Loop over list

[ivanm]

Calibre already has the list_re function to be able to apply a regex to every element of a list, but is there any way of applying other functions to list elements?

(Specifically I want to be able to apply shorten to every element of a list; I want to be able to achieve something like the sample program listing in the Calibre template language reference but my series column is often a `.' separated list of nested series.)

[chaley]

No, there isn't a way to do that in the template language. For various technical reasons it isn't possible (requires deferred evaluation).

You can of course do this in a custom template function (Preferences / Template Functions) where you have full python available. You can call standard template functions in a custom function, but it is enough of a pain that you might be better off doing your own shorten.

[ivanm]

That's what I was afraid of.

Are custom template functions stored in the library or in the preferences? (That is, if I just copy my ~/Calibre Library/ directory to another computer, will that include the custom function?)

[chaley]

Originally Posted by ivanm

Are custom template functions stored in the library or in the preferences? (That is, if I just copy my ~/Calibre Library/ directory to another computer, will that include the custom function?)

They are in the library, specifically in the metadata.db.

Another way to do this is to write a "calibre" command line python script that does the work on all the books. That way you could run it on any library you want. There is an example of such a script in this thread.

[ivanm]

So I've tried writing my own function that applies that entire shortening/initialisation process over each element of a series list, but I when I try and use it I get the error "EXCEPTION: global name re is not defined"; adding "import re" at the top of the definition didn't work.

Alternatively, how do I call standard template functions in a custom function? The documentation just says that all instructions are in the dialog, and it just says the required syntax, not how to call other functions. (I haven't done much Python for a while; I usually use Haskell, so I'm not used to trying to find dynamically-typed values in an object )

[chaley]

Here is a template function that uses re. Don't worry about what it does.

def evaluate(self, formatter, kwargs, mi, locals, val, is_read_pct,  
				is_reading_str, no_page_read_str):
	try:
		test_val = int(is_read_pct)
	except:
		return 'is_read_pct is not a number'

	import re
	pattern = u'.*(\d+[-/]\d+[-/]\d+).*?Dernière page lue : Emplacement \d+ \((\d+)%\)'
	mg = re.match(pattern, val, re.U + re.I + re.DOTALL);
	if mg is None:
		return no_page_read_str
	date = mg.group(1)
	pct = mg.group(2)
	try:
		f = int(pct)
		if f > test_val:
			return date
		elif f > 0:
			return is_reading_str + ': ' + pct + '%'
	except:
		pass
	return no_page_read_str

[ivanm]

Wait, you can do an import mid-code in Python?

shakes head at the silly language

Anyway, ta muchly chaley!