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scriptNOP

A framework for NOPNotification-oriented programming paradigm (NOP[1]) implemented in TypeScript.

In the NOPNotification Oriented Paradigm (NOP), there are the “factual and causal smart-entities named as Fact Base Elements (FBEs) and Rules that are related to another collaborative notifier smart-entities. Each FBE is related to Attributes and Methods, whereas each Rule to Premises-Conditions and Actions-Instigations. All these entities collaboratively carry out the inference process using NOPNotifications, providing solutions to deficiencies of current paradigms” [1].

This implementation provides state-of-the-art features of NOP, in TypeScript, exploring the current limits of object orientation and imperative programming, parallel programming and concurrent programming. The implementation has no dependencies on other libraries and can be used in any TypeScript/JavaScript runtime or browsers. Also, this implementation is REACTIVE IN DEPTH and optionally accepts FUZZY[2] parameters and CUSTOM FUNCTIONS like sum of a weighted input of a NEURON[3], and you can still combine it all at the same time.

Contents

Sample application

This program contains an example of an application called “Target shooting”. There is the main thread (state manager), where all the Fact Base Elements are, and there are the secondary threads where the Rules are.

main.ts (main thread):

import {
  App,
  delay,
  FactBaseElement,
} from "https://deno.land/x/script_nop/mod.ts";
App.init({
  numThreads: 1,
  extensionsURLs: [ //for URL to local file: new URL("./my_file.js", import.meta.url).href
    "https://deno.land/x/script_nop/src/extensions/deepEqual.ts",
  ],
  rulesURL: "https://deno.land/x/script_nop/example/rules.ts",
  onNotification: (n: any) => console.log(n), //Using history as a debugger
});
/*
  * Example: Target shooting aplication
  */
class Shooter extends FactBaseElement {
  constructor(fbeName: string) {
    super(fbeName);
  }
  shoot() {
    super.notify(
      {
        gun: {
          bullets: 5,
          pull_trigger: false,
        },
        target: false,
      },
    );
  }
}
const shooter1 = new Shooter("shooter1_name");
await delay(3000); //Wait for all threads to be started
shooter1.shoot();

rules.ts (secondary threads):

import { Rule } from "https://deno.land/x/script_nop/mod.ts";
const rule1 = new Rule(
  {
    name: "rule1_name",
    condition: {
      premise: {
        fbe: "shooter1_name",
        attr: "gun.bullets",
        is: ">",
        value: 0,
      },
    },
    action: async (context: any) => {
      console.log("loaded gun!!!");
      const bullets = await context["shooter1_name"].get("gun.bullets"); // get FBE Attribute value (using notifications between Attributes and Conditions).
      context["shooter1_name"].notify({ // notify FBE, changes will be automatically sent to the state manager thread.
        target: true,
      }, "IGNORE_MISSING"); //with "IGNORE_MISSING", missing attributes in will not be considered excluded.
      //Action to Rule notifications are control mechanisms for the NxN relationship between Rules.
      return { gun_loaded: true }; //send notification to the state manager thread, if you have Rules that depend on this Rule activated, they will also receive this notification.
    },
  },
);

To avoid problems with threads, start the “rules.ts” file with the Rules instantiations, putting operations like “await” at the end of the file, after such instantiations.

Defining Conditions

Conditions are implemented in a tree structure, easy for humans to understand. Note that the “.” is reserved in this implementation for path notation, and this implementation handles circular references. See examples of Conditions:

//------------------------- TYPES OF CONDITIONS ----------------------
//----------------WITH ONE PREMISE:
const c: Condition = {
  premise: {
    fbe: "shooter1_name", //Fact Base Element name.
    attr: "target.person.age", //path notation
    is: ==, //"==", ">", "<", etc. Or: function name (registered extension).
    value: true, //non-reactive constant.
  },
}
//----------------WITH ONE PREMISE (WITH REACTIVE VALUE):
const c: Condition = {
  premise: {
    fbe: "shooter1_name", //Fact Base Element name.
    attr: "target.person.age", //path notation
    is: ==, //"==", ">", "<", etc. Or: function name (registered extension).
    value: { //reactive Attribute
      fbe: "shooter2_name",
      attr: "target.person.age",
    },
  }
}
//----------------WITH ONE SELF-EVALUATED PREMISE:
//The value of the respective attr is already the result of the Premise.
const c: Condition = {
  premise: {
    fbe: "shooter2_name", //Fact Base Element name.
    attr: "target.person.age" //path notation.
  }
}
const c: Condition = {
  premise: {
    fbe: "layer1_name", //Fact Base Element name.
    attr: "neurons.0", //path notation.
    is: "sumOfWeights", //custom function name, function out is result of the Premise, FBE.attr is input of function
  }
}
//----------------WITH OR, AND, XOR
const c: Condition = {
  and: [ //keys: "or", "and", "xor"
    //ARRAY of sub Conditions.
  ]
}
//----------------WITH custom function
const c: Condition = {
  is: "+", // "function name (registered extension) or operator (+, *, etc)",
  sub_conditions: [ //this vector is the input parameter of the function
    //ARRAY of sub Conditions.
  ]
}
//----------------WITH negation
const c: Condition = {
  not: c2, //c2 is one object of type Condition.
}
//----------------WITH OPTIONAL parameters ​​for FUZZY logic:
//Fuzzy parameters are optional and combinable with any type of Condition.
const c: Condition = {
  // ... (Condition parameters) ...
  min_threshold: 0.2, //number (or reactive Attribute) for fuzzy logic (optional), "if Condition < min_threshold".
  max_threshold: 0.8, //number (or reactive Attribute) for fuzzy logic (optional), "if Condition > max_threshold", you can set a defined range, defining min_threshold and max_threshold at the same time.
}
const c: Condition = {
  // ... (Condition parameters) ...
  exactly: 0.5, //number (or reactive Attribute) for fuzzy logic (optional), the result of the expression must be equal to the value.
}
*/

Condition with extensions

There is also an extension interface for named functions, which are used as cuttomized functions in Premises and Conditions. These extensions are defined at the beginning of the main thread by the “extensionsURLs” parameter, but they can also be defined manually in the Rules file:

DataMap.registerExtensions([customFunc2]);

How to use extensions:

/*
In Premises:
deepEqual = function with name "deepEqual", ex: export default function deepEqual(items: any[]): any { ...
"items" is the result of "FBE.attr" (index 0) and the result of "FBE.value" (index 1); the vector is size 2 or size 1 for self-evaluated Premises.
*/
const c: Condition = {
  premise: {
    fbe: "shooter1_name",
    attr: "character",
    is: "deepEqual", //FUNCTION NAME HERE
    value: { name: "joe", age: 25 }, //Non-reactive CONSTANT, but it could also be an Attribute
  },
};
/*
In Conditions:
custonFunc = function with name "custonFunc2", ex: export default function custonFunc2(items: any[]): any { ...
"items" is an array of result of Conditions ("sub_conditions" parameter).
*/
const c: Condition = {
  is: "customFunc2", //FUNCTION NAME HERE, the "is" can also be operators like "+", "*", etc. Operators like "and" must be represented by their name in the language ("&&").
  sub_conditions: [ //"sub_conditions" only exists when the "is" attribute in a Condition is filled
    {
      premise: {
        fbe: "shooter1_name",
        attr: "gun.bullets",
        is: "==",
        value: true, //Non-reactive constant, but it could also be an Attribute.
      },
    },
  ],
};

Combination of Conditions

A combination of different types of Conditions together is possible. Example with simple logic, fuzzy logic and custom functions:

const c: Condition = {
  or: [
    {
      not: {
        is: "ReLU", //custom function name in Condition, input is sub_conditions Array
        sub_conditions: [
          {
            premise: {
              fbe: "layer1_name",
              attr: "neurons.0", //paths with .N is valid for vectors
              is: "sumOfWeights", //custom function name in Premise, input is FBE.attr
            },
          },
        ],
      },
    },
    {
      premise: {
        fbe: "shooter1_name",
        attr: "gun.distance",
      },
      min_threshold: 0.2, //fuzzy parameter, combinable with any type of Condition
    },
    {
      premise: {
        fbe: "shooter1_name",
        attr: "gun.pull_trigger",
        is: "==", //simple logic
        value: true,
      },
    },
  ],
};

In the library package the extension functions “deepEqual”, which checks in depth if two objects are the same, i.e. compares their parameters, subparameters and etc. It is possible for example an extension function that represents a sum of weighted weights of a neuron, it can also be combined with fuzzy logic for the activation threshold of the same.

Rules

See also options for instantiating a Rule:

type RuleOptions = {
  name: string;
  condition: Condition;
  action: (
    context: { [key: string]: FactBaseElement },
  ) => Promise<any> | any;
  delay?: number;
  depends?: string[];
};

Instructions to run this project

Basically you just need to clone the project and install the Deno runtime.

# clone project
git clone https://github.com/hviana/scriptNOP.git
# enter the project directory
cd scriptNOP
# install Deno (Mac, Linux)
curl -fsSL https://deno.land/install.sh | sh
# install Deno (Windows/PowerShell)
iwr https://deno.land/install.ps1 -useb | iex
# run project example:
deno run --unstable --allow-read --allow-net --allow-write main.ts
# bundle scriptNOP lib to any runtime or web browsers:
deno bundle mod.ts nop.js

Particularities of this implementation

The framework has several facilities for the developer. Conditions can be composed of SubConditions and can have parameters coming from Attributes notifications, such as fuzzy parameters. Actions have a paradigm-independent nature and are represented directly by a reference to a procedure. This Action procedure can directly notify values to FBEs, and notify and receive notifications from Attributes in order to make changes to the fact base. Finally, a Rule can have other N Rules as dependencies or be a dependency for other N Rules (NxN cardinality).

To support all these features, the core of the original NOP was modified. Basically, the Instigations and Methods entities were removed, and several new notification paths were added. For the composition between Conditions, notifications from Conditions to Conditions were created. For the parameters of Conditions, notifications of Attributes for Conditions were created.

Actions, since they are a direct reference to a paradigm-independent procedure, need a drastic amount of modifications. When using imperative programming mechanisms, for example, it is unpredictable to know what the code execution flow will be since there may be, for example, code suspension mechanisms such as an “IF”, making it impossible to predict which notifications will be sent and received by this Action procedure. To solve this problem, this Action procedure has access to routines that explicitly notify and receive notifications. When needing an Attribute, there is an asynchronous routine called “get” that sends a notification to the respective Attribute that symbolizes a request to its updated value, and the Attribute sends to the Action procedure a notification with its updated value that is captured by the routine “get”. In the end, the “get” routine returns the updated value of the Attribute inside the Action procedure. To notify FBEs, there is also a routine called “notify”, which transmits to an FBE a notification containing a set of new values ​​for that FBE.

To implement the NxN cardinality dependency between Rules, Actions for Rules notifications are also implemented. When an Action of a Rule “R1” finishes its execution, it notifies all Rules that have “R1” as a dependency.

FBEs notify attributes in depth. That is, if an Attribute “A2” is inside the Attribute “A1”, notifications about “A2” will trigger notifications about “A1”. It is possible to visualize the behavior:

//initial values.
fbe.notify(
  {
    a: {
      b: {
        c: "foo",
      },
      d: true,
    },
  },
);
/*
Premises that use "a", "a.b" or "a.b.c" will be notified.
Premises that use only "a.d" are not notified, since
the value of "a.d" has not been modified.
*/
fbe.notify(
  {
    a: {
      b: {
        c: "bar",
      },
      d: true,
    },
  },
);
await fbe.get("a.b"); //returns "a.b" Attribute.

The framework also has a debugger function that intercepts all notifications between NOP core entities. In this way, it is possible, for example, to save this information in a history or print it on the screen.

An application with this framework can result in a “freeze” of the program if infinite changes of Fact Base Elements states start, given the respective Actions. To minimize this problem and at the same time implement the priority idea of Actions and Rules, when creating a Rule it is possible to insert an optional delay for its Action. Note that there is no need for a “Dispatcher” to queue NOPNotifications, as such NOPNotifications are implemented using async functions with delay.

The code is very dense, although every detail has been thought of in order to favor readability and avoid replication. With TypeScript, we have a new way of defining types and programming in an object-oriented style compared to classic object-oriented languages ​​such as Java and C++, which drastically reduces the amount of code. See the following code snippet:

export interface Attribute {
  fbe: string;
  attr: string;
}
export interface Premise extends Attribute {
  is: string;
  value: any | Attribute;
}
// ...
interface ConditionWithXor extends FuzzyCondition {
  xor: [Condition, Condition, ...Condition[]]; //min 2 Conditions
}
export type Condition =
  | ConditionWithNot
  | ConditionWithPremise
  | ConditionWithAnd
  | ConditionWithOr
  | ConditionWithXor
  | ConditionWithFunc;
//...
export class Rule {
  static #extensions: {
    [key: string]: Function;
  } = {};
  static initialized: boolean = false;
  #transpiledCondition: (
    context: { [key: string]: FactBaseElement },
  ) => Promise<boolean>;

References

[1] J. M. Simão, C. A. Tacla, P. C. Stadzisz and R. F. Banaszewski, “NOPNotification Oriented Paradigm (NOP) and Imperative Paradigm: A Comparative Study,” Journal of Software Engineering and Applications, Vol. 5 No. 6, 2012, pp. 402-416. doi: https://www.doi.org/10.4236/jsea.2012.56047

[2] Melo, Luiz Carlos & Fabro, João & Simão, Jean. (2015). Adaptation of the NOPNotification Oriented Paradigm (NOP) for the Development of Fuzzy Systems. Mathware& Soft Computing. 22. 1134-5632. url: https://www.researchgate.net/publication/279178301_Adaptation_of_the_NOPNotification_Oriented_Paradigm_NOP_for_the_Development_of_Fuzzy_Systems

[3] F. Schütz, J. A. Fabro, C. R. E. Lima, A. F. Ronszcka, P. C. Stadzisz and J. M. Simão, “Training of an Artificial Neural Network with Backpropagation algorithm using NOPNotification oriented paradigm,” 2015 Latin America Congress on Computational Intelligence (LA-CCI), 2015, pp. 1-6, doi: https://doi.org/10.1109/LA-CCI.2015.7435978

About

Author: Henrique Emanoel Viana, a Brazilian computer scientist, enthusiast of web technologies, cel: +55 (41) 99999-4664. URL: https://sites.google.com/site/henriqueemanoelviana

Improvements and suggestions are welcome!