/**
* A grammar for JSON. Copied and adapted from
* https://github.com/jon-hanson/parsecj/blob/master/src/test/java/org/javafp/parsecj/json/Grammar.java
*/
class Grammar {
private static <T> Parser<Character, T> tok(Parser<Character, T> p) {
return p.bind(x -> wspaces.then(retn(x)));
}
private static final Parser.Ref<Character, JValue> jvalue = Parser.ref();
private static final Parser<Character, JValue> jnull =
tok(string("null")).then(retn(jNull().asJValue())).label("null");
private static final Parser<Character, Boolean> jtrue =
tok(string("true").then(retn(Boolean.TRUE)));
private static final Parser<Character, Boolean> jfalse =
tok(string("false").then(retn(Boolean.FALSE)));
private static final Parser<Character, JValue> jbool =
tok(jtrue.or(jfalse).bind(b -> retn(jBoolean(b).asJValue()))).label("boolean");
private static final Parser<Character, BigDecimal> bigdecimal =
bind(regex("-?(?:0|[1-9]\\d*)(?:\\.\\d+)?(?:[eE][+-]?\\d+)?"), s -> retn(new BigDecimal(s)))
.label("bigdecimal");
private static final Parser<Character, JValue> jnumber =
tok(bigdecimal.bind(d -> retn(jNumber(d).asJValue()))).label("number");
private static final Parser<Character, Byte> hexDigit =
satisfy((Character c) -> Character.digit(c, 16) != -1)
.bind(c -> retn((byte) Character.digit(c, 16)))
.label("hex digit");
private static final Parser<Character, Character> uni =
hexDigit
.bind(
d0 ->
hexDigit.bind(
d1 ->
hexDigit.bind(
d2 ->
hexDigit.bind(
d3 -> retn((d0 << 0x3) & (d1 << 0x2) & (d2 << 0x1) & d0)))))
.bind(i -> retn((char) i.intValue()));
private static final Parser<Character, Character> esc =
choice(
chr('"'),
chr('\\'),
chr('/'),
chr('b').then(retn('\b')),
chr('f').then(retn('\f')),
chr('n').then(retn('\n')),
chr('r').then(retn('\r')),
chr('t').then(retn('\t')),
chr('u').then(uni))
.label("escape character");
private static final Parser<Character, Character> stringChar =
(chr('\\').then(esc)).or(satisfy(c -> c != '"' && c != '\\'));
private static final Parser<Character, String> jstring =
tok(between(chr('"'), chr('"'), many(stringChar).bind(l -> retn(IList.listToString(l)))))
.label("string");
private static final Parser<Character, JValue> jtext =
jstring.bind(s -> retn(jString(s).asJValue())).label("text");
private static final Parser<Character, JValue> jarray =
between(tok(chr('[')), tok(chr(']')), sepBy(jvalue, tok(chr(','))))
.bind(l -> retn(jArray(IList.toList(l)).asJValue()))
.label("array");
private static final Parser<Character, Tuple2<String, JValue>> jfield =
jstring.bind(name -> tok(chr(':')).then(jvalue).bind(value -> retn(tuple(name, value))));
private static final Parser<Character, JValue> jobject =
between(
tok(chr('{')),
tok(chr('}')),
sepBy(jfield, tok(chr(','))).bind(lf -> retn(jObject(lf).asJValue())))
.label("object");
static {
jvalue.set(choice(jnull, jbool, jnumber, jtext, jarray, jobject).label("JSON value"));
}
private static final Parser<Character, JValue> parser = wspaces.then(jvalue);
static Reply<Character, JValue> parse(String str) {
return parser.parse(State.of(str));
}
}
private static <T> Parser<Character, T> tok(Parser<Character, T> p) {
return p.bind(x -> wspaces.then(retn(x)));
}
static Reply<Character, JValue> parse(String str) {
return parser.parse(State.of(str));
}