CHAPTER 1 WHAT IS TOUCHDEVELOP?

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1 CHAPTER 1 In this chapter we present an overview of how TouchDevelop works within your phone and the larger ecosystem the cloud, the communities you are involved in, and the websites you normally access. We conclude with a brief introduction to the Windows Phone INSTALLING TOUCHDEVELOP QUICK START 1.3. WHY TOUCHDEVELOP? 1.4. IS TOUCHDEVELOP A PROGRAMMING LANGUAGE? 1.5. THE TOUCHDEVELOP ECOSYSTEM 1.6. AN INTRODUCTION TO THE WINDOWS PHONE 1.7. A QUICK QUIZ 1.1. TouchDevelop is a novel application development environment for anyone to script their smartphones anywhere you do not need a separate PC. TouchDevelop allows you to develop Windows Phone applications that can access your data, your media, your sensors, and allows using cloud services including storage, computing, and social networks. TouchDevelop targets students, hobbyists, power users, and developers. TouchDevelop applications are written for fun, for personalizing the phone, and for creating productivity tools. TouchDevelop brings the excitement of the first programmable personal computers to the now ubiquitous mobile devices. Scripts developed using TouchDevelop allow users to engage with personal interests and possessions, by showing and manipulating music and pictures stored on their own mobile device, the sensors of the phone, and the friends in their social networks. 1

2 VERSION 1 TouchDevelop programs are not large (typically less than 100 lines of code), and evolve over time with other users adding to shared scripts. Figure 1.1 (a) below shows a screen shot of TouchDevelop application in the Windows Phone. Figure 1.1(b) shows script listing of a simple program, and (c) depicts execution of a script within the TouchDevelop application. Figure 1.1: Screen shots of (a) TouchDevelop application for Windows Phone (b) code listing of a TouchDevelop program; (c) execution of a script. TouchDevelop can be used to develop games such as missile defense, which is a full featured game where you defend cities against incoming missiles ( Script for this sample game can be downloaded to TouchDevelop application installed on a Windows Phone, and executed or tailored. An example of TouchDevelop scripts being used for productivity is the meet now script, which finds the active online meetings for you and joins it through the Microsoft Lync application installed on your Windows Phone ( You can find numerous TouchDevelop samples on the TouchDevelop site ( This site also hosts scripts shared by other users to learn from, or to adapt INSTALLING TOUCHDEVELOP QUICK START If you are about to use TouchDevelop for the first time on your Windows phone, you will first need to install it. There are two easy ways to proceed, you can use either one. 2

3 Touch the Marketplace tile on the Windows phone, then press the search icon at the bottom of the screen, and type the text touchdevelop into the MARKETPLACE SEARCH menu page which comes us. Before you finish typing all the letters, the TouchDevelop app should appear as a choice on the screen. Touch that choice, and then touch INSTALL. Touch the BING search button at the bottom right of your phone, and type the text touchdevelop into the Bing search window, then touch the right arrow key at the bottom right of the keyboard to cause bing to perform its search. The first hit which comes back from Bing should be TouchDevelop at the URL Touch that selection. The webpage which is displayed has a download button in the top right-hand corner, which you should touch. It looks like the picture below WHY TOUCHDEVELOP? We are in the midst of a revolution in computing technology. In 2011, more touchscreen-based mobile devices like smartphones and tablets were sold than desk-tops, laptops, and netbooks combined. In fact, in many cases incredibly powerful and easy-to-use smart phones are going to be the first, and possibly, the only computing device many of us will own. In addition to touch screens, smart phones are also equipped with sensors such as camera, accelerometers, Global Positioning Systems (GPS), and light detectors, to name a few. Furthermore, we carry smart phones wherever we go, and constantly interact with these devices, making our daily lives more productive and interesting. However, professionally developed mobile apps available on most smart phones through the respective AppStore and Marketplaces restrict end-users to developer defined interactions and scenarios. While these interactions may be useful and interesting to the application developer, these may not be most interesting and useful for all users. TouchDevelop allows any phone user to create customized scripts, easily and in much less time compared to traditional app development models, allowing all end users to address their unique needs. With TouchDevelop, the user does not need to own a personal computer, nor does the user require knowledge into deep programming constructs. Since all development takes place on the smart phone, without the need for a personal computer, a user may program, anywhere and anytime. Finally, TouchDevelop scripts can be shared with other users using the TouchDevelop Script Bazaar IS TOUCHDEVELOP A PROGRAMMING LANGUAGE? TouchDevelop is a language for writing scripts using the TouchDevelop Windows Phone application. This application is also a runtime environment for executing TouchDevelop scripts. The TouchDevelop language is a typed, structured programming language built around the idea of only using a touchscreen as the input device to author code. It has built-in primitives which makes 3

4 VERSION 1 it easy to access the rich sensor data available on a mobile device. The TouchDevelop language mixes imperative, object-oriented, and functional features. The imperative parts are most visible: users can update local variables, and state of global objects. Object-orientation is dictated by auto completion requirements - properties of objects are an easily accessible and intuitive concept. However, for the sake of simplicity, the language itself does not have built-in constructs which would allow users to define new types or properties. A TouchDevelop script consists of a number of actions (procedures) and the global state (global variables). The TouchDevelop script editor is part of the TouchDevelop Windows Phone application designed for efficient entry of scripts using only the touch screen. Further details can be found in Chapter 2. TouchDevelop scripts execute within the TouchDevelop application on Windows Phone. This execution is reactive - actions are run in response to events. Events can be raised by user input (e.g., interacting with a UI element, changing the orientation of the phone, or shaking it), events from the phone (e.g., change of active song in the song player) or passage of time. TouchDevelop uses cooperative multi-threading. Actions and events are executed single-threaded 1.5. THE TOUCHDEVELOP ECOSYSTEM TouchDevelop scripts developed using the TouchDevelop Windows application can be shared with other users using TouchDevelop cloud infrastructure (TouchDevelop.com). Figure 1.2 depicts a high level architectural overview of the TouchDevelop ecosystem. Figure 1.2: TouchDevelop ecosystem, including the community of developers using the Windows Phone, website and cloud infrastructure. 4

5 TouchDevelop scripts are developed by users on their Windows Phones and executed within the TouchDevelop run time environment on the phone. These scripts can be shared with other users. The TouchDevelop cloud infrastructure allows this sharing amongst a community of TouchDevelop users. These scripts can also be searched, viewed, and installed into a user s account using the TouchDevelop website. The cloud infrastructure enables sharing, and, acts as a repository of all scripts developed and published by users. In order to publish scripts developed on the Windows Phone, you will have to sign-in and accept the current TouchDevelop Cloud Services Agreement; please also read the TouchDevelop Privacy Statement. Detailed steps are available in Chapter 2. Once your script is published to the TouchDevelop cloud infrastructure, other TouchDevelop users can view your script in the new section of the website or the app (Figure 1.3). Users can also see author s username used to publish the script from the Windows Phone. Scripts in this list are sorted by the time of publication, with most recently posted scripts on the top. Figure 1.3: Listing of TouchDevelop scripts on touchdevelop.com in three pre-defined orders. The TouchDevelop website allocates a stable unique web address relative to touchdevelop.com for your script which can be used to navigate to the script directly. You can share this link with other people. Following this link leads to a webpage dedicated to the script. This webpage provides further statistics for the script such as the number of users who have installed your script on their phone and the number of runs. This page also lists usernames of TouchDevelop users who have reviewed your script as well as detailed comments. Figure 1.4: TouchDevelop website page for each script 5

6 VERSION 1 Once users like your script, they can review it by giving hearts. The webpage shows the number of user reviews (hearts) given to each script by other users. The website also shows the number of discussion posts on your script started by other users. See Figure 1.4. Users cannot review your scripts or give comments related to your scripts on the TouchDevelop website. These two activities are possible on the phone within the Windows Phone TouchDevelop application. Once a user navigates to your script on the phone, by either searching for it, or finding it in the new, top, or featured lists, a user has the option to either review (by clicking the heart), or provide comments. Figure 1.5: Searching, installing, reviewing and commenting on scripts using the TouchDevelop application on the Windows Phone. The selected script can be installed and executed locally by tapping on the down-pointing arrow at the bottom of the screen. The script page (on the touchdevelop.com website and in the app) may show a previously published script on which the current script is based on. TouchDevelop keeps track of the base scripts when you are editing it. Similarly, this page (on the website and in the app) also displays details for other scripts which are based on the current one. In the following chapters you will learn more about writing TouchDevelop scripts on the Windows Phone. 6

7 Figure 1.6: Forward and backward relationship between current script and other scripts as displayed for all scripts on the script webpage AN INTRODUCTION TO THE WINDOWS PHONE TouchDevelop is a Windows Phone application and can be installed and executed on the Windows Phone versions 7.5, or later. For a quick introduction to the Windows Phone visit the Windows Phone website ( Figure 1.7: Pivot control allowing navigation to multiple screens using the drag gesture.* * 7

8 VERSION 1 Like all smart phones today, Windows Phone supports touch interface allowing TAP (a finger touches the screen and releases), and DRAG (A finger touches the screen and moves in any direction). In addition to these basic gestures, allowing easy navigation, Windows Phone also supports a host of additional gestures. Read the details on MSDN ( All applications on the Windows Phone allow navigation to multiple screens, made possible by using the concept of a PIVOT (see Figure 1.7). Swiping sideways or tapping a different pivot point (for example tapping the word installed in Figure 1.7) changes the pivot point and causes different information to be displayed on the screen A QUICK QUIZ Take this quick quiz to see if you understand the concepts discussed in this chapter. i 1. TouchDevelop s language is a) JavaScript for the phone b) A brand new language especially designed for touchscreen phone use c) A simplified language suitable for teaching, but not for real applications d) Purely object-oriented 2. To use TouchDevelop, you only need a) A Windows phone b) Any mobile phone c) A phone and a computer d) Just a computer 3. TouchDevelop is a) A simple system that does not yet access the phone s sensors or media content b) Fully able to access all media content and sensors of the phone, and the internet c) Only able to access media content on the phone such as songs and pictures d) Not able to access the internet yet 4. Typically, new users can write their first TouchDevelop script using sensors in a) A day b) Half a day c) After a week d) An hour and a half 5. Scripts in TouchDevelop can be shared by 8

9 a) ing them b) Publishing them on the Marketplace c) Saving them on to a computer d) Publishing them on the Bazaar 6. To use the TouchDevelop Bazaar, you need a) A Windows Live ID b) A Windows Live or FaceBook Account c) An AppHub Developer account d) None of the above 7. Scripts in the Script Bazaar can be viewed a) Only on the phone through TouchDevelop b) Only on a browser c) On the phone through TouchDevelop and through a browser d) On TouchDevelop, a browser, and print outs 8. Reviewing and giving comments to scripts is possible a) Only on the phone through TouchDevelop b) Only on a browser c) On the phone through TouchDevelop and through a browser d) Only on Facebook 9. A code such as /aoxd is a a) Part of a stable web address in the Bazaar for a script b) Not relevant for most programmers, and can be ignored c) A checksum for the script to ensure that it is not corrupt on downloading d) A conversion code needed to get a script from the Bazaar to the Marketplace. 10. TouchDevelop is a project from a) Microsoft Windows division b) Researchers and engineers at Microsoft Research c) Academics with a grant from Microsoft Research d) All of the above 9

10 VERSION 1 i Answers: 1. b) 2. a) 3. b) 4. d) 5. d) 6. b) 7. c) 10

11 8. a) 9. a) 10. b) 11