Template language changes

[chaley]

Originally Posted by ownedbycats

so for a custom column, it's just #whatever?

Yes, but in quotes. It is an expression returning a lookup name. You could even use

('t' &'ags')

if for some reason you wanted to do that.

[chaley]

Originally Posted by ownedbycats

EDIT: I pulled the latest changes but I am not seeing inlist_field.

It is an operator, not a function. There isn't anywhere for you to "see" it other than by using it.

Another example:

program:
	if '^science' inlist_field '#genre' then 'yes' else 'no' fi

NB: I forgot to add the new operator to the syntax highlighting in the template tester so it doesn't yet show as blue. I submitted the required change.

[ownedbycats]

Ah, I was looking in the function reference. It works when I tried it.

[ownedbycats]

Does inlist_field only work for strings? e.g.:

program:

	readgoal = strcat('readinggoal:', format_date(today(), 'yyyy'));

	if
		readgoal inlist_field '#admintags'

[chaley]

Originally Posted by ownedbycats

Does inlist_field only work for strings? e.g.:

program:

	readgoal = strcat('readinggoal:', format_date(today(), 'yyyy'));

	if
		readgoal inlist_field '#admintags'

Yes, because there isn't a calibre multiple-value field that doesn't contain strings. Note that in your example, the string generated by strcat() must exactly match some item in #admintags', including blanks. That said, if it works with inlist then it will work with inlist_field.

EDIT 2: the changes to the syntax highlighter are now in calibre source.

[chaley]

28 Oct 2024 (in calibre source)

• Improvement to template function has_notes. It now has two variants.
  1. has_note(field_name, field_value) -- if field_value is not '' (the empty string) , return '1' if the value field_value in the field field_name has an attached note, otherwise ''. Example:
     

     has_note('tags', 'Fiction')

     returns '1' if the tag "fiction" has a note, otherwise ''.
     
  2. (NEW) has_note(field_name, '') -- if the second parameter is '' then return a list of values in field_name that have a note. If no item in the field has a note, return ''. Example:
     

     has_note('authors', '')

     returns a list of authors that have notes, or '' if no author has a note.
  For example, the second variant is useful for showing column icons if any value in the field has a note rather than a specific value.
  
  You can also test if all the values have a note by comparing the list length of this function's return value against the list length of the values in field_name. Example:
  

  list_count(has_note('authors', ''), '&') ==# list_count_field('authors')

[thiago.eec]

Nice. Even simpler. Now I can find all authors without a note like this:

not template:"""program:
	if $authors in has_note('authors', '') then
		'1'
	else
		 ''
	fi;#@#:t:1"""

[chaley]

Originally Posted by thiago.eec

Nice. Even simpler. Now I can find all authors without a note like this:

not template:"""program:
	if $authors in has_note('authors', '') then
		'1'
	else
		 ''
	fi;#@#:t:1"""

That search finds books where all authors don't have notes, not any author that doesn't have a note. It compares two lists as strings, not as lists, so the "in" is true if the has_note() result string equals the authors string, which means all authors have notes.

It will also be at least 10 times slower than the template I posted in the other thread. Perhaps as much as 50 times slower. Of course, this only matters if you have lots of books.

This template uses the new has_note() to find books where 1 or more authors don't have a note. It works by returning '1' if all authors for a book have notes, otherwise ''. It will be slightly faster than your template, but nowhere near as fast as the python template.

program:
	if list_count(has_note('authors', ''), '&') ==# list_count_field('authors') then
		return '1'
	fi;
	''

You could eliminate the outer "not" in the search by making changing the return '1' to return '' and changing the last line to '1'.

[thiago.eec]

Oh, I see my mistake now. I'll leave the python template, then.

When using my template, I do think the first time was slow, then other times were fast. I guess it's the work of the cache in action.
________________________

EDIT: I decided to check the difference between the two templates (mine and yours, but not the python one). It seems to find the same results, even if only one author has a note. Then, looking again at the code, I notice it does work:

Example: If i have a book with two authors (AuthorA and AuthorB), and only have notes for AuthorA.

$authors = 'AuthorA & AuthorB'
has_note('authors', '') = 'AuthorA'

Now, the comparison if $authors in has_note('authors', '') will return False, as intended.

But I'm definitely staying with the python template.