combine

An implementation of parser combinators for Deno. If you're looking for production-ready code use Parsimmon.

Example

const helloWorldParser = seq(
  str("Hello,"),
  optional(space()),
  mapJoin(manyTill(anyChar(), str("!"))),
);

const worldRes = helloWorldParser({
  text: "Hello, World!",
  index: 0,
});

/**
{
  success: true,
  ctx: {
    text: "Hello, World!",
    index: 13
  },
}
*/

const nameParser = map(helloWorldParser, ([, , name]) => name);
const nameRes = nameParser({
  text: "Hello, Joe Doe!",
  index: 0,
});

/**
{
  success: true,
  value: "Joe Doe!",
  ctx: {
    text: "Hello, Joe Doe!",
    index: 15
  },
}
*/

For more examples, take a look at tests.

About

A parser combinator is a function that takes several parsers as input, and returns a new parser. combine defines a few such combinators depending on how the parsers should be combined, seq which takes a list of parser that are applied sequentially, oneOf which tries all parsers sequentially and applies the first one that's succesful, furthest which tries all parsers and applies the one that consumes the most input and more.

Most included parsers are LL(1), with some notable exceptions such as str and regex. Other LL(k) parsers library are the result of using combinators and are included for convenience, like signed, horizontalSpace and others.

A couple of common utility functions are also included.