Packages

  • package root

    This is the documentation for Parsley.

    This is the documentation for Parsley.

    Package structure

    The parsley package contains the Parsley class, as well as the Result, Success, and Failure types. In addition to these, it also contains the following packages and "modules" (a module is defined as being an object which mocks a package):

    • parsley.Parsley contains the bulk of the core "function-style" combinators.
    • parsley.combinator contains many helpful combinators that simplify some common parser patterns.
    • parsley.character contains the combinators needed to read characters and strings, as well as combinators to match specific sub-sets of characters.
    • parsley.debug contains debugging combinators, helpful for identifying faults in parsers.
    • parsley.expr contains the following sub modules:
      • parsley.expr.chain contains combinators used in expression parsing
      • parsley.expr.precedence is a builder for expression parsers built on a precedence table.
      • parsley.expr.infix contains combinators used in expression parsing, but with more permissive types than their equivalents in chain.
      • parsley.expr.mixed contains combinators that can be used for expression parsing, but where different fixities may be mixed on the same level: this is rare in practice.
    • parsley.syntax contains several implicits to add syntactic sugar to the combinators. These are sub-categorised into the following sub modules:
      • parsley.syntax.character contains implicits to allow you to use character and string literals as parsers.
      • parsley.syntax.lift enables postfix application of the lift combinator onto a function (or value).
      • parsley.syntax.zipped enables boths a reversed form of lift where the function appears on the right and is applied on a tuple (useful when type inference has failed) as well as a .zipped method for building tuples out of several combinators.
      • parsley.syntax.extension contains syntactic sugar combinators exposed as implicit classes.
    • parsley.errors contains modules to deal with error messages, their refinement and generation.
    • parsley.lift contains functions which lift functions that work on regular types to those which now combine the results of parsers returning those same types. these are ubiquitous.
    • parsley.ap contains functions which allow for the application of a parser returning a function to several parsers returning each of the argument types.
    • parsley.state contains combinators that interact with the context-sensitive functionality in the form of state.
    • parsley.token contains the Lexer class that provides a host of helpful lexing combinators when provided with the description of a language.
    • parsley.position contains parsers for extracting position information.
    • parsley.generic contains some basic implementations of the Parser Bridge pattern (see Design Patterns for Parser Combinators in Scala, or the parsley wiki): these can be used before more specialised generic bridge traits can be constructed.
    Definition Classes
    root
  • package parsley
    Definition Classes
    root
  • package expr

    This package contains various functionality relating to the parsing of expressions..

    This package contains various functionality relating to the parsing of expressions..

    This includes the "chain" combinators, which tackle the left-recursion problem and allow for the parsing and combining of operators with values. It also includes functionality for constructing larger precedence tables, which may even vary the type of each layer in the table, allowing for strongly-typed expression parsing.

    Definition Classes
    parsley
  • Atoms
  • Fixity
  • GOps
  • InfixL
  • InfixN
  • InfixR
  • Ops
  • Postfix
  • Prec
  • Prefix
  • SOps
  • chain
  • infix
  • mixed
  • precedence

object chain

This module contains the very useful chaining family of combinators, which are mostly used to parse operators and expressions of varying fixities. It is a more low-level API compared with precedence.

Source
chain.scala
Since

2.2.0

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  1. final def !=(arg0: Any): Boolean
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  2. final def ##: Int
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  3. final def ==(arg0: Any): Boolean
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  4. final def asInstanceOf[T0]: T0
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  5. def clone(): AnyRef
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  8. def finalize(): Unit
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  9. final def getClass(): Class[_ <: AnyRef]
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  10. def hashCode(): Int
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  11. final def isInstanceOf[T0]: Boolean
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  12. def left[A](p: Parsley[A])(op: => Parsley[(A, A) => A], x: A): Parsley[A]

    This combinator handles left-associative parsing, and application of, zero or more binary operators between zero or more values.

    This combinator handles left-associative parsing, and application of, zero or more binary operators between zero or more values.

    First parse p, then parse op followed by a p repeatedly. The results of the ps, x1 through xn, are combined with the results of the ops, f1 through fn-1, with left-associative application: fn-1(fn-2(..f1(x1, x2).., xn-1), xn). This application is then returned as the result of the combinator. If p or op fails having consumed input at any point, the whole combinator fails. If no p could be parsed, this combinator will return a default result x.

    p

    the value to be parsed.

    op

    the operator between each value.

    x

    the default value to return if no ps can be parsed.

    returns

    a parser that parses alternating p and op, ending in a p and applies their results left-associatively or returns x if no p was parsed.

    Example:

    1. scala> import parsley.expr.chain
scala> import parsley.character.{digit, char}
scala> sealed trait Expr
scala> case class Add(x: Expr, y: Expr) extends Expr
scala> case class Num(x: Int) extends Expr
scala> val expr = chain.left(digit.map(d => Num(d.asDigit)))(char('+').as(Add), Num(0))
scala> expr.parse("1+2+3+4")
val res0 = Success(Add(Add(Add(Num(1), Num(2)), Num(3)), Num(4)))
scala> expr.parse("")
val res1 = Success(Num(0))
    Since

    4.0.0

    See also

    infix.left for a version where the types can vary, ensuring that the associativity is enforced in a type-safe way.

  13. def left1[A](p: Parsley[A])(op: => Parsley[(A, A) => A]): Parsley[A]

    This combinator handles left-associative parsing, and application of, zero or more binary operators between one or more values.

    This combinator handles left-associative parsing, and application of, zero or more binary operators between one or more values.

    First parse p, then parse op followed by a p repeatedly. The results of the ps, x1 through xn, are combined with the results of the ops, f1 through fn-1, with left-associative application: fn-1(fn-2(..f1(x1, x2).., xn-1), xn). This application is then returned as the result of the combinator. If p or op fails having consumed input at any point, the whole combinator fails.

    p

    the value to be parsed.

    op

    the operator between each value.

    returns

    a parser that parses alternating p and op, ending in a p and applies their results left-associatively.

    Example:

    1. scala> import parsley.expr.chain
scala> import parsley.character.{digit, char}
scala> sealed trait Expr
scala> case class Add(x: Expr, y: Expr) extends Expr
scala> case class Num(x: Int) extends Expr
scala> val expr = chain.left1(digit.map(d => Num(d.asDigit)))(char('+').as(Add))
scala> expr.parse("1+2+3+4")
val res0 = Success(Add(Add(Add(Num(1), Num(2)), Num(3)), Num(4)))
scala> expr.parse("")
val res1 = Failure(..)
    Since

    4.0.0

    See also

    infix.left1 for a version where the types can vary, ensuring that the associativity is enforced in a type-safe way.

  14. final def ne(arg0: AnyRef): Boolean
    Definition Classes
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  15. final def notify(): Unit
    Definition Classes
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    @native()
  16. final def notifyAll(): Unit
    Definition Classes
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  17. def postfix[A](p: Parsley[A])(op: => Parsley[(A) => A]): Parsley[A]

    This combinator handles left-assocative parsing, and application of, zero or more postfix unary operators to a single value.

    This combinator handles left-assocative parsing, and application of, zero or more postfix unary operators to a single value.

    First parse a single p. Then, parse many repeated ops. The result of p, x, is applied to each of the results of the ops, f1 through fn, such that f1 is applied first and fn last: fn(fn-1(..f1(x)..)). This application is then returned as the result of the combinator. If p or op fails having consumed input at any point, the whole combinator fails.

    p

    the single value to be parsed.

    op

    the postfix operator to repeatedly parser after p.

    returns

    a parser that an initial p, then many ops, and applies all of the results left-associatively.

    Example:

    1. scala> import parsley.expr.chain
scala> import parsley.character.{digit, string}
scala> sealed trait Expr
scala> case class Inc(x: Expr) extends Expr
scala> case class Dec(x: Expr) extends Expr
scala> case class Num(x: Int) extends Expr
scala> val expr = chain.postfix(digit.map(d => Num(d.asDigit)))(string("++").as(Inc) <|> string("--").as(Dec))
scala> expr.parse("1++----")
val res0 = Success(Dec(Dec(Inc(Num(1)))))
scala> expr.parse("1")
val res1 = Success(Num(1))
scala> expr.parse("")
val res2 = Failure(..)
    Since

    2.2.0

  18. def postfix1[A, B <: A](p: Parsley[A])(op: => Parsley[(A) => B]): Parsley[B]

    This combinator handles left-assocative parsing, and application of, one or more postfix unary operators to a single value.

    This combinator handles left-assocative parsing, and application of, one or more postfix unary operators to a single value.

    First parse a single p. Then, parse at least one repeated ops. The result of p, x, is applied to each of the results of the ops, f1 through fn, such that f1 is applied first and fn last: fn(fn-1(..f1(x)..)). This application is then returned as the result of the combinator. If p or op fails having consumed input at any point, the whole combinator fails.

    p

    the single value to be parsed.

    op

    the postfix operator to repeatedly parser after p.

    returns

    a parser that an initial p, then some ops, and applies all of the results left-associatively.

    Example:

    1. scala> import parsley.expr.chain
scala> import parsley.character.{digit, string}
scala> sealed trait Expr
scala> case class Inc(x: Expr) extends Expr
scala> case class Dec(x: Expr) extends Expr
scala> case class Num(x: Int) extends Expr
scala> val expr = chain.postfix1(digit.map(d => Num(d.asDigit)), string("++").as(Inc) <|> string("--").as(Dec))
scala> expr.parse("1++----")
val res0 = Success(Dec(Dec(Inc(Num(1)))))
scala> expr.parse("1")
val res1 = Failure(..)
scala> expr.parse("")
val res2 = Failure(..)
    Since

    3.0.0

  19. def prefix[A](p: Parsley[A])(op: Parsley[(A) => A]): Parsley[A]

    This combinator handles right-assocative parsing, and application of, zero or more prefix unary operators to a single value.

    This combinator handles right-assocative parsing, and application of, zero or more prefix unary operators to a single value.

    First parse many repeated ops. When there are no more ops left to parse, parse a single p. The result of p, x, is applied to each of the results of the ops, f1 through fn, such that fn is applied first and f1 last: f1(f2(..fn(x)..)). This application is then returned as the result of the combinator. If p or op fails having consumed input at any point, the whole combinator fails.

    p

    the single value to be parsed.

    op

    the prefix operator to repeatedly parse before p.

    returns

    a parser that parses many ops, and a final p, and applies all of the results right-associatively.

    Example:

    1. scala> import parsley.expr.chain
scala> import parsley.character.{digit, char}
scala> sealed trait Expr
scala> case class Negate(x: Expr) extends Expr
scala> case class Id(x: Expr) extends Expr
scala> case class Num(x: Int) extends Expr
scala> val expr = chain.prefix(digit.map(d => Num(d.asDigit))(char('-').as(Negate) <|> char('+').as(Id))
scala> expr.parse("--+1")
val res0 = Success(Negate(Negate(Id(Num(1)))))
scala> expr.parse("1")
val res1 = Success(Num(1))
scala> expr.parse("")
val res2 = Failure(..)
    Since

    2.2.0

  20. def prefix1[A, B <: A](p: => Parsley[A])(op: Parsley[(A) => B]): Parsley[B]

    This combinator handles right-assocative parsing, and application of, one or more prefix unary operators to a single value.

    This combinator handles right-assocative parsing, and application of, one or more prefix unary operators to a single value.

    First parse at least one repeated ops. When there are no more ops left to parse, parse a single p. The result of p, x, is applied to each of the results of the ops, f1 through fn, such that fn is applied first and f1 last: f1(f2(..fn(x)..)). This application is then returned as the result of the combinator. If p or op fails having consumed input at any point, the whole combinator fails.

    p

    the single value to be parsed.

    op

    the prefix operator to repeatedly parse before p.

    returns

    a parser that parses some ops, and a final p, and applies all of the results right-associatively.

    Example:

    1. scala> import parsley.expr.chain
scala> import parsley.character.{digit, char}
scala> sealed trait Expr
scala> case class Negate(x: Expr) extends Expr
scala> case class Id(x: Expr) extends Expr
scala> case class Num(x: Int) extends Expr
scala> val expr = chain.prefix1(digit.map(d => Num(d.asDigit)))(char('-').as(Negate) <|> char('+').as(Id))
scala> expr.parse("--+1")
val res0 = Success(Negate(Negate(Id(Num(1)))))
scala> expr.parse("1")
val res1 = Failure(..)
scala> expr.parse("")
val res2 = Failure(..)
    Since

    3.0.0

  21. def right[A](p: Parsley[A])(op: => Parsley[(A, A) => A], x: A): Parsley[A]

    This combinator handles right-associative parsing, and application of, zero or more binary operators between zero or more values.

    This combinator handles right-associative parsing, and application of, zero or more binary operators between zero or more values.

    First parse p, then parse op followed by a p repeatedly. The results of the ps, x1 through xn, are combined with the results of the ops, f1 through fn-1, with right-associative application: f1(x1, f2(x2, ..fn-1(xn-1, xn)..)). This application is then returned as the result of the combinator. If p or op fails having consumed input at any point, the whole combinator fails. If no p could be parsed, this combinator will return a default result x.

    p

    the value to be parsed.

    op

    the operator between each value.

    x

    the default value to return if no ps can be parsed.

    returns

    a parser that parses alternating p and op, ending in a p and applies their results right-associatively or returns x if no p was parsed.

    Example:

    1. scala> import parsley.expr.chain
scala> import parsley.character.{digit, char}
scala> sealed trait Expr
scala> case class Add(x: Expr, y: Expr) extends Expr
scala> case class Num(x: Int) extends Expr
scala> val expr = chain.right(digit.map(d => Num(d.asDigit)))(char('+').as(Add), Num(0))
scala> expr.parse("1+2+3+4")
val res0 = Success(Add(Num(1), Add(Num(2), Add(Num(3), Num(4)))))
scala> expr.parse("")
val res1 = Success(Num(0))
    Since

    4.0.0

    See also

    infix.right for a version where the types can vary, ensuring that the associativity is enforced in a type-safe way.

  22. def right1[A](p: Parsley[A])(op: => Parsley[(A, A) => A]): Parsley[A]

    This combinator handles right-associative parsing, and application of, zero or more binary operators between one or more values.

    This combinator handles right-associative parsing, and application of, zero or more binary operators between one or more values.

    First parse p, then parse op followed by a p repeatedly. The results of the ps, x1 through xn, are combined with the results of the ops, f1 through fn-1, with right-associative application: f1(x1, f2(x2, ..fn-1(xn-1, xn)..)). This application is then returned as the result of the combinator. If p or op fails having consumed input at any point, the whole combinator fails.

    p

    the value to be parsed.

    op

    the operator between each value.

    returns

    a parser that parses alternating p and op, ending in a p and applies their results right-associatively.

    Example:

    1. scala> import parsley.expr.chain
scala> import parsley.character.{digit, char}
scala> sealed trait Expr
scala> case class Add(x: Expr, y: Expr) extends Expr
scala> case class Num(x: Int) extends Expr
scala> val expr = chain.right1(digit.map(d => Num(d.asDigit)))(char('+').as(Add))
scala> expr.parse("1+2+3+4")
val res0 = Success(Add(Num(1), Add(Num(2), Add(Num(3), Num(4)))))
scala> expr.parse("")
val res1 = Failure(..)
    Since

    4.0.0

    See also

    infix.right1 for a version where the types can vary, ensuring that the associativity is enforced in a type-safe way.

  23. final def synchronized[T0](arg0: => T0): T0
    Definition Classes
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  24. def toString(): String
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  25. final def wait(): Unit
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  26. final def wait(arg0: Long, arg1: Int): Unit
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  27. final def wait(arg0: Long): Unit
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Inherited from AnyRef

Inherited from Any

Binary Operator Chains

These chains allow for the chaining together of values and binary operators in either left- or right-associative application.

Unary Operator Chains

These chains allow for the chaining together and application of multiple prefix or postfix unary operators to a single value.

Ungrouped