palladium02/tarser

Tarser

Tarser is the successor to my "parser-combinator" library.

Installation

npm install https://github.com/Palladium02/tarser.git

Documentation

char(c: string)

many(p: Parser)

many takes a parser which is then applied to the input. The parser will eat from the input until it can't. It may not eat anything.

many1(p: Parser)

Similar to many but many1 will eat at least once. If that is not possible this and all following parser will fail.

sequence(...ps: Parser[])

sequence takes a set of parsers which as the name implies we be working on the input one after another. As soon as one parser fails the whole sequence will fail and yield an error result.

word(w: string)

word converts a string into a parser that expects that string.

import {word} from 'tarser';

const Hello = word('Hello');

Hello.run('Hello World!');
//    ^? { type: 'ok', index: 6, input: 'Hello World!', value: ['H', 'e', 'l, 'l', 'o'] }

Here one might already see that word is just the combination of char and sequence as we receive ['H', 'e', 'l, 'l', 'o'] as parsed value. How we can change the parsed will be explained in the Converter section.

optional(p: Parser)

optional takes a parser that might but must not be satisfied by the input. Based on whether the parser was satisfied we advance the index.

choice(...ps: Parser[])

choice takes a set of parsers of which one must be satisfied. It will always take the first succeeding parser.

float

A parser that expects the string representation a floating point number.

digit

A parser that expects a singular digit.

whitespace

A parser that expects a whitespace character.

lazy

lazy takes a function that returns a parsers and only call the given function if needed allowing you to build recursive parsers. E.g. examples/array.ts

Converter

Parser return ParserStates containing a value field if the parser succeeded. These values might not have the shape you want. Parsers have a map method that allows you to convert the value field to a reasonable value. Tarser ships with a selection of converters for all built-in terminal parsers.

forDigit

import * as Tarser from 'tarser';

const digit = Tarser.digit.map(Converter.forDigit);

digit.run('1');
//    ^? { type: 'ok', index: 1, input: '1', value: 1 }

forFloat

import * as Tarser from 'tarser';

const float = Tarser.float.map(Converter.forFloat);

float.run('-1.2');
//    ^? { type: 'ok', index: 1, input: '1', value: -1.2 }

Examples

Examples can be found in the examples directory of this repo.