Template language changes

[chaley]

23 Feb 2021:

• New template function list_count_matching(v, pattern, sep)
  
  Spoiler:

  list_count_matching(list, pattern, separator) -- interprets 'list' as a list of items separated by 'separator', returning the number of items in the list that match the regular expression 'pattern'. Aliases: list_count_matching(), count_matching()
  
• New infix compare operator 'in'.
  
  Spoiler:

  Usage:
  

  pattern_expression in value_expression

  Example:
  

  program:
      if '(dragon|lizard)' in field('series') then
          'yes'
      else
          'no'
      fi

  The 'in' operator is equivalent to
  

  contains(value_expression, pattern_expression, '1', '')

  The above 'if', written with 'contains', would be
  

  program:
      if contains(field('series'), '(dragon|lizard)' , '1', '') then
          'yes'
      else
          'no'
      fi

22 Feb 2021

• Add the possibility of specifying a separator in 'for' statements, used to break the string into list items.
  
  Spoiler:

  Syntax:

  for <<id>> in <<value_expression>> separator <<expression>>:

  The keyword 'separator' and its associated expression are optional. Example:
  

  for a in some_authors separator '&':

• New function list_remove_duplicates()
  
  Spoiler:

  list_remove_duplicates(list, separator) -- return a list made by removing duplicate items in the source list. If items differ only in case, the last of them is returned. The items in source list are separated by separator, as are the items in the returned list.
  

20 Feb 2021

• Fix subitems() sometimes returning empty list items.

19 Feb 2021

• Fix 'for' not stripping leading and trailing blanks from the value assigned to the loop variable.

18 Feb 2021

• New function set_globals()
  
  Spoiler:

  set_globals(id[=expression] [, id[=expression]]*) -- Sets the value of "global variables" that can be passed into the formatter. If 'id' is not defined then set the global to the value of expression if supplied, otherwise ''. See the globals() function for more information.

17 Feb 2021:

• New function is_marked()
  
  Spoiler:

  is_marked() -- check whether the book is `marked` in calibre. If it is then return the value of the mark: either `true` (lower case) or the comma-separated list of named marks. Returns '' (the empty string) if the book is not marked. This function works only in the GUI.
  

17 Jan 2021:

• The functions add() and multiply() can now take more than 2 arguments.
• New function field_exists()
  
  Spoiler:

  field_exists(field_name) -- checks if a field (column) named field_name exists, returning '1' if so and '' if not.

3 Jan 2021:

• New function list_split()
  
  Spoiler:

  list_split(list_val, sep, id_prefix) -- splits the list_val into separate values using 'sep', then assigns the values to variables named 'id_prefix_N' where N is the position of the value in the list. The first item has position 0 (zero). The function returns the last element in the list.
  
  Example: list_split('one, two, foo', ',', 'var') is equivalent to
  var_0 = 'one'; var_1 = 'two'; var_3 = 'foo'.
  
  Example: break apart and reformat a date expressed as a format and a list of values:
  

  program:
  # date_string would normally be field() to fetch the value from the book
  # A 'date string' is a list with the first the desired format and the rest the values
  	date_string = 'YMD,1984,12, 01';
  	list_split(date_string, ',', 'li');
  	if li_0 == 'YMD' then
  		strcat(li_1, '-', li_2, '-', li_3)
  	elif li_0 == 'YM'  then
  		strcat(li_1, '-', li_2)
  	elif li_0 == 'Y'  then
  		li_1
  	else
  		'Invalid Format'
  	fi

22 Dec 2020

• New function connected_device_uuid(storage_location)
  
  Spoiler:

  connected_device_uuid(storage_location) -- if a device is connected then return the device uuid (unique id), otherwise return the empty string. Each storage location on a device has a different uuid. The location names are 'main', 'carda' and 'cardb'. This function works only in the GUI.

19 Dec 2020

• Added a 'for' template language statement. See also 22 Feb 2021 above.
  
  Spoiler:

  
  

      for <<id>> in <<expression>>:
          <<expression_list>>
      rof

  The expression must evaluate to either a metadata field lookup key, for example 'tags or '#genre', or a comma-separated list of values. If the result is a valid lookup name then the field's value is fetched, otherwise the list is broken into its individual values. Each resulting value in the list is assigned to the variable 'id'' then the 'expression_list' is evaluated.
  
  Example: This template removes the first hierarchical name for each value in Genre ('#genre'), constructing a list with the new names.
  

          program:
              new_tags = '';
              for i in '#genre':
                  j = re(i, '^.*?\.(.*)$', '\1');
                  new_tags = list_union(new_tags, j, ',')
              rof;
              new_tags

  If the original Genre is 'History.Military, Science Fiction.Alternate History, ReadMe' then the template returns 'Military, Alternate History, ReadMe'.
  
  You could use this template in calibre's 'Edit metadata in bulk -> Search & replace with 'Search for' set to 'template' to strip off the first level of the hierarchy and assign the resulting value to Genre.
  
  Note: the last line in the template, 'new_tags', isn't necessary in this case because 'for' returns the value of the last 'expression' in the 'expression list'.
  
  For completeness, note that the entire template can be replaced by the subitems() function, as in
  

  program: subitems(field('#genre'), 1, 0)

  and
  

  {#genre:subitems(1, 0)}

[chaley]

Reserved

[ownedbycats]

Perhaps this thread should be stickied?

[chaley]

Looks like "someone" did it.

I am not yet convinced that this thread should take up sticky space but we will see.

[theducks]

Originally Posted by chaley

Looks like "someone" did it. .

Peter T did it
I think <=6 should be the Max # of stickies per forum.

[capink]

I suggest removing the "Search is showing all books with some highlighted! How do I fix this?" thread from the stickies. I think/hope the issue causing this (in the Find Duplicates plugin) is fixed now. Also there is a similar thread in the main forum.

[ownedbycats]

Originally Posted by capink

I suggest removing the "Search is showing all books with some highlighted! How do I fix this?" thread from the stickies. I think/hope the issue causing this (in the Find Duplicates plugin) is fixed now. Also there is a similar thread in the main forum.

And nobody pays attention to either of them, considering the amount of threads about it...

[BetterRed]

Originally Posted by theducks

Peter T did it
I think <=6 should be the Max # of stickies per forum.

Agreed

Originally Posted by capink

I suggest removing the "Search is showing all books with some highlighted! How do I fix this?" thread from the stickies. I think/hope the issue causing this (in the Find Duplicates plugin) is fixed now. Also there is a similar thread in the main forum.

Done

BR