PackratParsers

The root class of packrat parsers.

A specialized Reader class that wraps an underlying Reader and provides memoization of parse results.

The fatal failure case of ParseResult: contains an error-message and the remaining input. No back-tracking is done when a parser returns an Error.

The failure case of ParseResult: contains an error-message and the remaining input. Parsing will back-track when a failure occurs.

A common super-class for unsuccessful parse results.

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

A parser whose ~ combinator disallows back-tracking.

A base class for parser results. A result is either successful or not (failure may be fatal, i.e., an Error, or not, i.e., a Failure). On success, provides a result of type T which consists of some result (and the rest of the input).

The root class of parsers. Parsers are functions from the Input type to ParseResult.

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

A wrapper over sequence of matches.

Given p1: Parser[A] and p2: Parser[B], a parser composed with p1 ~ p2 will have type Parser[~[A, B]]. The successful result of the parser can be extracted from this case class.

It also enables pattern matching, so something like this is possible:

def concat(p1: Parser[String], p2: Parser[String]): Parser[String] =
  p1 ~ p2 ^^ { case a ~ b => a + b }

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

Explicitly convert a given parser to a memoizing packrat parser. In most cases, client code should avoid calling memo directly and rely on implicit conversion instead.

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

Overridden to make sure any input passed to the argument parser is wrapped in a PackratReader.

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 accept("name", {case Identifier(n) => Name(n)}) accepts an Identifier(n) and returns a Name(n)

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 matching input elements that satisfy a given predicate.

acceptIf(p)(el => "Unexpected "+el) succeeds if the input starts with an element e for which p(e) is true.

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 acceptMatch("name", {case Identifier(n) => Name(n)}) accepts an Identifier(n) and returns a Name(n)

A parser that matches only the given scala.collection.Iterable collection of elements es.

acceptSeq(es) succeeds if the input subsequently provides the elements in the iterable es.

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.

''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 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)

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).

A parser that matches only the given element e.

elem(e) succeeds if the input starts with an element e.

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.

A parser that results in an error.

A parser that always fails.

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.

A helper method that turns a Parser into one that will print debugging information to stdout before and after being applied.

Given a concatenation with a repetition (list), move the concatenated element into the list

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

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.

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

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).

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)

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)

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.

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).

A parser generator for a specified range of repetitions interleaved by a separator.

repNM(n, m, p, s) uses p at least n times and up to m times, interleaved with separator s, to parse the input (the result is a List of at least n consecutive results of p and up to m results).

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: repsep(term, ",") parses a comma-separated list of term's, yielding a list of these terms.

A parser that always succeeds.

Implicitly convert a parser to a packrat parser. The conversion is triggered by giving the appropriate target type:

 val myParser: PackratParser[MyResult] = aParser

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 Tokens, Identifier("new") (which is a Token) can be used directly, instead of first creating a Parser using accept(Identifier("new")).