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Functional Java is an open source library that supports closures for the Java programming language
package fj.parser;
import fj.*;
import static fj.P.p;
import static fj.Unit.unit;
import fj.data.List;
import static fj.data.List.cons_;
import fj.data.Stream;
import fj.data.Validation;
import static fj.data.Validation.success;
import static fj.parser.Result.result;
/**
* A parser is a function that takes some input (I) and produces either an error (E) or a parse result (A) and the
* remainder of the input.
*
* @version %build.number%
*/
public final class Parser {
private final F>> f;
private Parser(final F>> f) {
this.f = f;
}
/**
* Parses the input to produce a result or error.
*
* @param i The input to parse.
* @return A parse result with the remaining input or an error.
*/
public Validation> parse(final I i) {
return f.f(i);
}
/**
* Maps the parse input type through an invariant functor.
*
* @param f The function to covariant map.
* @param g The function to contra-variant map.
* @return A parser with the new input type.
*/
public Parser xmap(final F f, final F g) {
return parser(z -> parse(g.f(z)).map(r -> r.mapRest(f)));
}
/**
* Maps the given result type across this parser.
*
* @param f The function to map.
* @return A parser with the new result type.
*/
public Parser map(final F f) {
return parser(i -> parse(i).map(r -> r.mapValue(f)));
}
/**
* Returns a parser that fails with the given error if the result value does not meet the given predicate.
*
* @param f The predicate to filter on.
* @param e The error to in the event that the predicate is not met.
* @return A parser that fails with the given error if the result value does not meet the given predicate.
*/
public Parser filter(final F f, final E e) {
return parser(i -> parse(i).bind(r -> {
final A v = r.value();
return f.f(v) ?
Validation.>success(result(r.rest(), v)) :
Validation.>fail(e);
}));
}
/**
* Binds the given function across the parser with a final join.
*
* @param f The function to apply to the element of this parser.
* @return A new parser after performing the map, then final join.
*/
public Parser bind(final F> f) {
return parser(i -> parse(i).bind(r -> f.f(r.value()).parse(r.rest())));
}
/**
* Binds the given function across the parsers with a final join.
*
* @param f The function to apply to the element of the parsers.
* @param pb A given parser to bind the given function with.
* @return A new parser after performing the map, then final join.
*/
public Parser bind(final Parser pb, final F> f) {
return pb.apply(map(f));
}
/**
* Binds the given function across the parsers with a final join.
*
* @param f The function to apply to the element of the parsers.
* @param pb A given parser to bind the given function with.
* @param pc A given parser to bind the given function with.
* @return A new parser after performing the map, then final join.
*/
public Parser bind(final Parser pb, final Parser pc,
final F>> f) {
return pc.apply(bind(pb, f));
}
/**
* Binds the given function across the parsers with a final join.
*
* @param f The function to apply to the element of the parsers.
* @param pb A given parser to bind the given function with.
* @param pc A given parser to bind the given function with.
* @param pd A given parser to bind the given function with.
* @return A new parser after performing the map, then final join.
*/
public Parser bind(final Parser pb, final Parser pc,
final Parser pd, final F>>> f) {
return pd.apply(bind(pb, pc, f));
}
/**
* Binds the given function across the parsers with a final join.
*
* @param f The function to apply to the element of the parsers.
* @param pb A given parser to bind the given function with.
* @param pc A given parser to bind the given function with.
* @param pd A given parser to bind the given function with.
* @param pe A given parser to bind the given function with.
* @return A new parser after performing the map, then final join.
*/
public Parser bind(final Parser pb, final Parser pc,
final Parser pd, final Parser pe,
final F>>>> f) {
return pe.apply(bind(pb, pc, pd, f));
}
/**
* Binds the given function across the parsers with a final join.
*
* @param f The function to apply to the element of the parsers.
* @param pb A given parser to bind the given function with.
* @param pc A given parser to bind the given function with.
* @param pd A given parser to bind the given function with.
* @param pe A given parser to bind the given function with.
* @param pf A given parser to bind the given function with.
* @return A new parser after performing the map, then final join.
*/
public Parser bind(final Parser pb, final Parser pc,
final Parser pd, final Parser pe,
final Parser pf,
final F>>>>> f) {
return pf.apply(bind(pb, pc, pd, pe, f));
}
/**
* Binds the given function across the parsers with a final join.
*
* @param f The function to apply to the element of the parsers.
* @param pb A given parser to bind the given function with.
* @param pc A given parser to bind the given function with.
* @param pd A given parser to bind the given function with.
* @param pe A given parser to bind the given function with.
* @param pf A given parser to bind the given function with.
* @param pg A given parser to bind the given function with.
* @return A new parser after performing the map, then final join.
*/
public Parser bind(final Parser pb, final Parser pc,
final Parser pd, final Parser pe,
final Parser pf, final Parser pg,
final F>>>>>> f) {
return pg.apply(bind(pb, pc, pd, pe, pf, f));
}
/**
* Binds the given function across the parsers with a final join.
*
* @param f The function to apply to the element of the parsers.
* @param pb A given parser to bind the given function with.
* @param pc A given parser to bind the given function with.
* @param pd A given parser to bind the given function with.
* @param pe A given parser to bind the given function with.
* @param pf A given parser to bind the given function with.
* @param pg A given parser to bind the given function with.
* @param ph A given parser to bind the given function with.
* @return A new parser after performing the map, then final join.
*/
public Parser bind(final Parser pb, final Parser pc,
final Parser pd, final Parser pe,
final Parser pf, final Parser pg,
final Parser ph,
final F>>>>>>> f) {
return ph.apply(bind(pb, pc, pd, pe, pf, pg, f));
}
/**
* Binds anonymously, ignoring the result value.
*
* @param p The parser to bind with.
* @return A parser after binding anonymously.
*/
public Parser sequence(final Parser p) {
return bind(a -> p);
}
/**
* Performs function application within a parser.
*
* @param p The parser returning a function value.
* @return A new parser after function application.
*/
public Parser apply(final Parser, E> p) {
return p.bind((F, Parser>) f1 -> map(f1));
}
/**
* Returns a parser that tries this parser and if it fails, then tries the given parser.
*
* @param alt The parser to try if this parser fails.
* @return A parser that tries this parser and if it fails, then tries the given parser.
*/
public Parser or(final F0> alt) {
return parser(i -> parse(i).f().sequence(alt.f().parse(i)));
}
/**
* Returns a parser that tries this parser and if it fails, then tries the given parser.
*
* @param alt The parser to try if this parser fails.
* @return A parser that tries this parser and if it fails, then tries the given parser.
*/
public Parser or(final Parser alt) {
return or(p(alt));
}
/**
* Returns a parser that tries this parser and if it fails, then tries the given parser. If both parsers fail, then
* append their errors with the given semigroup.
*
* @param alt The parser to try if this parser fails.
* @param s The semigroup to append error messages if both parsers fail.
* @return A parser that tries this parser and if it fails, then tries the given parser.
*/
public Parser or(final F0> alt, final Semigroup s) {
return parser(i -> parse(i).f().bind(e -> alt.f().parse(i).f().map(s.sum(e))));
}
/**
* Returns a parser that tries this parser and if it fails, then tries the given parser. If both parsers fail, then
* append their errors with the given semigroup.
*
* @param alt The parser to try if this parser fails.
* @param s The semigroup to append error messages if both parsers fail.
* @return A parser that tries this parser and if it fails, then tries the given parser.
*/
public Parser or(final Parser alt, final Semigroup s) {
return or(p(alt), s);
}
/**
* Returns a parser that negates this parser. If this parser succeeds, then the returned parser fails and vice versa.
*
* @param e The error message to fail with if this parser succeeds.
* @return A parser that negates this parser.
*/
public Parser not(final F0 e) {
return parser(i -> parse(i).isFail() ?
Validation.>success(result(i, unit())) :
Validation.>fail(e.f()));
}
/**
* Returns a parser that negates this parser. If this parser succeeds, then the returned parser fails and vice versa.
*
* @param e The error message to fail with if this parser succeeds.
* @return A parser that negates this parser.
*/
public Parser not(final E e) {
return not(p(e));
}
/**
* Returns a parser that repeats application of this parser zero or many times.
*
* @return A parser that repeats application of this parser zero or many times.
*/
public Parser, E> repeat() {
return repeat1().or(() -> value(Stream.nil()));
}
/**
* Returns a parser that repeats application of this parser one or many times.
*
* @return A parser that repeats application of this parser one or many times.
*/
public Parser, E> repeat1() {
return bind(a -> repeat().map(as -> as.cons(a)));
}
/**
* Maps the given function across this parser's error.
*
* @param f The function to map this parser's error with.
* @return A new parser with a new error type.
*/
public Parser mapError(final F f) {
return parser(i -> Parser.this.f.f(i).f().map(f));
}
/**
* Returns a parser that computes using the given function.
*
* @param f The function to construct the parser with.
* @return A parser that computes using the given function.
*/
public static Parser parser(final F>> f) {
return new Parser<>(f);
}
/**
* Constructs a parser that always returns the given value. The unital for a parser.
*
* @param a The value to consistently return from a parser.
* @return A parser that always returns the given value.
*/
public static Parser value(final A a) {
return parser(i -> success(result(i, a)));
}
/**
* Returns a parser that always fails with the given error.
*
* @param e The error to fail with.
* @return A parser that always fails with the given error.
*/
public static Parser fail(final E e) {
return parser(i -> Validation.fail(e));
}
/**
* Sequence the list of parsers through {@link #bind}.
*
* @param ps The parsers to sequence.
* @return A parser after sequencing.
*/
public static Parser, E> sequence(final List> ps) {
return ps.isEmpty() ?
Parser., E>value(List.nil()) :
ps.head().bind(a -> sequence(ps.tail()).map(cons_(a)));
}
/**
* Parsers that accept {@link Stream} input.
*/
public static final class StreamParser {
private StreamParser() {
}
/**
* Returns a parser that produces an element from the stream if it is available and fails otherwise.
*
* @param e The error to fail with if no element is available.
* @return A parser that produces an element from the stream if it is available and fails otherwise.
*/
public static Parser, I, E> element(final F0 e) {
return parser(is -> is.isEmpty() ?
Validation., I>>fail(e.f()) :
Validation., I>>success(result(is.tail()._1(), is.head())));
}
/**
* Returns a parser that produces an element from the stream if it is available and fails otherwise.
*
* @param e The error to fail with if no element is available.
* @return A parser that produces an element from the stream if it is available and fails otherwise.
*/
public static Parser, I, E> element(final E e) {
return element(p(e));
}
/**
* 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 Parser, I, E> satisfy(final F0 missing, final F sat,
final F f) {
return StreamParser.element(missing).bind(x -> f.f(x) ?
Parser., I, E>value(x) :
Parser., I, E>fail(sat.f(x)));
}
/**
* 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 Parser, I, E> satisfy(final E missing, final F sat, final F f) {
return satisfy(p(missing), sat, f);
}
}
/**
* Parsers that accept {@link Stream Stream<Character>} input.
*/
public static final class CharsParser {
private CharsParser() {
}
/**
* Returns a parser that produces a character if one is available or fails with the given error.
*
* @param e The error to fail with if a character is unavailable.
* @return A parser that produces a character if one is available or fails with the given error.
*/
public static Parser, Character, E> character(final F0 e) {
return StreamParser.element(e);
}
/**
* Returns a parser that produces a character if one is available or fails with the given error.
*
* @param e The error to fail with if a character is unavailable.
* @return A parser that produces a character if one is available or fails with the given error.
*/
public static Parser, Character, E> character(final E e) {
return character(p(e));
}
/**
* Returns a parser that produces the given character or fails otherwise.
*
* @param missing The error if no character is available.
* @param sat The error if the produced character is not the one given.
* @param c The character to produce in the parser.
* @return A parser that produces the given character or fails otherwise.
*/
public static Parser, Character, E> character(final F0 missing, final F sat,
final char c) {
return StreamParser.satisfy(missing, sat, x -> x == c);
}
/**
* Returns a parser that produces the given character or fails otherwise.
*
* @param missing The error if no character is available.
* @param sat The error if the produced character is not the one given.
* @param c The character to produce in the parser.
* @return A parser that produces the given character or fails otherwise.
*/
public static Parser, Character, E> character(final E missing, final F sat,
final char c) {
return character(p(missing), sat, c);
}
/**
* 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 Parser, Stream, E> characters(final F0 missing, final int n) {
return n <= 0 ?
Parser., Stream, E>value(Stream.nil()) :
character(missing).bind(characters(missing, n - 1), Stream.cons_());
}
/**
* 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 Parser, Stream, E> characters(final E missing, final int n) {
return characters(p(missing), n);
}
/**
* 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 Parser, Stream, E> characters(final F0 missing,
final F sat,
final Stream cs) {
return cs.isEmpty() ?
Parser., Stream, E>value(Stream.nil()) :
character(missing, sat, cs.head()).bind(characters(missing, sat, cs.tail()._1()), Stream.cons_());
}
/**
* 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 Parser, Stream, E> characters(final E missing,
final F sat,
final Stream cs) {
return characters(p(missing), sat, cs);
}
/**
* Returns a parser that produces the given string 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 string.
* @param s The string to produce.
* @return A parser that produces the given string or fails otherwise.
*/
public static Parser, String, E> string(final F0 missing, final F sat,
final String s) {
return characters(missing, sat, List.fromString(s).toStream()).map(cs -> List.asString(cs.toList()));
}
/**
* Returns a parser that produces the given string 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 string.
* @param s The string to produce.
* @return A parser that produces the given string or fails otherwise.
*/
public static Parser, String, E> string(final E missing, final F sat,
final String s) {
return string(p(missing), sat, s);
}
/**
* Returns a parser that produces a digit (0 to 9).
*
* @param missing The error if there is no character on the stream to produce a digit with.
* @param sat The error if the produced character is not a digit.
* @return A parser that produces a digit (0 to 9).
*/
public static Parser, Digit, E> digit(final F0 missing, final F sat) {
return StreamParser.satisfy(missing, sat, c -> Character.isDigit(c)).map(c1 -> Digit.fromChar(c1).some());
}
/**
* Returns a parser that produces a digit (0 to 9).
*
* @param missing The error if there is no character on the stream to produce a digit with.
* @param sat The error if the produced character is not a digit.
* @return A parser that produces a digit (0 to 9).
*/
public static Parser, Digit, E> digit(final E missing, final F sat) {
return digit(p(missing), sat);
}
/**
* Returns a parser that produces a lower-case character.
*
* @param missing The error if there is no character on the stream to produce a lower-case character with.
* @param sat The error if the produced character is not a lower-case character.
* @return A parser that produces a lower-case character.
* @see Character#isLowerCase(char)
*/
public static Parser, Character, E> lower(final F0 missing, final F sat) {
return StreamParser.satisfy(missing, sat, c -> Character.isLowerCase(c));
}
/**
* Returns a parser that produces a lower-case character.
*
* @param missing The error if there is no character on the stream to produce a lower-case character with.
* @param sat The error if the produced character is not a lower-case character.
* @return A parser that produces a lower-case character.
* @see Character#isLowerCase(char)
*/
public static Parser, Character, E> lower(final E missing, final F sat) {
return lower(p(missing), sat);
}
/**
* Returns a parser that produces a upper-case character.
*
* @param missing The error if there is no character on the stream to produce a upper-case character with.
* @param sat The error if the produced character is not a upper-case character.
* @return A parser that produces a upper-case character.
* @see Character#isUpperCase(char)
*/
public static Parser, Character, E> upper(final F0 missing, final F sat) {
return StreamParser.satisfy(missing, sat, c -> Character.isUpperCase(c));
}
/**
* Returns a parser that produces a upper-case character.
*
* @param missing The error if there is no character on the stream to produce a upper-case character with.
* @param sat The error if the produced character is not a upper-case character.
* @return A parser that produces a upper-case character.
* @see Character#isUpperCase(char)
*/
public static Parser, Character, E> upper(final E missing, final F sat) {
return upper(p(missing), sat);
}
/**
* Returns a parser that produces a defined character.
*
* @param missing The error if there is no character on the stream to produce a defined character with.
* @param sat The error if the produced character is not a defined character.
* @return A parser that produces a defined character.
* @see Character#isDefined(char)
*/
public static Parser, Character, E> defined(final F0 missing, final F sat) {
return StreamParser.satisfy(missing, sat, c -> Character.isDefined(c));
}
/**
* Returns a parser that produces a defined character.
*
* @param missing The error if there is no character on the stream to produce a defined character with.
* @param sat The error if the produced character is not a defined character.
* @return A parser that produces a defined character.
* @see Character#isDefined(char)
*/
public static Parser, Character, E> defined(final E missing, final F sat) {
return defined(p(missing), sat);
}
/**
* Returns a parser that produces a high-surrogate character.
*
* @param missing The error if there is no character on the stream to produce a high-surrogate character with.
* @param sat The error if the produced character is not a high-surrogate character.
* @return A parser that produces a high-surrogate character.
* @see Character#isHighSurrogate(char)
*/
public static Parser, Character, E> highSurrogate(final F0 missing,
final F sat) {
return StreamParser.satisfy(missing, sat, c -> Character.isHighSurrogate(c));
}
/**
* Returns a parser that produces a high-surrogate character.
*
* @param missing The error if there is no character on the stream to produce a high-surrogate character with.
* @param sat The error if the produced character is not a high-surrogate character.
* @return A parser that produces a high-surrogate character.
* @see Character#isHighSurrogate(char)
*/
public static Parser, Character, E> highSurrogate(final E missing,
final F sat) {
return highSurrogate(p(missing), sat);
}
/**
* Returns a parser that produces an identifier-ignorable character.
*
* @param missing The error if there is no character on the stream to produce an identifier-ignorable character with.
* @param sat The error if the produced character is not an identifier-ignorable character.
* @return A parser that produces an identifier-ignorable character.
* @see Character#isIdentifierIgnorable(char)
*/
public static Parser, Character, E> identifierIgnorable(final F0 missing,
final F sat) {
return StreamParser.satisfy(missing, sat, c -> Character.isIdentifierIgnorable(c));
}
/**
* Returns a parser that produces an identifier-ignorable character.
*
* @param missing The error if there is no character on the stream to produce an identifier-ignorable character with.
* @param sat The error if the produced character is not an identifier-ignorable character.
* @return A parser that produces an identifier-ignorable character.
* @see Character#isIdentifierIgnorable(char)
*/
public static Parser, Character, E> identifierIgnorable(final E missing,
final F sat) {
return identifierIgnorable(p(missing), sat);
}
/**
* Returns a parser that produces an ISO control character.
*
* @param missing The error if there is no character on the stream to produce an ISO control character with.
* @param sat The error if the produced character is not an ISO control character.
* @return A parser that produces an ISO control character.
* @see Character#isISOControl(char)
*/
public static Parser, Character, E> isoControl(final F0 missing,
final F sat) {
return StreamParser.satisfy(missing, sat, c -> Character.isISOControl(c));
}
/**
* Returns a parser that produces an ISO control character.
*
* @param missing The error if there is no character on the stream to produce an ISO control character with.
* @param sat The error if the produced character is not an ISO control character.
* @return A parser that produces an ISO control character.
* @see Character#isISOControl(char)
*/
public static Parser, Character, E> isoControl(final E missing, final F sat) {
return isoControl(p(missing), sat);
}
/**
* Returns a parser that produces a Java identifier part character.
*
* @param missing The error if there is no character on the stream to produce a Java identifier part character with.
* @param sat The error if the produced character is not a Java identifier part character.
* @return A parser that produces a Java identifier part character.
* @see Character#isJavaIdentifierPart(char)
*/
public static Parser, Character, E> javaIdentifierPart(final F0 missing,
final F sat) {
return StreamParser.satisfy(missing, sat, c -> Character.isJavaIdentifierPart(c));
}
/**
* Returns a parser that produces a Java identifier part character.
*
* @param missing The error if there is no character on the stream to produce a Java identifier part character with.
* @param sat The error if the produced character is not a Java identifier part character.
* @return A parser that produces a Java identifier part character.
* @see Character#isJavaIdentifierPart(char)
*/
public static Parser, Character, E> javaIdentifierPart(final E missing,
final F sat) {
return javaIdentifierPart(p(missing), sat);
}
/**
* Returns a parser that produces a Java identifier start character.
*
* @param missing The error if there is no character on the stream to produce a Java identifier start character with.
* @param sat The error if the produced character is not a Java identifier start character.
* @return A parser that produces a Java identifier start character.
* @see Character#isJavaIdentifierStart(char)
*/
public static Parser, Character, E> javaIdentifierStart(final F0 missing,
final F sat) {
return StreamParser.satisfy(missing, sat, c -> Character.isJavaIdentifierStart(c));
}
/**
* Returns a parser that produces a Java identifier start character.
*
* @param missing The error if there is no character on the stream to produce a Java identifier start character with.
* @param sat The error if the produced character is not a Java identifier start character.
* @return A parser that produces a Java identifier start character.
* @see Character#isJavaIdentifierStart(char)
*/
public static Parser, Character, E> javaIdentifierStart(final E missing,
final F sat) {
return javaIdentifierStart(p(missing), sat);
}
/**
* Returns a parser that produces an alpha character.
*
* @param missing The error if there is no character on the stream to produce an alpha character with.
* @param sat The error if the produced character is not an alpha character.
* @return A parser that produces an alpha character.
* @see Character#isLetter(char)
*/
public static Parser, Character, E> alpha(final F0 missing, final F sat) {
return StreamParser.satisfy(missing, sat, c -> Character.isLetter(c));
}
/**
* Returns a parser that produces an alpha character.
*
* @param missing The error if there is no character on the stream to produce an alpha character with.
* @param sat The error if the produced character is not an alpha character.
* @return A parser that produces an alpha character.
* @see Character#isLetter(char)
*/
public static Parser, Character, E> alpha(final E missing, final F sat) {
return alpha(p(missing), sat);
}
/**
* Returns a parser that produces an alpha-numeric character.
*
* @param missing The error if there is no character on the stream to produce an alpha-numeric character with.
* @param sat The error if the produced character is not an alpha-numeric character.
* @return A parser that produces an alpha-numeric character.
* @see Character#isLetterOrDigit(char)
*/
public static Parser, Character, E> alphaNum(final F0 missing, final F sat) {
return StreamParser.satisfy(missing, sat, c -> Character.isLetterOrDigit(c));
}
/**
* Returns a parser that produces an alpha-numeric character.
*
* @param missing The error if there is no character on the stream to produce an alpha-numeric character with.
* @param sat The error if the produced character is not an alpha-numeric character.
* @return A parser that produces an alpha-numeric character.
* @see Character#isLetterOrDigit(char)
*/
public static Parser, Character, E> alphaNum(final E missing, final F sat) {
return alphaNum(p(missing), sat);
}
/**
* Returns a parser that produces a low-surrogate character.
*
* @param missing The error if there is no character on the stream to produce a low-surrogate character with.
* @param sat The error if the produced character is not a low-surrogate character.
* @return A parser that produces a low-surrogate character.
* @see Character#isLowSurrogate(char)
*/
public static Parser