Turtle Programming: Fractal Stars, Random, Console, Eraser, SetPC, SetXY, Examples, Wait, Bug Fixes and So much more!

Introduction to Logo Turtle

LogoTurtle is currently the FIRST and only one Chrome Extension for Turtle Graphics. I have also written a PHP version of Logo Interpreter in 2006 but that runs only on the server.

Previous Contributions

• v0.0.9: Turtle Programming v0.0.9: Add SetX, SetY, Square and Rect!
• v0.0.8: Turtle Programming v0.0.8: /* */ comments, dotxy, and javascript!
• v0.0.7: Turtle Programming v0.0.7: Functions with Parameters + Recursion!
• v0.0.6: Turtle Programming v0.0.6: Adding Circle, MoveTo, Turn and Screen!
• v0.0.5: Turtle Programming v0.0.5: Adding IF/ELSE and STOP!
• v0.0.4: LogoTurtle: Make Variables and Comments
• v0.0.3: Turtle Graphics Programming Update: Adding text, jump, dot, fontsize, download as png
• v0.0.2: LogoTurtle v0.0.2: ShowTurtle, HideTurtle, Color, Width and Help.
• v0.0.1: Teach Your Kids Programming – The First Logo Interpreter (Turtle Graphics) in Chrome Extension!

Logo Turtle v0.0.10 New Features

This Commit has the following changes:

• Add global :RANDOM variable that returns from 0 to 1.
• Add Wait which sleeps milliseconds.
• Bug Fixes so that Procedures can take more than 1 parameter.
• Eraser mode that could be turned on via pe and turned off via ppt.
• SetPC to set color from a defined color table (compatible with standard LOGO source code).
• Console prints text/variables to console.
• Allow Text to evaluate the variables.
• SetXY is alias of MoveTo (SetXY is standard LOGO keyword).
• Examples in Help Tab.
• Fix (0 == ” true problem) in Javascript

.

LogoTurtle Source code and Screenshots

Sum up integers from 1 to 100. Print it to console and text it out (turtle can write) on screen. This calculates sum from 1 to 100 and prints to console (Chrome Browser), log, and draw a text.

ht cs make "sum 0
make "i 1
repeat 100 [
  make "sum :sum+:i
  make "i :i+1
]
console [sum is :sum] ' debuggingconsole and log tab
text [sum is :sum] ' print out to screen (turtle writes text)

logoturtle-draws-text-calculates-sum

Drawing a chessboard.

ht cs TO FK :B
  HT # hide the turtle
  IF :B>15 [STOP]
  REPEAT 4 [FD :B RT 90]
  FK :B+1 # draw a bigger square to fill
END

TO QP :Y
  IF :Y>4 [STOP]
  REPEAT 4 [FK 15 FD 15 FK 1 FD 15]
  RT 90 FD 30 RT 90
  REPEAT 4 [FK 15 FD 15 FK 1 FD 15]
  RT 180
  QP :Y+1
END

QP 1

logoturtle-chessboard

Fractal Stars:

cs ht
to star :size :small
    if :size<:small [stop]
    repeat 5 [fd :size star :size*0.3 :small rt 144]
end
jump -100
star 150 10

logo-turtle-programming-fractal-stars

:RANDOM variable returns random number between 0 and 1.

cs ht repeat 1000 [fd 4 rt :random*360]

logo-programming-random-drawing

with random coloring using old-fashion setpc that takes a color index from 1 to 15.

cs ht repeat 1000 [fd :random*15 rt :random*360 setpc :random*15]

logo-turtle-programming-random-color

Console Function in Logo implemented in Javascript

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case "console":
    let cur_console_text, result;
    if (word_next != '[') {
        word_next = this.evalVars(word_next);                   
        result = word_next;         
        if (this.console) {                     
            cur_console_text = this.console.val();
            this.console.val(cur_console_text + "\n" + result);
        }
        console.log(result);
        i = y.next;                     
    } else {
        find_next_body = getNextBody(s, i, U);
        if (find_next_body.right >= U) {
            this.pushErr(word, LOGO_ERR_MISSING_RIGHT);
            return false;
        }
        result = this.evalVars(s.substring(find_next_body.left + 1, find_next_body.right));                 
        if (this.console) {                     
            cur_console_text = this.console.val();
            this.console.val(cur_console_text + "\n" + result);
        }
        console.log(result);                        
        i = find_next_body.right + 1;                       
    }
    break;  

case "console":
    let cur_console_text, result;
    if (word_next != '[') {
        word_next = this.evalVars(word_next);                   
        result = word_next;         
        if (this.console) {                     
            cur_console_text = this.console.val();
            this.console.val(cur_console_text + "\n" + result);
        }
        console.log(result);
        i = y.next;                     
    } else {
        find_next_body = getNextBody(s, i, U);
        if (find_next_body.right >= U) {
            this.pushErr(word, LOGO_ERR_MISSING_RIGHT);
            return false;
        }
        result = this.evalVars(s.substring(find_next_body.left + 1, find_next_body.right));                 
        if (this.console) {                     
            cur_console_text = this.console.val();
            this.console.val(cur_console_text + "\n" + result);
        }
        console.log(result);                        
        i = find_next_body.right + 1;                       
    }
    break;  

Roadmap of Chrome Extension: Logo Turtle

I believe LogoTurtle is more or less in beta now. Therefore, bug Fixes and any suggestions, please shout @justyy

Technology Stack

If an App can be written in Javascript, eventually it will be written in Javascript.

Chrome Webstore

Install the Turtle Programming for Kids Now!

Contribution Welcome

Github: https://github.com/DoctorLai/LogoTurtle

• Fork it!
• Create your feature branch: git checkout -b my-new-feature
• Commit your changes: git commit -am ‘Add some feature’
• Push to the branch: git push origin my-new-feature
• Submit a pull request.

–EOF (The Ultimate Computing & Technology Blog) —