How do I type these characters?!?!?!?
Step 1: go to Amazon and buy a special APL typewriter keyboard...
Just kidding (thankfully). In the modern day and age, there are way better options:
Simplest: Press the buttons in the IDE
At the top of the TryAPL page (and this course page) there are symbols you can click. You can also hover over them to get a quick overview of what each symbol does in APL.
This is, however, quite slow when you need to write APL code fast. Find some alternatives below.
Quickest: Use keyboard shortcuts
On TryAPL (and this page), you can use prefixes to insert various special symbols.
You can use any of the following keys as a prefix: ` § ° ² µ º ½ ù
On Finnish keyboards, the § key (located to the left of 1) is the easiest to use. On US and UK keyboards, the ` key is preferred. Whichever key you pick we will denote as PREFIX from now on.
To use prefixes, hit whatever prefix key you are using, followed by the key you want to type.
For example, the multiplication symbol × is inserted by typing PREFIX -
and division ÷ is inserted with PREFIX =.
While these might seem unintuitive at first, you'll get used to them fairly quickly.
You can see the completion shortcut if you hover over the symbol in the top language bar.
For example, hovering over × shows tells you the following: Prefix: <prefix> -.
These are just instructions telling you to do what we did above.
Quickest (alternative): Tab completion
Sometimes, if you have a Finnish keyboard, you will be unable to type certain prefix shortcuts that were designed for US keyboards. Thankfully, there is an alternative: tab completions. You can find the keys needed for tab completion in the same tooltip that shows you what keys to use for the prefix shortcuts.
For example, hovering over the arrow symbol (←) shows the follwing information: < - <tab>.
Just follow the instructions and hit the keys < - Tab.
You'll notice that the alternative, PREFIX [ is impossible to type on a Finnish keyboard,
as it doesn't have a separate [ key (and using AltGr breaks the APL shortcut).
Note!
Tab completion is only required for non-US users due to a bug feature in TryAPL,
which is that it's designed with only US keyboards in mind.
When we install the Dyalog IDE in a future chapter, this will no longer be a concern, as that supports Finnish (and various other non-US) keyboards natively.
Excessive: Install the APL Keyboard
You can install a dedicated keyboard for APL glyphs. See further instructions on the Dyalog website. This method provides no extra benefits unless you want to type APL outside of TryAPL, this webpage, or the IDE.
We will also see in a later chapter how to install a plugin for Visual Studio Code that allows you to type APL characters.