add support for layouts where keys have no letters (#4)

* add support for layouts where keys have no letters

* update readme with instructions for custom layout

Co-authored-by: Guy Dupont <[email protected]>

Author: dupontgu

fw/README.md

@@ -22,4 +22,41 @@ tested natively on desktop. *For key press detection on Mac, you'll need to give
 1. Run `python3 bundle.py` from this directory. This will create a `bundle` directory, which will copy all required files into folders to be loaded onto each board.
 2. Find the directory with your board's name in the `bundle` directory. Copy all files/subdirectories onto your CircuitPython device.
 3. If your board requires third-party libraries to run this code (most do), you may have to manually copy them. Each board's `bundle` directory will contain a README listing all of the required dependencies. Official CircuitPython libraries available [here](https://circuitpython.org/libraries). As of May 2021, I have been using Bundle version 6.x.
-4. If you're using one of the desktop versions, execute `python3 code.py` from the `bundle/[macos/win32]` directory. You'll have to `pip3 install pynput` as well.
+4. If you're using one of the desktop versions, execute `python3 code.py` from the `bundle/[macos/win32]` directory. You'll have to `pip3 install pynput` as well.
+
+## Customizing the keypad layout
+
+You can customize which letters get attached to each key by changing the `keypad_dict` dictionary in `code.py`. The default is:
+```python
+keypad_dict = {
+    '1' : ['1'],
+    '2' : ['a', 'b', 'c'],
+    '3' : ['d', 'e', 'f'],
+    '4' : ['g', 'h', 'i'],
+    '5' : ['j', 'k', 'l'],
+    '6' : ['m', 'n', 'o'],
+    '7' : ['p', 'q', 'r', 's'],
+    '8' : ['t', 'u', 'v'],
+    '9' : ['w', 'x', 'y', 'z'],
+    '0' : [' ', '0', '\n'],
+    '#' : ['.', ',', '?', '!']
+}
+```
+But as [Ben Torvaney discovered](https://torvaney.github.io/projects/t9-optimised.html), you can optimize your typing even further by using something like:
+```python
+keypad_dict = {
+    '1' : ['1'],
+    '2' : ['a', 'm', 'r'],
+    '3' : ['c', 'd', 'f', 'p', 'u'],
+    '4' : ['h', 'n', 'q', 't'],
+    '5' : ['i', 'l', 'w', 'y'],
+    '6' : ['b', 'e', 'g', 'v', 'x'],
+    '7' : ['j', 'k', 'o', 's', 'z'],
+    '8' : ['8'],
+    '9' : ['9'],
+    '0' : [' ', '0', '\n'],
+    '#' : ['.', ',', '?', '!']
+}
+```
+
+**Note that the keypad will not run unless all characters are accounted for!**

fw/core/code.py

@@ -354,6 +354,10 @@ def poll_keys():
             # ignore any other keys we don't understand
             elif c < '2' or c > '9':
                 break
+            # emit for any number keys that don't have letters (if user has customized layout)
+            elif ord(keypad_dict[c][0]) < ord('a'):
+                emit_raw_text(keypad_dict[c][0])
+                break
             else:
                 # search the dictionary!
                 result = get_words(fp, c, last_result)