#bootstrap world

Pyret is a programming language for beginners. In many ways, Pyret shares the same goals as Racket. More specifically, Pyret shares a similar look and feel (in terms of development environment) to WeScheme. Bootstrap World, the team behind WeScheme, is adopting Pyret as the language for their Bootstrap II curriculum. Since I am such a fan of Bootstrap World and hope to use their curriculum this upcoming school year, I thought I would look into Pyret.

I began programming in earnest yesterday. I decided to make a tool that graphs a user generated function. I finished the tool yesterday evening. Today, I was able to turn the tool into a module that anybody could import and use. It is a simple tool; one that required far less work than I anticipated. The hardest part is wrapping my head around functional programming concepts like map and fold. The mailing list was fast and friendly. I could not have done this without their help.

So if you are interested, here is a sample program. All a user needs to do is copy the “import” statement at the top and the “P.make-graph” statement at the bottom. The user then writes the function they want to graph, and then pass that function to the “P.make-graph” function. If you want to see the code that creates the graph, click here. It is not a perfect tool. For instance, graphing the square root of X throws an error message because it will use negative numbers. The graph is also comprised of dots not lines, so some graphs are not as easy to read as others. Finally, (though I am sure there are other areas that need improvement) only the numbers from -50 to 50 (using 0.1 increments) are used as the domain of the function graphed.

I am attending a professional development workshop hosted by the Bootstrap World project. I am having fun and learning a lot. To be honest, the programming requirements really are not all that difficult for the instructor. They have done a nice job in abstracting away some of the issues a beginner will encounter. This, of course, is to be expected. Bootstrap is, after all, a methodical approach to algebra through computers. This is not to say that Bootstrap has no relevance to programming in general or Racket in particular. I would like to touch on touch on a couple of things that stood out.

Circles of Evaluation

Circles of evaluation are a spacial, visual tool for students to understand the composition of functions. This tool also aids in the writing of Racket code. Here is an example of a circle of evaluation: 

The idea is to put the function on the top of the circle. Then the arguments for the function go below, respecting the order. If you have an order of operations problem, then you will have nested circles of evaluations. Use one circle of evaluation for each function used. When you convert these circles to Racket code, imagine an ant crawling from outside the circle across it. When you go into a circle, type an “(“. Then write the function located at the top of the circle. Move to the bottom. Copy what you see, going from left to right. If you see another circle, then repeat the process. When you exit a circle, type a “)”. Circles 1 and 2 above converts to the following Racket code:

(ellipse 30 (+ 20 30) “outline” “red”)

(image-width (rectangle 65 16 “outline” “blue”))

For me, the real value of the circles of evaluation is that it gives students a tool by which to break down the code. Students will often forget a parentheses. There are lots of them, and often you have several in a row. It is easy to get mixed up. When students see the compiler error message, they see the line number of the “(“ that has no “)”. Often, students add the “)” on the same line as given by the error message. This  “cuts off” the function body from the line of code that defines the function name and arguments. This leads to more error messages. What the students need to do is go through the function code to determine where the missing “)” goes. They do not like this, and often do not where to start. By asking them to convert the function to the circles of evaluation, the students will have a tool to figure out where and how many parentheses the function needs. As students progress, they will rely on the circles of evaluation less and less. Eventually, they will not need them at all, but they are a great place to start.

The Design Recipe

The design recipe is a methodology for converting word problems into instructive examples (see below) and ultimately the function that solves the word problem. The first step of the design recipe is to develop a contract (type signature) for the function based upon the word problem. Then, you write a purpose statement. I found that including as many details as possible in the purpose statement helps you write the design recipe. Then you write two examples (see below). You then  look at what changes in the examples, circle it, and label it. This becomes your variable for the function. Finally, you write the function. The design recipe is one of the concepts mentioned again and again during the training. Emphasis was put on every minute detail. Then you were encouraged to have your students “battle” each other. This comes down to having one student quiz one another by asking where did they get the information to write part of their function. The idea is that the design recipe is so thorough that students do not need to see the word problem; everything they need is in the contract, purpose statement, and examples. The design recipe becomes a methodology for writing and testing functions.

The Example Function

In Bootstrap, writing examples is a part of the design recipe. I assumed that, like the contract and the purpose statement, the examples took the form of comments. Coders would look at the examples and do the mental calculations to make sure everything works out. This is not the case. The example function is an abstraction of Racket’s check-expect function. That is, example or check-expect take the user defined function and compares the answer using arguments from an already supplied correct response. One could argue that the check-expect function is more aptly named, thus easier to understand function. To me, though, check-expect is something you do only to verify your functions. Check-expect only passes or fails the function; it is not a teaching tool. Bootstrap, however, uses the name example. Already, example has connotations of being useful/helpful and a tool in creating not just check our work. The two examples mandated by the design recipe serve to isolate the values that change (i.e. the variable(s), something with which students initially struggle). The example function is dual purpose; it checks the validity of the function, and helps students create the proper function. It may seem that I am making too much out of a simple name change, but beginners sometimes need seemingly insignificant changes such as this.

Student Autonomy

  This arrived yesterday, and I am excited for my summer reading this year. I made the decision to move away from Khan Academy and JavaScript. I will actually be starting with Bootstrap World. Despite all of the rhetoric from Silicon Valley and education technology leaders, coding is not the new literacy, and not every student has to learn to code. Programming classes are required at my school, and I feel that it is my duty to make sure that everybody gets something out of the class. Some may love it, other may like the creativity, and some still may not care for coding. Bootstrap has shown that students who code with a functional language transfer this knowledge over to Algebra. So by going with Bootstrap/Racket all of my students get the benefit of an introduction to Algebra. If they happen to like programming, then so much the better.

In my previous posts that outlined some of the work done in coding and education, I did not mention Racket/WeScheme/Bootstrap World. It was not that I was unaware of the work. I watched this video many months ago. I was drawn to the video because “functional reactive programming” is in the title. This was something that caught my eye as I researched the Elm language. Toward the end of the video, Shriam talked about Scheme/Racket as the language of choice. I don’t know much about programming languages, but I do know that Lisp (Racket and Scheme are in the same family) is an old language. I surmised that they have to be out of date and irrelevant to the new programmer. Besides, who wants to deal with all of those parentheses. I was more interested in the value of functional reactive programming, and the video served to justify my choice in Elm for my capstone project.

As my project is coming to a close, I am spending more time thinking about what I have learned. I am not so confident in Elm’s ability to fulfill my needs. That is not to say Elm is a bad language. I find that learning HTML, CSS, and the JavaScript framework du jour to program for the Web is needlessly complex. In that regard, Elm is quite useful; it simplifies the whole process by needing only to write in Elm. This would be a great starting point for new programmers looking to code for the web. However, I am still getting used to functional programming. Some of the concepts I understand, others no so much. Then there are the signals. Signals are vital to Elm. Like functional programming, I only understand a few signals. Other signals are still out of reach, and this leaves my programs lacking functionality. As such, I could not use Elm as an effective teaching tool today. I should also state that Elm is a young language and I am still new to functional reactive programming. I will continue to learn, and I hope that Elm will develop better documentation and tutorials to help beginners such as myself.

Part of the problem is that I am approaching the language as an educator. When I look at the computers in the lab, I see twenty locked down machines. Fortunately, I have admin privileges and can install whatever I want on the machines. Not all labs are like this. Elm has a wonderful playground for new users. There is nothing to install. Any computer lab can access this site. Students can use the language at home or at school. There are no USB keys to lose or forget as students bring their work home and back to school. I found using the Try Elm site was a joy. There is no need to switch between text editor, the command line, and a browser showing the local host. While the playground is just a place to try out the language, I spent a majority of my time coding with it rather than the “official” text editor + elm-reactor in the terminal + browser method. I only moved away from Try Elm when I needed custom buttons and graphics. Sometimes I still use Try Elm and ignore the invalid image icons. For me, the best coding experience for using Elm is this site. However, the site is only for trying the language. You cannot save your work. You cannot share your work. Users are encouraged to code with the more cumbersome text editor and browser method. Having a website that allows you to code, save, and share is a useful tool. In some cases, it is a necessity when the computers are locked down. I would like to see Elm have these same features.

Another issue that I encountered with Elm is the documentation. To be fair, the documentation is quite good. There is a handy search feature to sort through how to do things with Elm. There is a central collection of user created libraries. There are plenty of examples, syntax reference, videos, and, most importantly, friendly and helpful users on the Elm mailing list. As I stated in a previous post, if not for the mailing list, I would not have been able to complete this project. The Elm website has a FAQ that tries to explain the language to those users who come from a JavaScript or Haskell background. Missing from this page is an explanation for those users who come to the language with little to no coding experience. I needed material aimed at beginners. I needed something to read, reread, and then play with the examples until I finally start to understand. I need something that doesn’t read like a dry textbook. Elm, as of now, does not have this.

All of this leads me back to Racket/Scheme. These languages still offer all of the benefits of functional reactive programming, but with a, hopefully, an easier learning curve. Racket/Scheme has a history of being an entry point for new programmers. It has been used in college classes, and with middle school students. Another great selling point is WeScheme, a complete online version of Racket/Scheme. With a Google account, students can code, save, and share. WeScheme can even look at your Google Drive account for images you want to use for programming. Racket, a near offline equivalent to WeScheme, has a beginner mode that simplifies the error messages to more applicable and more easily understood. Bad error messages are a major factor in shaping how I created my program. I want to avoid them at all costs, and that is why my program provides prewritten code.

For my money, the most compelling reason to use Racket/Scheme is their pedagogical track record. Racket was designed to be a teaching tool, and WeScheme moved the language to the cloud. Computer scientists and educators, not coders with VC money, put forth the time to create a language and pedagogical materials. Bootstrap World is a repository for students, teachers, or anyone looking to begin programming. The organization provides student lessons and teacher manuals to help individuals get a programming initiative off of the ground. Matthias Felleisen, the creator of Racket, enlisted some of his freshmen students to write Realm of Racket, a book that taught fellow students how to begin programming. It is not a textbook, but rather an illustrated story that teaches the reader how to program using games, something I tried to incorporate into my capstone project. All of the programs in Realm of Racket are included with the Racket download, so you can start playing with and modifying already functioning code. Again, I took a similar approach with my capstone. As an educator, it is hard to ignore this: Research on the work of Bootstrap World shows that the ideas behind functional programming transfer over to algebra. The Bootstrap World curriculum also aligns with Common Core, if that sort of thing floats your boat. I could go on, but if you are interested in Bootstrap World, take a look/listen to the latest episode of Triangulation. Bootstrap World founder Emmanuel Schanzer talks about his experiences as a programmer and educator, and how that lead to the creation of Bootstrap World.