Module: mona/combinators

Methods

and(parsers)

Returns a parser that succeeds if all the parsers given to it succeed. The returned parser uses the value of the last successful parser.

Parameters:

Name	Type	Argument	Description
parsers	Parser	<repeatable>	One or more parsers to execute.

Source:

• mona.js, line 500

Example

parse(and(token(), token()), "ab"); // => "b"

between(open, close, parser)

Returns a parser that results in a value between an opening and closing parser.

Parameters:

Name	Type	Description
open	Parser	Opening parser.
close	Parser	Closing parser.
parser	Parser	Parser to return the value of.

Source:

• mona.js, line 855

Example

parse(between(string("("), string(")"), token()), "(a)"); // => "a"

collect(parser, opts)

Returns a parser that results in an array of min to max matches of parser

Parameters:

Name	Type	Argument	Description
parser	Parser		Parser to match.
opts	Object	<optional>	Properties Name Type Argument Default Description min Integer <optional> 0 Minimum number of matches. max Integer <optional> Infinity Maximum number of matches.

Source:

• mona.js, line 803

Example

parse(collect(token()), "abcd"); // => ["a", "b", "c", "d"]

exactly(parser, n)

Returns a parser that results in an array of exactly n results for parser.

Parameters:

Name	Type	Description
parser	Parser	The parser to collect results for.
n	Integer	exact number of results to collect.

Source:

• mona.js, line 838

Example

parse(exactly(token(), 4), "abcd"); // => ["a", "b", "c", "d"]

followedBy(parser, moreParsers)

Returns a parser that returns the result of its first parser if it succeeds, but fails if any of the following parsers fail.

Parameters:

Name	Type	Argument	Description
parser	Parser		The value of this parser is returned if it succeeds.
moreParsers	Parser	<repeatable>	These parsers must succeed in order for followedBy to succeed.

Source:

• mona.js, line 699

Example

parse(followedBy(string("a"), string("b")), "ab"); // => "a"

maybe(parser)

Returns a parser that returns the result of parser if it succeeds, otherwise succeeds with a value of undefined without consuming input.

Parameters:

Name	Type	Description
parser	Parser	Parser to try.

Source:

• mona.js, line 569

Example

parse(maybe(token()), ""); // => undefined

not(parser)

Returns a parser that succeeds if parser fails. Does not consume.

Parameters:

Name	Type	Description
parser	Parser	parser to test.

Source:

• mona.js, line 583

Example

parse(and(not(string("a")), token()), "b"); // => "b"

or(parsers, label)

Returns a parser that succeeds if one of the parsers given to it suceeds. Uses the value of the first successful parser.

Parameters:

Name	Type	Argument	Description
parsers	Parser	<repeatable>	One or more parsers to execute.
label	String	<optional>	Label to replace the full message with.

Source:

• mona.js, line 524

Example

parse(or(string("foo"), string("bar")), "bar"); // => "bar"

range(start, end, parser, predicate)

Returns a parser that accepts a parser if its result is within range of start and end.

Parameters:

Name	Type	Argument	Default	Description
start	*			lower bound of the range to accept.
end	*			higher bound of the range to accept.
parser	Parser	<optional>	token()	parser whose results to test
predicate	Function	<optional>	function(x,y){return x<=y; }	Tests range

Source:

• mona.js, line 887

Example

parse(range("a", "z"), "d"); // => "d"

sequence(fun)

Returns a parser that will execute fun while handling the parserState internally, allowing the body of fun to be written sequentially. The purpose of this parser is to simulate do notation and prevent the need for heavily-nested bind calls.

The fun callback will receive a function s which should be called with each parser that will be executed, which will update the internal parserState. The return value of the callback must be a parser.

If any of the parsers fail, sequence will exit immediately, and the entire sequence will fail with that parser's reason.

Parameters:

Name	Type	Description
fun	SequenceFn	A sequence callback function to execute.

Source:

• mona.js, line 633

Example

mona.sequence(function(s) {
 var x = s(mona.token());
 var y = s(mona.string('b'));
 return mona.value(x+y);
});

skip(parser)

Returns a parser that skips input until parser stops matching.

Parameters:

Name	Type	Description
parser	Parser	Determines whether to continue skipping.

Source:

• mona.js, line 869

Example

parse(and(skip(string("a")), token()), "aaaab"); // => "b"

split(parser, separator, opts)

Returns a parser that returns an array of results that have been successfully parsed by parser, which were separated by separator.

Parameters:

Name	Type	Argument	Description
parser	Parser		Parser for matching and collecting results.
separator	Parser		Parser for the separator
opts	Object	<optional>	Properties Name Type Argument Default Description min Integer <optional> 0 Minimum length of the resulting array. max Integer <optional> 0 Maximum length of the resulting array.

Source:

• mona.js, line 723

Example

parse(split(token(), space()), "a b c d"); // => ["a","b","c","d"]

splitEnd(parser, separator, opts)

Returns a parser that returns an array of results that have been successfully parsed by parser, separated and ended by separator.

Parameters:

Name	Type	Argument	Description
parser	Parser		Parser for matching and collecting results.
separator	Parser		Parser for the separator
opts	Object	<optional>	Properties Name Type Argument Default Description enforceEnd Integer <optional> true If true, separator must be at the end of the parse. min Integer <optional> 0 Minimum length of the resulting array. max Integer <optional> Infinity Maximum length of the resulting array.

Source:

• mona.js, line 758

Example

parse(splitEnd(token(), space()), "a b c "); // => ["a", "b", "c"]

unless(notParser, moreParsers)

Returns a parser that works like and, but fails if the first parser given to it succeeds. Like and, it returns the value of the last successful parser.

Parameters:

Name	Type	Argument	Description
notParser	Parser		If this parser succeeds, unless will fail.
moreParsers	Parser	<repeatable>	Rest of the parses to test.

Source:

• mona.js, line 604

Example

parse(unless(string("a"), token()), "b"); // => "b"

Type Definitions

SequenceFn(s) → {Parser}

Called by sequence to handle sequential syntax for parsing. Called with an s() function that must be called each time a parser should be applied. The s() function will return the unwrapped value returned by the parser. If any of the s() calls fail, this callback will exit with an appropriate failure message, and none of the subsequent code will execute.

Note that this callback may be called multiple times during parsing, and many of those calls might partially fail, so side-effects should be done with care.

A sequence callback must return a Parser.

Parameters:

Name	Type	Description
s	Function	Sequencing function. Must be wrapped around a parser.

Source:

• mona.js, line 664

Returns:

parser - The final parser to apply before resolving sequence.

Type

Parser