/**
* Returns a parser that produces the given stream of characters or fails otherwise.
*
* @param missing The error if the producing stream could not supply more characters.
* @param sat The error if a character was produced that is not the given stream of characters.
* @param cs The stream of characters to produce.
* @return A parser that produces the given stream of characters or fails otherwise.
*/
public static <E> Parser<Stream<Character>, Stream<Character>, E> characters(
final F0<E> missing, final F<Character, E> sat, final Stream<Character> cs) {
return cs.isEmpty()
? Parser.<Stream<Character>, Stream<Character>, E>value(Stream.<Character>nil())
: character(missing, sat, cs.head())
.bind(characters(missing, sat, cs.tail()._1()), Stream.<Character>cons_());
}
/**
* Returns a parser that produces an element from the stream that satisfies the given predicate,
* or fails.
*
* @param missing The error if no element is available.
* @param sat The error if the element does not satisfy the predicate.
* @param f The predicate that the element should satisfy.
* @return A parser that produces an element from the stream that satisfies the given predicate,
* or fails.
*/
public static <I, E> Parser<Stream<I>, I, E> satisfy(
final F0<E> missing, final F<I, E> sat, final F<I, Boolean> f) {
return StreamParser.<I, E>element(missing)
.bind(
x ->
f.f(x)
? Parser.<Stream<I>, I, E>value(x)
: Parser.<Stream<I>, I, E>fail(sat.f(x)));
}
/**
* Returns a parser that produces the given number of characters, or fails with the given error.
*
* @param missing The error if the given number of characters is unavailable.
* @param n The number of characters to produce in the parse result.
* @return A parser that produces the given number of characters, or fails with the given error.
*/
public static <E> Parser<Stream<Character>, Stream<Character>, E> characters(
final F0<E> missing, final int n) {
return n <= 0
? Parser.<Stream<Character>, Stream<Character>, E>value(Stream.<Character>nil())
: character(missing).bind(characters(missing, n - 1), Stream.<Character>cons_());
}
/**
* Sequence the list of parsers through {@link #bind}.
*
* @param ps The parsers to sequence.
* @return A parser after sequencing.
*/
public static <I, A, E> Parser<I, List<A>, E> sequence(final List<Parser<I, A, E>> ps) {
return ps.isEmpty()
? Parser.<I, List<A>, E>value(List.<A>nil())
: ps.head().bind(a -> sequence(ps.tail()).map(cons_(a)));
}
