# Syster Syster is a way to input symbols in a different way: instead of macros, Leader sequences or the like, we trigger the special input mode, and enter the symbol's name. Once finished, we hit `Space`, and this plugin will do the rest: delete everything we typed, look up an action for the entered symbol, and execute that. There are a number of ways this can be useful, but the easiest showcase is symbolic Unicode input: `SYSTER coffee SPACE` turns into `☕`, with just a little code. ## Using the plugin To use the plugin, one needs to include the header and set up a function that will handle the symbol actions: ```c++ #include <Kaleidoscope.h> #include <Kaleidoscope-EEPROM-Settings.h> #include <Kaleidoscope-HostOS.h> #include <Kaleidoscope-Syster.h> #include <Kaleidoscope-Unicode.h> void systerAction(kaleidoscope::plugin::Syster::action_t action, const char *symbol) { switch (action) { case kaleidoscope::plugin::Syster::StartAction: Unicode.type (0x2328); break; case kaleidoscope::plugin::Syster::EndAction: handleKeyswitchEvent (Key_Backspace, UnknownKeyswitchLocation, IS_PRESSED | INJECTED); Kaleidoscope.hid().keyboard().sendReport(); handleKeyswitchEvent (Key_Backspace, UnknownKeyswitchLocation, WAS_PRESSED | INJECTED); Kaleidoscope.hid().keyboard().sendReport(); break; case kaleidoscope::plugin::Syster::SymbolAction: Kaleidoscope.serialPort().print ("systerAction: symbol="); Kaleidoscope.serialPort().println (symbol); if (strcmp (symbol, "coffee") == 0) { Unicode.type (0x2615); } break; } } KALEIDOSCOPE_INIT_PLUGINS(EEPROMSettings, HostOS, Unicode, Syster); void setup() { Kaleidoscope.serialPort().begin(9600); Kaleidoscope.setup (); } ``` **Note** that we need to use the `Syster` object before any other that adds or changes key behaviour! Failing to do so may result in unpredictable behaviour. ## Plugin methods The plugin provides the `Syster` object, with no public methods. There are two methods outside of the object, however, that can be overridden: ### `systerAction(action, symbol)` > Called whenever an action needs to be taken, which can happen in three cases: > First, when the `Syster` key is pressed and the alternate processing starts. > In this case, `action` will be set to > `kaleidoscope::plugin::Syster::StartAction`, and `symbol` will be `NULL`. This > function can be used to do some setup to make it more obvious that the Syster > input mode is active, such as sending a Unicode symbol to the host, or > lighting up LEDs, or anything else we'd like. > > Second, when the sequence is finished with a `Space`. In this case, `action` > will be set to `kaleidoscope::plugin::Syster::EndAction` and `symbol` will be > `NULL`. This can be used to undo anything that the start action did, if need > be. > > Third, when the action for the symbol should be made. In this case, `action` > is set to `kaleidoscope::plugin::Syster::SymbolAction`, and `symbol` will be a > C string. It is up to us, what we do with this information, how we handle it. ### `keyToChar(key)` > A function that turns a keycode into a character. If using QWERTY on the host, > the default implementation is sufficient. When using something else, you may > have to reimplement this function. ## Dependencies * [Kaleidoscope-Ranges](Kaleidoscope-Ranges.md) ## Further reading Starting from the [example][plugin:example] is the recommended way of getting started with the plugin. [plugin:example]: /examples/Keystrokes/Syster/Syster.ino