The Joo Programming Language

Arduino UNO

Joo is a programming language created to run on machines with extremely low resources like microcontrollers.I had this idea while playing around with the <a href="https://github.com/JohnsProject/Arduios">Arduios </a>and <a href="https://github.com/JohnsProject/Retruino">Retruino,</a> the arduios has a lot of potential on it's own but I just wanted more. And this project is the result of that.I've developed the first functional version of it as a weekend hack a while ago, so there's quite a lot to do as it has a lot of potential and the compiler and virtual machine code could be a lot better.Since the code wasn't that good I wanted to refactore it before publishing, the new code is in the <code >refactoring</code> branch, but there's just so much to do that I decided to publish it as it is, because as I already said it has a lot of potential and if I publish it maybe a community will grow and it will be developed faster and in ways I can't even dream about right now!<h3 >Using the Joo SDK</h3>To start download the SDK at <code >builds/JooSDK.jar</code>, then create a new file called <code >Test.joo</code> in the same folder as the SDK file and paste the code below.<pre ><code >include int helloWorld = 10 function Start\t call Print helloWorld endFunction </code></pre>Then execute it using the <code >joo</code> command.<figure><img src=https://projects.arduinocontent.cc/36aa7c18-69e6-4c30-92d1-6d6317474ca0.PNG /><figcaption> </figcaption></figure>The commands supported are<ul ><li ><code >joo <file></code> If the specified file is a <code >.cjoo</code> file, executes the code. If the file is a <code >.joo</code> file compiles it then executes it.</li></ul><ul ><li ><code >joo -compile <file></code> Compiles the <code >.joo</code> file, and generates a <code >.cjoo</code> file in the same folder.</li></ul><ul ><li ><code >joo -create <file></code> Creates a <code >.joo</code> file at the specified path with the Joo template code.</li></ul><ul ><li ><code >joo -help</code> Shows the Joo SDK help message.</li></ul><h3 >Programming the Arduino UNO with Joo</h3><a href="https://github.com/JohnsProject/Arduios">Arduios </a>allows you to use a sketch in different use cases, without having to upload a new one every time. But joo is on a whole new level, you just need to upload the ArduinoJooVM once, then you can upload any joo binary using the serial port of the arduino and the vm will execute it.You're probably thinking, how does it work? The Arduino UNO only has 2KB of ram. Well, that's where the magic happens, if you wan't to understant how it works, read <a href="https://github.com/JohnsProject/Joo#the-joo-byte-code-language">The Joo byte code language.</a>To start upload the ArduinoJooVM sketch at <code >builds/ArduinoJooVM/ArduinoJooVM.ino</code>. After uploading open the serial monitor and copy the byte code in the <code >Test.cjoo</code> file created in <a href="https://github.com/JohnsProject/Joo#using-the-joo-sdk">Using the Joo SDK </a>and send it.<figure><img src=https://projects.arduinocontent.cc/e4e37cb1-5264-49c0-8d50-856ef275a0e9.PNG /><figcaption> </figcaption></figure><h3 >The Joo programming language</h3>Is a clean, fast, static typed, general purpose language.Code files are saved as <code >.joo</code> files that get compiled to <code >.cjoo</code> files.Comments look like this<pre ><code ># this is a single line comment ## this is a multi-line comment ## </code></pre>Right now 4 data types are supported <code >int</code>, <code >fixed</code> (fixed point 8.8 bytes), <code >bool</code> and <code >char</code>. I'm planning to add <code >string</code> someday. I implemented fixed point instead of floating point for performance reasons.<pre ><code >int myInt # it's not necessary to assign a value int myIntWithValue = 50 fixed myFixed = 12.34 bool myBool = true/false 1/0 char myChar = 'A' </code></pre>A <code >constant</code> is a value that can't be changed, it doesn't have a type, the compiler just replaces it's name with it's value at compile time.<pre ><code >constant MY_CONSTANT = 10 int myInt = MY_CONSTANT </code></pre>The <code >include</code> keyword allows to add code from other <code >.joo</code> files in the same directory or subdirectories using their name. The compiler just adds the code of the file to the end of the code in the current file.<pre ><code >include include Directory/MyLibrary.joo </code></pre>Every code, except for variable and constant declarations and includes, needs to be inside a <code >function</code>, at the moment the first function in the code is the one the virtual machine calls to start executing. Functions can have up to 6 parameters.<pre ><code >int myInt bool myBool function Start\t # executes MyFunction with the specified arguments\t call MyFunction myInt myBool # restarts the execution of the function repeatFunction endFunction function MyFunction int _myInt bool _myBool\t # write code here endFunction </code></pre>All 4 supported data types can also be used as a array. The max length of array is <code >54</code>.<pre ><code >int:10 myArray # declares a array with size 10 function Start\t myArray:5 = 25 # assigns the value 25 to the 5th index of the array. endFunction </code></pre>Conditions are also supported with the <code >if</code>, <code >elseIf</code> and <code >else</code> keywords.<pre ><code >int firstValue = 10 int secondValue = 5 function Start\t if firstValue == secondValue\t\t # code goes here\t elseIf firstValue == 8\t\t # code goes here\t else\t\t # code goes here\t endIf endFunction </code></pre>Only binary operators are supported, means you need 2 variables, the same variable in both sides of the operator or a value after the operator.<pre ><code >myInt + 5 myInt1 + myInt2 myInt1 -= myInt1 </code></pre>The operators implemented in the standart library are<pre ><code >operator <= int|fixed \t\t\t\t# smaller-equals comparator operator >= int|fixed \t\t\t\t# bigger-equals comparator operator < int|fixed \t\t\t\t# smaller comparator operator > int|fixed \t\t\t\t# bigger comparator operator == int|fixed|bool|char \t\t# equals comparator operator != int|fixed|bool|char \t\t# not equals comparator operator = int|fixed|bool|char \t\t# assign operator operator =+ int|fixed|bool \t\t\t# positive assign operator operator =- int|fixed|bool \t\t\t# negative assign operator operator =! int|fixed|bool \t\t\t# invert assign operator operator + int|fixed \t\t\t\t# add operator operator - int|fixed \t\t\t\t# subtract operator operator * int|fixed \t\t\t\t# multiply operator operator / int|fixed \t\t\t\t# divide operator operator % int \t\t\t\t# modulus operator operator & int \t\t\t\t# bitwise AND operator operator ^ int \t\t\t\t# bitwise XOR operator operator | int \t\t\t\t# bitwise OR operator operator ~ int \t\t\t\t# bitwise NOT operator operator << int \t\t\t\t# bit shift left operator operator >> int \t\t\t\t# bit shift right operator </code></pre>It's possible to declare custom operators and native functions. Native functions are functions that are implemented in the virtual machine, so it allows you to call native code from joo as well as change the value of the variables passed as arguments. At the moment if you have custom operators or native functions you have to modify the vm and recompile it so you can execute your stuff.<pre ><code ># The supported types are separated with a | operator == int|fixed|bool|char operator += int|fixed native HelloWorld int|fixed bool int|char # native functions are called like other functions call HelloWorld myInt myBool myInt </code></pre>The joo programming laguage has a standart library, even if very bare bones right now, it has common used operators and native functions that are already implemented in the default build of the virtual machine.You can include the standart library using<pre ><code >include StandartLibrary.joo </code></pre><h3 >Known limitations</h3>Most of the limitations are a result of the extremely efficient byte code.<ul ><li >64 variables + functions</li></ul><ul ><li >6 parameters/function</li></ul><ul ><li >54 max array size</li></ul><ul ><li >Function call arguments must be variables.</li></ul><ul ><li >Number type variable declaration doesn't support negative values.</li></ul>Well, you know, i'm lazy and don't exactly know how to explain things, specialy since i've never created a programming language before and there's so much to explain, so take a look at the test code at <code >src/test/resources</code> as well as the compiler and virtual machine code. It will help you get a better understanding of the language and how the magic happens.<h3 >The Joo byte code language</h3>The joo byte code language uses single characters/bytes in the range <code >0 - 127</code> to represent the compiled code executed by the virtual machine.<pre ><code >* 0 - 0\t\tend of file * 1 - 65 \tvariable and function names * 66 - 72 \tparameter names * 73 - 127 \tarray indices * 91 - 127 \tnumbers, keywords and types * 1 - 127 \toperators, native functions </code></pre>So let's say you have this code<pre ><code >int myInt bool myBool function Start\t myInt = 10\t myBool = true\t call MyFunction myBool myInt endFunction function MyFunction bool _testBool int _testInt _testBool = false\t _testInt = 5 endFunction </code></pre>Since in byte code the names of the variables and functions a.k.a components are represented in as 1 number in the range <code >1 - 65</code> the byte code the names are<ul ><li ><code >myInt</code> = 1</li></ul><ul ><li ><code >myBool</code> = 2</li></ul><ul ><li ><code >Start</code> = 3</li></ul><ul ><li ><code >MyFunction</code> = 4</li></ul>The <code >MyFunction</code> parameter names are<ul ><li ><code >_testBool</code> = 66</li></ul><ul ><li ><code >_testInt</code> = 67</li></ul>so the byte code of the code above looks like<pre ><code >int 1 bool 2 function 3 1 = 10 2 = true call 4 2 1 endFunction function 4 66 = false 67 = 5 endFunction </code></pre>Of course the keywords are also replaced by their single byte representation. The <code >MyFunction</code> parameters don't need to be declared in the byte code since the type and parameter count checks happen at compile time.Pretty smart isn't it? *guy taping head meme*<h3 >The Joo virtual machine</h3>The language can be easily extended with <code >operator</code> and <code >native</code> function libraries. But their functionality needs to be implemented in the virtual machine.<h3 >Custom operators</h3>To create a custom operator, first of all you need to declare it in joo code<pre ><code >operator += int|fixed </code></pre>And then you need to implement it in the virtual machine<figure><img src=https://projects.arduinocontent.cc/f9b3fed7-e36b-4975-b861-11719495252e.PNG /><figcaption> </figcaption></figure>This will only work if you include the standart library as you're continuing the operator names of it, otherwise you need to write<pre ><code >#define OPERATOR_MY_OPERATOR 0 + OPERATORS_START </code></pre>Then just reupload the sketch or recompile the virtual machine and the operator can already be used in code.<pre ><code >include operator += int|fixed int myInt = 10 function Start myInt += 5 endFunction </code></pre><h3 >Custom native functions</h3>It's the same process as for the operator, declare it in joo code<pre ><code >native MyFunction int char </code></pre>And the implement it in the virtual machine<figure><img src=https://projects.arduinocontent.cc/3e70f09a-1d64-4d5b-a861-68ec22548253.PNG /><figcaption> </figcaption></figure>Then just reupload the sketch or recompile the virtual machine and the native function can already be used in code.<pre ><code >include native MyFunction int char int myInt char myChar = 'A' function Start call MyFunction myInt myChar endFunction </code></pre>

The Joo Programming Language

It's a language that allows the arduino to change programs at runtime, without having to reupload a sketch to it.