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
- v0.0.5: 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!
Turtle Graphics v0.0.6 New Features
This Commit has the following changes:
- Add MoveTo function
- Add Circle function
- Add Turning (absolute degree)
- Set Screen Color
- Enhanced Error/Warning handling
LogoTurtle Screenshots
Let’s put all the above in one LOGO source code to demonstrate:
ht cs screen green color yellow ; test comment pu moveto -200 20 pd turn 270 repeat 8 [circle 50 fd 10 rt 45]
Javascript Parses Logo Source Code with 2 Parameters
The MoveTo takes two parameters that moves the turtle to a given coordinate, which is handled by the following javascript.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 | case "moveto": expr = this.evalVars(word_next); try { word_next = eval(expr); } catch (e) { this.pushErr(word, LOGO_ERR_EVAL, expr); return false; } if ((word_next == '') || (!isNumeric(word_next))) { this.pushErr(word, LOGO_ERR_MISSING_NUMBERS, word_next); return false; } second_word = getNextWord(s, y.next, U); second_word_word = second_word.word; expr = this.evalVars(second_word_word); try { second_word_word = eval(expr); } catch (e) { this.pushErr(word, LOGO_ERR_EVAL, expr); return false; } if ((second_word_word == '') || (!isNumeric(second_word_word))) { this.pushErr(word, LOGO_ERR_MISSING_NUMBERS, second_word_word); return false; } this.logo.moveTo(word_next, second_word_word); i = second_word.next; break; |
case "moveto": expr = this.evalVars(word_next); try { word_next = eval(expr); } catch (e) { this.pushErr(word, LOGO_ERR_EVAL, expr); return false; } if ((word_next == '') || (!isNumeric(word_next))) { this.pushErr(word, LOGO_ERR_MISSING_NUMBERS, word_next); return false; } second_word = getNextWord(s, y.next, U); second_word_word = second_word.word; expr = this.evalVars(second_word_word); try { second_word_word = eval(expr); } catch (e) { this.pushErr(word, LOGO_ERR_EVAL, expr); return false; } if ((second_word_word == '') || (!isNumeric(second_word_word))) { this.pushErr(word, LOGO_ERR_MISSING_NUMBERS, second_word_word); return false; } this.logo.moveTo(word_next, second_word_word); i = second_word.next; break;
Roadmap of Chrome Extension: Logo Turtle
- Add Functions
- Add IF/THEN/ELSE
- Add Variables
- Add Colors
- Add MoveTo
- Add PrintText
- Add Circle
- Add Arc
- Add Eraser
- Add Fill
- Save As Picture
- Save As Program
- Comments
- Add Recursion Support
- Add Global/Local Scopes
- etc. etc.
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) —
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