Parserflow

Parserflow is a prototype of parser written in Dart inspire by pyrser and PetitParser. This parser aims to provide a simple tool to implement different type of parser like LL(k) or LR(k), by offering simple mechanism like hook or grammar definition.

Aims

The main objective of parserflow is to provide enough abstraction and functionality to easily implement the parser do you need.

Features

Parserflow allow you to :

• [DONE] Create your grammar by code like :

var myRule = (isDigit | isMathOperator) & isNum;

• [DONE] Use a comprehensive syntax to define quantity like

var myRule = (isDigit["*"] | isMathOperator["*"]) & isDigit[3]

• [DONE] Simply define hook

  var number = (has("-")["*"] & isNum)..name = "number";
  number.onParse.listen((i) {
    print("number: ${i.matchData}");
    i["value"] = int.parse(i.matchData.join());
  });

• [TO DO] Use directly some parser implementation like LL(k) or LR(k)
• [TO DO] Directly parse from a BNF

Example

Create rules and parse a simple string

Here a example of a simple rules creation and parse a simple string

import 'package:parserflow/parserflow.dart';

void main() {
    var s = "96-96*2";

    var r = isNum["?"] & isMathOperator & isNum & (isMathOperator["?"] & isNum)["*"];
    var a = r.consume(s);
    print(a);
}

Parse a simple math expression

Here a part of the example that you can find in 'example/math_expr.dart'

main() {
  var number = (has("-")["*"] & isNum)..name = "number";
  var op = hasRegExp(r'[+|-]')..name = "op";

  var expr = number & (op & number)["*"];

  var input = "968 + 2 - 20";
  var res = expr.check(input);
  var tree = res.matchTree();

  print(tree);
  print("${input} = ${visitChild(tree, [])[0]}");
}

Future

Actually my main focus is to make parserflow as easy as possible, but the second step will be to make it a quick as posible.

The Author

Actualy this library is developped by myself, if you have any idea, amelioration, bug, ... do not hesitate contacting me. G+ : +Kevin PLATEL Mail : Kevin PLATEL