flurine_lambda 0.9.3+1

A starting point for Dart libraries or applications.

A library to generate simple formula and get values from it in iterative manner.

Usage

A simple usage example:

import 'package:lambda/flurine_lambda.dart';

const TIME = 'tm';
const CONCAT = 'cc';

void main() async {
  Handler.registerMany({
    CONST: () => ConstHandler(),
    TIME: () => TimeHandler(),
    CONCAT: () => ConcatHandler(),
  });
  await Vein.init();
  final lambda = Lambda.parse('\$cc("Hello : ",tm(2))\$');
  await lambda.execute();
  lambda.vein.listen(onData);
}

void onData(data) {
  print(data);
}

In above formula :

- 'tm','cc' is Lambda keyword,
- 2 (integer),"Hello : " (String) are arguments which are handled by TimeHandler,ConcatHandler.
- whole lambda should be wrapped between $ sign.
- handlers should be registerd first.

Here whole data is processed behind single Isolate (here [Vein]) which should be initialized first.

Break Down :

- Here 'tm(2)' will generate values repeatively as defined in TimeHandler ( Every 2 seconds).
- Output of 'tm(2)' will appended to "Hello : " (first parameter) as defined in ConcatHandler.

So, this will print values every two seconds ...

Hello : 12
Hello : 14
Hello : 16
Hello : 18
.
.
.

I don't know where you can use this library or an idea like this but here it is.

class TimeHandler extends Handler {

  @override
  Future compute() async {
    return DateTime.now().second;
  }

  @override
  Duration get repeatingDuration => Duration(seconds:params.last);
}

class CounterHandler extends Handler {

  @override
  Duration get repeatingDuration => null;

  int begin, end, step,current;

  @override
  set params(List params) {
    this.params = params;
    begin = params[0];
    end = params[1];
    step = params[2];
    current = params[3];
  }

  @override
  Future compute() async {
    if (current == null || current > end) current = begin;
    int temp = current;
    current = current + step;
    return temp;
  }
}

class ConcatHandler extends Handler{

  @override
  Duration get repeatingDuration => null;

  @override
  Future compute() async{
    return params.join();
  }

}