Entering APL Symbols
APL uses a variety of symbols to represent its built-in functions. Many of these are symbols that do not exist on a standard keyboard. Some of these will be familiar (for example,
The QuickSymTM pop-up
If you are completely new to APL, you will probably find it easiest, at least to start with, to use the QuickSymTM feature of APLX. By pressing a single key (usually the 'Menu' key in Windows, or a function key - by default F1 - under MacOS), you can bring up a panel which displays the APL symbols. This is described in the next section.
Using an extended keyboard layout
The traditional way of entering special APL symbols is to use one of the extended keyboard layouts which APLX provides. You will probably want to use the 'unified' layout which is selected by default. This is configured as follows (the exact layout will vary according to the country in which you live and the specific model of keyboard):
As you can see, each key is shown with up to four symbols. As with a conventional keyboard, a given character key generates a lower case character and, when depressed in conjunction with the Shift key, the corresponding upper case character. These are shown in black and red on the above diagram, in the lower-left and upper-left positions on each key.
In order to enter the other symbols, you use the AltGr key, which acts just like the Shift key in that it modifies the effect of another key. (In non-APL applications, AltGr is used to type various different characters, primarily ones that are unusual for the locale of the keyboard layout, such as foreign currency symbols and accented letters.) Using the AltGr key with another key produces the symbol displayed in green, on the lower right of each key in the diagram above. The remaining symbols (shown in blue, on the top right of each key) are entered by pressing the AltGr and Shift keys simultaneously. (Note: On a Macintosh keyboard, use the Alt or Option key instead of AltGr).
For example, the key in the upper row of the keyboard, inscribed with the digit 4, produces the following symbols:
If you have problems with the keyboard (e.g. because your keyboard does not have an AltGr key), see here.
Choosing and customizing the keyboard layout
APLX supports three keyboard layouts. These are:
1) The Unified APL layout, as shown above. This is similar to an ordinary ASCII keyboard layout for unshifted and shifted keys. Special APL symbols are obtained by using AltGr or Shift-AltGr combinations. If you are learning APL we recommend that you use this layout.
2) The Standard or Traditional APL layout. This is based on the traditional APL keyboard where alphabetic keys unshifted give upper-case letters, shifted give APL symbols, and with the Alt or AltGr key give lower-case letters. It is recommended only for people who are used to programming in APL using a special APL keyboard.
3) The Default non-APL layout. In this mode, keyboard mapping is the same as in non-APL applications. For example, in the US it would usually be the ordinary US QWERTY keyboard. In France it will usually be the French AZERTY keyboard.
You can select which layout you want to use by selecting the Keyboard Layout item in the Tools menu of APLX's Session window. In addition, you can at any time swap between the Default non-APL layout and your preferred APL layout (Standard or Unified) by pressing Ctrl-N (or Cmd-N on the Macintosh). This is very useful for entering comments and text in APL functions, especially if you are using a language other than English
The current keyboard layout can be shown at any time by selecting the Keyboard Layout item in the Help menu. Under Windows, you can also display this by pressing Ctrl-F1.
Customizing the keyboard layout
You can customize the keyboard layout using the Keyboard tab of the Preferences dialog. This allows you to move specific characters around on the keyboard, or set up a completely different keyboard mapping if you prefer.
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