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diff --git a/tour.md b/tour.md index 6a100ea..5557042 100644 --- a/tour.md +++ b/tour.md @@ -21,7 +21,7 @@ You will need the following to build Teliva: * Some fluency in typing commands at the terminal and interpreting their output. -## Task 1: getting started +## Task 1: running a Teliva app Read the first question in [the Readme](https://github.com/akkartik/teliva/blob/main/README.md). Try running the commands to download and build Teliva. If you have any trouble @@ -39,20 +39,73 @@ number on screen. Hit `enter`. The number increments by 1. Hit `ctrl-x` to exit (press `ctrl` and `x` on your keyboard at the same time). Try editing the app by hitting `ctrl-e`. You see a "big picture" view of the -app. Can you figure out how to modify this app to increment by 2 each time you -hit `enter`? Don't be afraid to experiment. The menu at the bottom always -shows the hotkeys available to you at any point in time. Don't worry, +app. Spend a few moments scanning this page. All programs consist of data and +_functions_: code that operates on data in some way. Teliva apps always start +by running the special function `main`. + +Try browsing to some of the names visible on screen. Don't be afraid to +experiment. The menu at the bottom always shows the hotkeys available to you +at any point in time. Don't worry, everything you do can be undone. + +## Task 2: modifying a Teliva app + +The [first section of the Lua book](https://www.lua.org/pil/1.html) starts +with this one-line example: + +```lua +print("Hello World") +``` + +Can you figure out where to add this line to the app's code so it's visible +when the app runs? + +Start by looking inside `main`. Most Teliva apps tend to share a basic +structure in `main`: +- some initialization, followed by +- a loop that repeatedly updates the screen and then waits for the user to + press a key + +Can you map the lines of `main` to this structure? Which function describes +how the app updates the screen? + +Some hints: +- The function responsible for updating the screen is `render`. +- `render` begins by clearing the screen (`window` in Teliva). + +After you make a change, can you figure out how to run your program? + +Does it do what you expect? Feel free to edit your programs as often as +necessary. Programming is just long sessions of repeatedly editing (`ctrl-e`) +and running (`ctrl-e`) your program. + +Once you're happy with your change, try exiting Teliva and restarting it with +the same app. Do you still see your changes? + +You could save the file `counter.tlv` anywhere you like at this point. Or +share it with someone else. Everything needed for the app is in that file.` If +you get stuck or have a question, [send it to me!](http://akkartik.name/contact) + +## Task 3: variables and arithmetic + +Can you figure out how to modify this app to increment by 2 each time you +hit `enter`? Again, don't be afraid to experiment. The menu at the bottom +always shows the hotkeys available to you at any point in time. Don't worry, everything you do can be undone. -Check out some of the short sections from [the Lua book](https://www.lua.org/pil/contents.html): -[getting started](https://www.lua.org/pil/1.html); [assignment](https://www.lua.org/pil/4.1.html); -[what you can do with numbers](https://www.lua.org/pil/3.1.html). +Divide the problem into two parts in your head: where to make your change and +what change to make there. You've already gotten some practice selecting a +place to modify in Task 2. Repeat that process. Go back to the `render` page. +What is the name of the _variable_ (box containing a number) that decides what +number gets printed to screen? Go back to the big picture. Where is this +variable defined? How does it get modified when you press `enter`? + +If you're stuck, some short sections from [the Lua book](https://www.lua.org/pil/contents.html) +might help at this point: [getting started](https://www.lua.org/pil/1.html); +[assignment](https://www.lua.org/pil/4.1.html); [what you can do with numbers](https://www.lua.org/pil/3.1.html). (Buy the Lua book to support the creators of Lua. Teliva is a tiny molehill on the mountain of awesome that is Lua.) -Once you make a change, can you figure out how to restart the app with your -changes? - -After you've made a change, try exiting Teliva and restarting it with the same -app. Do you still see your changes? +Some hints: +- The function responsible for processing keystrokes is `update`. +- The variable that tracks what number to print on screen is `n`. |