Angel \”Java\” Lopez on Blog

December 4, 2014

New Month’s Resolutions: December 2014

It’s time to review past month’s resolutions:

– Give a talk about JavaScript and Artificial Intelligence [complete] see repo see talk read Spanish post
– Neural network in JavaScript example [complete] see repo
– Genetic Algorithms in JavaScript example [complete] see repo
– More Code Generation using AjGenesis for NodeJs [pending]
– Basic Script Language for C# [pending]
– Improve SimpleScript for JavaScript [complete] see repo

Also, I was working on:

– Improve SimpleLisp, Lisp to JavaScript compiler [complete] see repo
– Improve RuScript, Ruby interpreter in JavaScript [complete] see repo
– Improve RustScript, Rust-like interpreter in JavaScript [complete] see repo
– Create SimpleDT, simple decision tree in JavaScript [complete] see repo
– Improve ClojSharp, Clojure-like interpreter in C# [complete] see repo
– Backgammon evaluation page [complete] see repo

This new month’s resolutions:

– Add distributed features to AjElr, Erlang-like interpreter in C#
– Improve ClojSharp
– Improve SimpleLisp
– Code generation with AjGenesis for Node
– Start Basic Script Language for C#

Stay tuned!

Angel “Java” Lopez

September 16, 2014

RuScript, Ruby Interpreter in JavaScript (1) The Project

Filed under: JavaScript, NodeJs, Open Source Projects, Ruby, RuScript — ajlopez @ 5:08 pm

When I have free time, I’m working on:

I’m writing the code following the TDD (Test-Driven Development) workflow (see commit history)

The idea is to have a Ruby interpreter written in JavaScript, so it can run at the browser, or at the server with Node.js. I’m not implementing a compiler yet, because I want to do “baby steps”, and because Ruby semantic could be different to JavaScript one. Ie, the resolution of methods, or check if a variable is local to a function or not, are examples of divergences between the languages. So, I decided to write an interpreter.

I’m applying “dog fooding”: the parser is written using:

I’m applying SimpleGrammar in other projects, like RustScript. There is an implementation in C#, too, named GrammGen). A fragment of the defined rules for RuScript parser:

// Expression Level 1
get('Expression1', 'Plus', 'Expression0')
    .generate('Expression1', function (values) { return new AddExpression(values[0], values[2]); }),
get('Expression1', 'Minus', 'Expression0')
    .generate('Expression1', function (values) { return new SubtractExpression(values[0], values[2]); }),

// Expression Level 0
get('Expression0', 'Multiply', 'Term')
    .generate('Expression0', function (values) { return new MultiplyExpression(values[0], values[2]); }),
get('Expression0', 'Divide', 'Term')
    .generate('Expression0', function (values) { return new DivideExpression(values[0], values[2]); }),

// Term
get('Term', 'LeftBracket', 'ExpressionList', 'RightBracket')
    .generate('Term', function (values) { return new IndexedExpression(values[0], values[2]); }),
get('@@', 'Name').generate('ClassVariable', 
    function (values) { return new ClassVariableExpression(values[1].getName()); }),
get('@', 'Name').generate('InstanceVariable', 
    function (values) { return new InstanceVariableExpression(values[1].getName()); }),
get('LeftParenthesis', 'Expression', 'RightParenthesis')
    .generate('Expression0', function (values) { return values[1]; }),
get('LeftBracket', 'RightBracket')
    .generate('Array', function (values) { return new ArrayExpression([]); }),
get('LeftBracket', 'ExpressionList', 'RightBracket')
    .generate('Array', function (values) { return new ArrayExpression(values[1]); }),

For each discovered element, the grammar is building an expression, that can be evaluate using a context. A context has the values of the visible variables. Example:

function NameExpression(name) {
    this.evaluate = function (context) {
        var value = context.getValue(name);
        if (typeof value == 'function')
            return value();
        return value;
    this.getName = function () { return name; };
    this.setValue = function (context, value) {
        context.setLocalValue(name, value);

function InstanceVariableExpression(name) {
    this.evaluate = function (context) {
        if (!context.$self.$vars)
            return null;
        return context.$self.$vars[name];
    this.getName = function () { return name; };
    this.setValue = function (context, value) {
        if (!context.$self.$vars)
            context.$self.$vars = { };
        context.$self.$vars[name] = value;

function ClassVariableExpression(name) {
    this.evaluate = function (context) {
        if (!context.$self.$class.$vars)
            return null;
        return context.$self.$class.$vars[name];
    this.getName = function () { return name; };
    this.setValue = function (context, value) {
        if (!context.$self.$class.$vars)
            context.$self.$class.$vars = { };
        context.$self.$class.$vars[name] = value;

function ConstantExpression(value) {
    this.evaluate = function () {
        return value;

I have access to JavaScript features from Ruby, example, a test:

exports['Evaluate JavaScript global name'] = function (test) {
    global.myglobal = 42;
    var context = contexts.createContext();
    var parser = parsers.createParser("js.myglobal");
    //parser.options({ log: true });
    var expr = parser.parse("Expression");
    var result = expr.value.evaluate(context);
    test.equal(result, 42);

The js namespaces allowed the access to JavaScript defined variables, and all its ecosystem, at the browser or at the server.

I want to share my advances at RubyConf 2014 Argentina.

Next steps: access to Node.js require, web site examples using Node.js/Express, console examples, browser examples, etc.

Stay tuned!

Angel “Java” Lopez

April 3, 2014

New Month’s Resolutions: April 2014

Review of my March’s resolutions:

– Work on DictSharp [complete] see repo
– Give talk about Node.js Distributed Applications [complete] see repo see online slides
– Improve SimpleGammon [complete] see repo
– Improve Annalisa [complete] see repo
– Add @for to Templie [pending]
– Work on PreciosaAnnalisa online web services [complete] see repo
– Improve my Node.js Distributes Applications samples [complete] see repo see repo see repo
– Work on ScalaSharp [complete] see repo
– Improve ClojSharp [complete] see repo
– Improve SimpleAsync, do operation (functions in parallel) [pending]
– Improve Aktores [pending]
– Distributed messages in AjErl [pending]
– Add variable scope to Mass language [pending]
– Start code generation as a service [partial]

Additionally, I worked on:

– Complexo, simple complex numbers operations in JavaScript [complete] see repo
– Started RustScript, a Rust programming language interpreter in JavaScript [complete] see repo
– Continue RuScript, a Ruby interpreter in JavaScript [complete] see repo
– Continue RubySharp, a Ruby interpreter in C# [complete] see repo
– Started AjLispScala, a Lisp interpreter in Scala, using TDD and SBT [complete] see repo
– Recorded a second video Node.js Spanish tutorial [complete] see post

For this new month, my resolutions are:

– Continue AjLispScala
– Continue AjGenesisNode-Express
– Continue AjGenesisNode-PHP
– Continue RuScript
– Continue RustScript
– Distributed Messages in AjErl
– Give a talk Intro to Node.js
– Publish a new Node.js video tutorial

More fun is coming.

Keep tuned!

Angel “Java” Lopez

March 25, 2014

End Of Iteration 2014w12

Filed under: AjGenesis, Code Generation, JavaScript, NodeJs, Ruby, RubySharp, RuScript — ajlopez @ 10:41 am

Previous Post
Next Post

Ruby Interpreters

I updated my projects

The first in a Ruby interpreter in C#. I started to add the support to detect the local variables in an scope. In Ruby, there is the function local_variables() that returns a list of the names of local declared variables (not only the already initialized).

The second project is the seed to my next talk: it implements Ruby in JavaScript, as an interpreter. I added more support for modules and classes, and function declaration with and without arguments and parenthesis. I’m using my grammar/parser generation:

It was updated to support new use cases (dog fooding!).


I added some simple features to

My Rust Programming Language interpreter in JavaScript. Not, it has function definition with arguments, let and let mut (mutable), some new arithmetic, bitwise and logical operators, with precedence. And a powerful assert! to start writing test programs.


I updated

My Scala interpreter in C#. The additions were simple: more node support. A node is the product of a parser, and define a part of the program. It has a type to be checked. That is the main difference with expression: a node has a type that can be inferred from the rest of the program, or by explicit declaration. As a typed language, an Scala interpreter cannot directly evaluate expression. I should check the types of the nodes, and THEN, generate a correct expression tree.

Code generation

I created

A new global tasks to be used by AjGenesis and related tasks to modify the model using command line. I started the new global tasks

to generate code for PHP and Django. There are only the skeletons, but I want to generate code for these languages/frameworks using a free model. Meanwhile, you can check the simple pages generated from:

The next big step: having a code-as-a-service application, written in Node.js, using AjGenesisNode, and deployed on Heroku.

I worked on two non-public projects, too.

More fun is coming!

Keep tuned!

Angel “Java” Lopez

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