Everything depends on a good, valid config file. For this tutorial, we’ll use the
following short YAML (found in the Github repo as
case_sensitive: False screen_width: 80 tabs: - tab_header_input: a tab_header_description: Menu a items: - item_choice_displayed: 1 item_description: First choice item_inputs: - 1 item_returns: choice1 - item_choice_displayed: 2 item_description: Second choice item_inputs: - 2 item_returns: choice2 - tab_header_input: b tab_header_long_description: You have just selected Menu B items: - item_choice_displayed: x,y,x item_description: x or y or z item_inputs: - x - y - z item_returns: xyz - item_choice_displayed: q item_description: Quit item_inputs: - Q - qUiT - bye item_returns: quit
This is a config for two tabs, each with two choices.
First, import the
>>> from pytabby import Menu
Then, you need a config file. There are two static methods you can call from the
read_json path. Or you can
write a python dict and pass that. Here, let’s read the YAML file.
>>> config = Menu.safe_read_yaml('tutorial.yaml') # the file shown above
And now instantiate the class with the config dict:
>>> menu = Menu(config)
At this point, if your config has an invalid schema, the Menu class will raise an InvalidSchemaError and will output ALL the schema violations to stderr. (As opposed to raising just one, Then you fixing it, then raising another, you fixing it, etc.)
If the menu instance is instantiated without errors, you can just run it!
You’ll see the following printed to stdout:
[a:Menu a|b] ======== --  First choice  Second choice ?: ▓
Note that the first tab, a, is underlined, showing that it’s the active tab. Tab b has no description in the config, so it’s very short.
Now enter ‘c’ (an invalid choice) at the prompt. A new line appears (the program does not resend the entire meny to stdout):
?: c Invalid, try again: ▓
Now enter ‘b’ to switch to that tab. The following is sent to stdout:
Invalid, try again: b Change tab to b You have just selected Menu B [a:Menu a|b] -------- == [x,y,x] x or y or z [q ] Quit ?: ▓
As you can see, the second tab,
b, is now underlined. (It really is more obvious if you use descriptions.)
The program output
Change tab to & the tab_header_input
Since for this second tab, ‘tab_long_description’ was defined, that was printed as well (
You have just selected Menu B, how boring).
Now let’s actually submit a valid choice (an invalid choice will give the same ‘Invalid, try again: ‘ message as above).
?: x ('b', 'xyz')
Now the menu has returned a value, a tuple of the tab input and the return value. The tuple is returned because different tabs could
have the same return value. If there were only one tab, only the return value
'xyz' would have been returned.