Parser Combinator in Kotlin

Objective

A parser combinator library implementation from scratch in Kotlin.

How to use

import

import lambdada.parsec.parser.* // combinators, e.g. string, char, not, ...
import lambdada.parsec.parser.Response.* // for reading the parser result (Accept, Reject)
import lambdada.parsec.io.Reader // for running parsers (Reader)

Run the parser

// The example for a `Parser<Char, List<String>>`
val foo: Parser<Char, List<Char>> = not(char(',')).rep
val input = Reader.string("hello, parsec!")
val result = foo(input)
when (result) {
    is Accept -> println("good")
    is Reject -> println("bad")
}
// good

Examples

CSV

// item    ::= [^,]*
// csvline ::= item (',' item)*

var item     = not(char(',')).optrep
val csvline  = item then (char(',') then item).optrep

Expressions

// SEXPR ::= '(' EXPR ')' | FLOAT
// EXPR  ::= SEXPR (('+'|'*') EXPR)?

fun SEXPR() =
    lazy { char('(') then EXPR() then char(')') or FLOAT }

fun EXPR() =
    lazy { SEXPR() then (charIn('+', '*') then EXPR()).opt }

Why this library

This material has been designed for a Lambdada session in order to explore the Kotlin language implementing a library with intensive function composition. A presentation of this library has been given during the first SunnyTech conference

License

Copyright 2018 D. Plaindoux.

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.