Rahul Sharma (Editor)

Snap! (programming language)

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Developer
  
Jens Mönig

Typing discipline
  
dynamic

Snap! (programming language)

Paradigm
  
object-oriented, educational, event-driven

Designed by
  
Brian Harvey and Jens Mönig

First appeared
  
2011; 6 years ago (2011)

Stable release
  
4.0.2 / August 6, 2015; 19 months ago (2015-08-06)

Snap! is a free, blocks- and browser-based educational graphical programming language that allows students to create interactive animations, games, stories, and more, while learning about mathematical and computational ideas. Snap! was inspired by Scratch, but also targets both novice and more advanced students by including and expanding Scratch's features.

Contents

Snap! 4.0 is entirely browser-based with no software that needs to be installed on the local device.

History

Snap! 4.0 and its predecessor BYOB were developed by Jens Mönig for Linux, OS X or Windows, with design ideas and documentation provided by Brian Harvey from University of California, Berkeley and have been used to teach "The Beauty and Joy of Computing" introductory course in computer science (CS) for non-CS-major students. As of December 2014, 100 New York City (NYC) high schools will introduce University of California at Berkeley’s “Beauty and Joy of Computing” as a new AP Computer Science Principles course in 2015, using Snap!.

Earlier, desktop-based 3.x version's open-source code is available under a license that allows modifying for non-commercial uses and can be downloaded from the UC Berkeley website or CNET's Download.com and TechTracker download page. The source code is Affero General Public License (AGPL) licensed and is available for download within Snap! itself and on Github.

Platforms

Snap! 4.0 runs on iOS, OS X, Windows, and Linux devices, because it is implemented in JavaScript using an HTML5 Canvas application programming interface (API). In contrast, Scratch 2.0 was written in Adobe Flash, so it cannot run on Linux without Adobe Air.

Recognition

Snap! has been recognized by the Logo Foundation, and reviewed in an online magazine for programmers.

User interface

The screen areas are arranged in the way they used to be in Scratch prior to the version 2.0, with the blocks palette in the left area, the scripts area associated with a selected sprite in the middle of the screen, and the stage area with sprites thumbnails listed below it in the right area of the screen.

The "stage area" is featuring the results (i.e. animations, turtle graphics etc., everything either in small or normal size, full-screen also available). Below it are listed all available sprites' thumbnails.

With a sprite thumbnail selected, blocks of commands can be applied to it by dragging them from the Blocks Palette onto the middle area of the screen, containing all the scripts associated with the selected sprite. Available blocks are listed and categorized in the Motion, Looks, Sound, Pen, Control, Sensing, Operators, and Variables groups as shown in the table below. Each can also be individually tested under different conditions and parameters via double-click.

Besides the Script tab, there are two other tabs, the Costumes tab and the Sounds tab. An expandable bar at the right is Help area.

Features

The most important features which differentiate it from Scratch as following:

  • First class functions or procedures (their mathematical foundations are called also "Lambda calculus"),
  • first class lists (including lists of lists),
  • First class sprites (in other words prototype-oriented instance-based classless programming),
  • Nestable sprites
  • Codification of Snap! programs to mainstream languages such as Python, JavaScript, C, etc.
  • References

    Snap! (programming language) Wikipedia