plover-python-dictionary-cmd

Execute arbitrary command from a Python dictionary.

Warning: While this plugin can do everything what a command plugin can, this should only be used for personal usage. If the usage is sufficiently general, it's recommended to make a Plover command plugin instead.

See also: plover-run-shell, plover-run-py, plover-open-url.

What problem does this plugin solve?

First, this assumes you know what a Python dictionary is.

Maybe you want to write a dictionary that looks like this:

LONGEST_KEY = 1

def lookup(key):
    if key == ("SKWR-F",):
        return "{PLOVER:OPEN_URL:https://www.openstenoproject.org/}"

The {PLOVER:OPEN_URL:…} obviously opens the said URL, using Plover Open URL plugin.

Problem: what if the task you want to do is not already covered by some command plugin?

While you can certainly write a new command plugin, that is rather time-consuming.

The following will not work:

import webbrowser

LONGEST_KEY = 1

def lookup(key):
    if key == ("SKWR-F",):
        webbrowser.open("https://www.openstenoproject.org/")

It's because the dictionary may be looked up multiple times.

The solution

Write the plugin like the following.

import webbrowser
import plover_python_dictionary_cmd

LONGEST_KEY = 1

@plover_python_dictionary_cmd.register
def f(engine):
    webbrowser.open("https://www.openstenoproject.org/")

def lookup(key):
    if key == ("SKWR-F",):
        return str(f)  # or: f.str_with_args()

As an extra bonus, you get access to the engine object inside the function f above.

Extra

f.str_with_args() works as follows: f.str_with_args(1, 2) returns a string, which when interpreted as a Plover command and executed, will call f(engine, 1, 2).

As such, you can also modify the code above as follows:

@plover_python_dictionary_cmd.register
def f(engine, url):
    webbrowser.open(url)

def lookup(key):
    if key == ("SKWR-F",):
        return f.str_with_args("https://www.openstenoproject.org/")

Internal implementation detail

It uses a global lookup table to store the reference to the function f. Then str(f) as above returns something like {plover:python_dictionary_cmd:123456} where 123456 is some unique ID.

Don't rely on this implementation detail.