly uses p' interleaved with q' to parse the input, until p' fails. (The result is a List' of the results of p'.) Example: <code>repsep(term, ",")</code> parses a comma-separated list of term's, yielding a list of these terms

    p

    a Parser' that is to be applied successively to the input

    q

    a Parser' that parses the elements that separate the elements parsed by p'

    returns

    A parser that returns a list of results produced by repeatedly applying p' (interleaved with q') to the input. The results of p' are collected in a list. The results of q' are discarded.

  50. def success [T] (v: T) : Parser[T]

    A parser that always succeeds

    A parser that always succeeds

    v

    The result for the parser

    returns

    A parser that always succeeds, with the given result v'

  51. def synchronized [T0] (arg0: T0) : T0

    attributes: final
    definition classes: AnyRef
  52. def toString () : String

    Returns a string representation of the object.

    Returns a string representation of the object.

    The default representation is platform dependent.

    returns

    a string representation of the object.

    definition classes: AnyRef → Any
  53. def wait () : Unit

    attributes: final
    definition classes: AnyRef
  54. def wait (arg0: Long, arg1: Int) : Unit

    attributes: final
    definition classes: AnyRef
  55. def wait (arg0: Long) : Unit

    attributes: final
    definition classes: AnyRef

Inherited from AnyRef

Inherited from Any