[GUI Plugin] Template Catalog

[DrChiper]

Originally Posted by Terisa de morgan

YFor me, I'm using only title or author because they add an icon to the column.

No offense, but is there some reason why you do not use column coloring? It seems to me somehow easier.

Originally Posted by Terisa de morgan

You can add author For me, I'm using only title or author because they add an icon to the column. About nil variable... no idea.

I think only the true calibre gurus will be able to answer this (not for us mortals)
What I meant is this: when our template code is parsed and it evolves into a not-situation (no non-ASCII code, or no title present), then the remainder of the template code on the same code line is not further processed, and immediately the next line is processed. So when the IF statement is FALSE, any ELSE statement (when present) is executed.
I noticed this behavior when I made a mistake in the IF part and it was not noticed until I had a title which did happened to have a non-ASCII character and only then triggered the formatter on the error.

[Terisa de morgan]

Originally Posted by DrChiper

No offense, but is there some reason why you do not use column coloring? It seems to me somehow easier.

No offense taken. I have A LOT of column coloring, for different conditions, so the icons are more visible.

Originally Posted by DrChiper

I think only the true calibre gurus will be able to answer this (not for us mortals)

I agree

Originally Posted by DrChiper

What I meant is this: when our template code is parsed and it evolves into a not-situation (no non-ASCII code, or no title present), then the remainder of the template code on the same code line is not further processed, and immediately the next line is processed. So when the IF statement is FALSE, any ELSE statement (when present) is executed.

I noticed this behavior when I made a mistake in the IF part and it was not noticed until I had a title which did happened to have a non-ASCII character and only then triggered the formatter on the error.

So, the template language has a short-circuit evaluation. Glad to know (I declare myself guilty of assuming this behavior, and have coded based on that).

[chaley]

Originally Posted by DrChiper

The reason I didn't use intermediate vars is because I noticed that the formatter stops processing/evaluating in case of a nil situation, so this seems to be fastest way to process. But as always, correct me if I'm wrong

This is called "shortcutting". If the formatter can determine that a "then" or "else" clause cannot be evaluated then it skips it. The same thing happens with "and" and "or" expressions. For example, given the expression

'1' || print('foo')

will never print 'foo' because the result of the || is true no matter what the right-hand side does. On the other hand

'1' && print('foo')

will always print 'foo' because both the left-hand and the right-hand must be true for the expression to be true.

program:
	if (field('title')!=transliterate(field('title')))
	then
		if (field('#subtitle')!=transliterate(field('#subtitle')))
		then
			'true1, true2'
		else
			'true1'
		fi
	else
		if (field('#subtitle')!=transliterate(field('#subtitle')))
		then
			'true2'
		else
			'false'
		fi
	fi

It returns true1 for title, true2 for subtitle, or false when neither contains non-ASCII chars.

FWIW and perhaps doing premature optimization: this will be a bit faster because a) local variables are faster than field lookups, and b) switch_if is faster than a series of ifs.

program:
# These two lines depend on evaluation being left to right so the
# variable is set before use.
	title_neq = (t = $title) != transliterate(t);
	authors_neq = (a = $authors) != transliterate(a);

# This code works because given two booleans the "truth table" has four entries.
# The order of evaluation is important. As it is we can avoid extra tests because
# if the first test isn't true then one or both of title_neq and authors_neq 
# must be false. That is why the second and third line don't need to check the
# other variable. The switch_if function does shortcutting.

	switch_if(
		title_neq && authors_neq, 'true1, true2',
		title_neq, 'true1',
		authors_neq, 'true2',
		'false')

The switch_if's arguments can be reordered if one pathway, probably resulting in 'false', is the most common. For example:

program:
	title_neq = (t = $title) != transliterate(t);
	authors_neq = (a = $authors) != transliterate(a);

	switch_if(
# True if both are false
		!(title_neq || authors_neq), 'false',
# True if both are true
		title_neq && authors_neq, 'true1, true2',
# Here, one but not both of title_neq and authors_neq is true.
		title_neq, 'true1',
# title_neq was false so authors_neq must be true.
		'true2')

[DrChiper]

Originally Posted by Terisa de morgan

No offense taken. I have A LOT of column coloring, for different conditions, so the icons are more visible.

Must be a colorful experience. Now to remember what all those colors mean ...
(I only use 3 and have still problems to remember them...)

[DrChiper]

Originally Posted by chaley

This is called "shortcutting".

Right. I knew its behavior, but can't remember whether I have heard this name before.

Originally Posted by chaley

FWIW and perhaps doing premature optimization: this will be a bit faster because

1. a) local variables are faster than field lookups, and
2. b) switch_if is faster than a series of ifs.

Good to know. I used to use local variables but was not sure whether they were to be preferred within calibre or not.

Originally Posted by chaley

	switch_if(
		title_neq && authors_neq, 'true1, true2',
		title_neq, 'true1',
		authors_neq, 'true2',
		'false')

The good old "WITH" statement Yes, I was looking to something similar, but was to lazy to RTFM (I do just occasionally some small coding effort within calibre, when the need arises that is)

Well the Template Catalog Plugin seems interesting (I had indeed asked myself how to control all those templates defined at various places) but this might help a lot.

Perhaps now a description about the do's and don't's of template creation, anybody?

[Terisa de morgan]

Originally Posted by DrChiper

Must be a colorful experience. Now to remember what all those colors mean ...
(I only use 3 and have still problems to remember them...)

Yeeees, you have nailed it....

[Comfy.n]

Originally Posted by BetterRed

If I export the icon rules from Look and Feel I can see the column to which the icon is attached e.g.



I cannot see that column name in Template Category list or in the Edit/Save dialogue.

Could the name if the column to which the icon is attached be incorporated into the Template Name e.g.… rather than "From column_icon_rules: Rule 1" something like this "authors: Rule 1".

And something similar for column colour templates.

BR

Thanks for your recommendation, BR. I have uploaded version 1.3 which hopefully meets your suggestion.

I have also adjusted some custom icons that were not properly referenced, hope you folks like it.

[BetterRed]

Originally Posted by Comfy.n

Thanks for your recommendation, BR.
I have uploaded version 1.3 which hopefully meets your suggestion.

I have also adjusted some custom icons that were not properly referenced, hope you folks like it.

You also clobbered many of my custom keyboard shortcuts - see attachment.

Plugin removed, they seem to be back.

Added: Manage Categories is a core calibre feature, IMO we don't need another one



BR

[Comfy.n]

Originally Posted by BetterRed

You also clobbered many of my custom keyboard shortcuts - see attachment.

Plugin removed, they seem to be back.

Added: Manage Categories is a core calibre feature, IMO we don't need another one

Attachment 214421

BR

Fixed, sorry for that. Now I have set the plugin to register just one empty shortcut for main dialog that users may customize. Tab and space can be used to navigate through buttons as usual.

[Terisa de morgan]

Is still necessary to uninstall the previous version or we can just add it now?

[Comfy.n]

Originally Posted by Terisa de morgan

Is still necessary to uninstall the previous version or we can just add it now?

On a quick test I made by installing the previous version, then installing the latest one, I saw the shortcut I had set manually for this new version take effect. So I think you may safely install over previous version without uninstalling it.

[Comfy.n]

Version 1.5 - fixes an issue where description info wouldn't refresh

[Comfy.n]

Uploaded version 2.0!

• Catalog can be exported as .MD (Markdown format), which makes it easier to convert catalog to other formats using Calibre. I recommend .docx!
  
• Five backup copies are kept. Details on first post, "Latest updates" section!