[GUI Plugin] Action Chains

[capink]

Originally Posted by chaley

@capink: specifying a separator in a for statement and the function list_remove_duplicates(l, sep) are now available in master source.

Thanks for both. I don't seem to know how to use the new for loop. I am trying to modify your previous template to this:

program:
	all_authors = category_items('authors');
	res = '';
	for a in '&' all_authors:
		ratings = from_search('rating', strcat('rating:true and author"=', a, '"'));
		if ratings then
			avg = divide(mean(ratings), 2);
			res = list_union(res, strcat(a, ':', avg), ',')
		fi
	rof;
	res

Obviously I am doing something wrong (and probably silly) here.

[chaley]

Originally Posted by capink

Thanks for both. I don't seem to know how to use the new for loop. I am trying to modify your previous template to this:

The syntax is

	for a in authors separator '&':

I used the keyword 'separator' to remove some ambiguity in the language parser. Note that the 'thing' following the keyword is an arbitrary expression. You can do something like this, admittedly a bit strange:

	for a in authors separator if something then '&' else ',' fi:

[capink]

Originally Posted by chaley

[/CODE]I used the keyword 'separator' to remove some ambiguity in the language parser.

That makes senese. It is now working for me.

program:
	book_ids = from_selection('id');
	all_authors = category_items('authors',book_ids);
	res = '';
	for a in all_authors separator '&':
		ratings = from_search('rating', strcat('rating:true and author:"=', a, '"'));
		if ratings then
			avg = divide(mean(ratings), 2);
			res = list_union(res, strcat(a, ':', avg), ',')
		fi
	rof;
	res

Using all authors without restricting them using from_search() or from_selection() on large libraries is not recommended as it is verrrrrrry slow.

Originally Posted by chaley

Note that the 'thing' following the keyword is an arbitrary expression.

Wow. I will sure come up with a use for that sometime in the future.

[capink]

Also turns out subitems() automatically removes duplicates anyway. So this works fine to get the top level genres:

program:
    genres = category_items('#genre');
    subitems(genres, 0, 1)

[ownedbycats]

Question: In View Manager, I have a view called "On Device." I use a one-action chain and Event Manager to switch to it when the device plug in.

Is it possible to make a condition to make it not run if the view is already set to On Device?

Thank you!

[capink]

You will need a custom template function to check for that. Taking a quick look at the view manager code, this can be easily done using this template:

from calibre_plugins.action_chains.templates import TemplateFunction

class ViewManagerLastVIew(TemplateFunction):

    name = 'view_manager_last_view'
    arg_count = 0

    def evaluate(self, formatter, kwargs, mi, locals):
        import calibre_plugins.view_manager.config as cfg
        gui = self.plugin_action.gui
        library_config = cfg.get_library_config(gui.current_db)
        return library_config.get(cfg.KEY_LAST_VIEW, '')

Copy/Paste the above code into the module manager. Now you can use this function in a condition as follows:

Template        : program: view_manager_last_view()
Datatype        : text
Comparison      : !=
Condition Value : On Device

However, your request uncovers another problem. When the conditions are not met, an error dialog will pop-up. This might not be suitable for events. I can turn this off for events and let it fail silently, or add an option in the conditions dialog to make the error dialog optional. Will think about it to see which of these two options is more suitable, and then add it later.

In the mean time, you can test the above to see whether it works.

[ownedbycats]

A while ago I did some experimenting and found that adding the condition to the actions rather than the chain itself doesn't result in error. This is clumsy though, and doesn't work if you want to use other conditions for the specific actions.

But it works well enough for a single-action chain, and the code above worked.