Arcsecond Article

FullParser.js

const {
  between,
  many,
  choice,
  sequenceOf,
  char,
  whitespace,
  anythingExcept,
  possibly,
  regex,
  digits,
  anyOfString,
  str,
  recursiveParser,
  sepBy
} = require('arcsecond');

/***********************************
          Type Containers
 ***********************************/
const makeBasicType = typeName => value => ({
  type: typeName,
  value,
  toString: () => `${typeName}(${value})`
});

const makeMultiType = typeName => values => ({
  type: typeName,
  value: values,
  toString: () => `${typeName}(${values.map(v => v.toString()).join(', ')})`
});

const stringType = makeBasicType('String');
const numberType = makeBasicType('Number');
const booleanType = makeBasicType('Boolean');

const arrayType = makeMultiType('Array');
const objectType = makeMultiType('Object');

const keyValuePair = (key, value) => ({
  type: 'KeyValuePair',
  value: [key, value],
  toString: () => `KeyValuePair(${key.toString()}, ${value.toString()})`
});

const nullType = () => ({
  type: 'Null',
  value: null,
  toString: () => 'Null'
});


/***********************************
          Utility Parsers
 ***********************************/
const orEmptyString = parser => possibly (parser) .map(x => (x) ? x : '');
const joinedSequence = parsers => sequenceOf (parsers) .map(x => x.join(''));
const joinedMany = parser => many (parser) .map(x => x.join(''));
const whitespaceSurrounded = between (whitespace) (whitespace);
const betweenQuotes = between (char ('"')) (char ('"'));
const betweenSquareBrackets = between (char ('[')) (char (']'));
const betweenCurlyBrackets = between (whitespaceSurrounded (char ('{'))) (whitespaceSurrounded(char ('}')));
const commaSeparated = sepBy (whitespaceSurrounded (char (',')));

/***********************************
        Main Recursive Parser
 ***********************************/
const jsonParser = recursiveParser(() => choice ([
  nullParser,
  trueParser,
  falseParser,
  numberParser,
  stringParser,
  arrayParser,
  objectParser
]));


/***********************************
              Strings
 ***********************************/
const stringParser = betweenQuotes (joinedMany (choice ([
  joinedSequence ([
    char ('\\'),
    char ('"')
  ]),
  anythingExcept (char ('"'))
]))) .map(stringType);

/***********************************
              Numbers
 ***********************************/
const numberParser = joinedSequence ([
  orEmptyString (char ('-')),
  choice ([
    char ('0'),
    regex (/^[1-9][0-9]*/)
  ]),
  orEmptyString (joinedSequence ([
    char ('.'),
    digits
  ])),
  orEmptyString (joinedSequence([
    anyOfString ('eE'),
    orEmptyString (anyOfString ('-+')),
    digits
  ]))
]) .map (x => numberType(Number(x)));

/***********************************
              Nulls
 ***********************************/
const nullParser = str ('null') .map(nullType);

/***********************************
              Booleans
 ***********************************/
const trueParser = str ('true') .map(booleanType);
const falseParser = str ('false') .map(booleanType);

/***********************************
              Arrays
 ***********************************/
const arrayParser = betweenSquareBrackets (commaSeparated (jsonParser)) .map(arrayType);

const keyValuePairParser = sequenceOf ([
  stringParser,
  whitespaceSurrounded (char (':')),
  jsonParser
]) .map(([key, _, value]) => keyValuePair(key, value));

/***********************************
              Objects
 ***********************************/
const objectParser = betweenCurlyBrackets (commaSeparated (keyValuePairParser)) .map(objectType);

Why does betweenSquareBrackets not allow whitespace around the square brackets?