Templates: various questions not worth their own thread

[chaley]

Originally Posted by ownedbycats

When using a template in Action Chains to set a boolean column, should I use "Yes/No" or "True/False"?

Either one.

True/False have a small advantage; they work in all languages. Yes/No are translated.

NB: use '' to set it to undefined.

[ownedbycats]

That makes sense, though it's also a bit confusing because searching #bool:true and #bool:false will check that they're defined/undefined.

[chaley]

Originally Posted by ownedbycats

That makes sense, though it's also a bit confusing because searching #bool:true and #bool:false will check that they're defined/undefined.

Because in search that is what true and false mean for all column types. True checks for "has any value". False checks for "has no value". The boolean False is a value under those rules.

Also and FWIW: in your template you can also return '1' for True and '0' for False.

[capink]

Both will work (yes/no & true/false) with Action Chains. But better to stick with the Yes/No to be in line with what Calibre uses for the column. Also 0/1 will work.

[ownedbycats]

Originally Posted by chaley

Because in search that is what true and false mean for all column types. True checks for "has any value". False checks for "has no value". The boolean False is a value under those rules.

Also and FWIW: in your template you can also return '1' for True and '0' for False.

I also noticed that when I used bistate booleans, true/false also worked the same as yes/no. I had to fix a bunch of saved searches when I switched to tristate.

now I am curious, how does searching for #bool:yes/no work with translations?

[chaley]

Originally Posted by ownedbycats

I also noticed that when I used bistate booleans, true/false also worked the same as yes/no. I had to fix a bunch of saved searches when I switched to tristate.

That is because bistate bools are implemented using tristate. Undefined is used for the False value.

now I am curious, how does searching for #bool:yes/no work with translations?

The rules from the code:

First the local (translated) words are determined. This is for English.

• self.local_no = icu_lower(_('no'))
• self.local_yes = icu_lower(_('yes'))
• self.local_unchecked = icu_lower(_('unchecked'))
• self.local_checked = icu_lower(_('checked'))
• self.local_empty = icu_lower(_('empty'))
• self.local_blank = icu_lower(_('blank'))

The comparisons are below. The quoted strings are literal, not translated.

• Value 'True': self.local_yes, self.local_checked, 'checked', '_checked', 'yes', '_yes', 'true'
• Value 'False':self.local_no, self.local_unchecked, 'unchecked', '_unchecked', 'no', '_no', 'true'
• Value Undefined: self.local_empty, self.local_blank, 'blank', '_blank', 'empty', '_empty', 'false'

To head off the inevitable next question, '_yes' etc exist because it is possible the the translation of (for example) 'Empty' is 'Yes'. The words 'true' and 'false' are reserved.

[ownedbycats]

When doing a check_yes_no, I noticed that 1, '', '' and 1, 0, 0 both worked. Is there a difference between 0 and null?

[chaley]

Originally Posted by ownedbycats

When doing a check_yes_no, I noticed that 1, '', '' and 1, 0, 0 both worked. Is there a difference between 0 and null?

The function checks '1' for 'True'. Anything else is False. Thus

check_yes_no(#a, 'Klingons', 'rule', 1)

is equivalent to

check_yes_no(#a, 0, 0, 1)

[ownedbycats]

Should local variables work for check_yes_no?

e.g.

program:
k = $$#kobocoll;
o = field('#onkobo');
if check_yes_no(o, 0, 1, 0) then 'sync.png' 
elif check_yes_no(o, 0, 0, 1) then
	if list_contains(k, ',', '^Kobo Store$', '1', '') then 'drm-locked.png'
	elif list_contains(k, ',', '^Send to Device$', '1', '') then 'sync.png'			
	else 'reader.png'
	fi
fi

results in null values where putting in the check_yes_no('#onkobo', x, x, x) gives results

[chaley]

Originally Posted by ownedbycats

Should local variables work for check_yes_no?

No, not in the way you think. Because check_yes_no() needs the raw value it requires the name of the field, not the value of the field. Thus this will work

program:
	f = '#mybool';
	check_yes_no(f, 1, 1, 1)

but this will not. The value is always considered to be undefined.

program:
	f = $#mybool;
	check_yes_no(f, 1, 1, 1)

If you want to use a local variable containing a value then you must do something like this:

program:
# must use raw_field()
	f = $$#mybool;
# A bool column fetched with raw_field will have 1 of 3 values, True, False, or None
	if f == 'true' then
		'yes'
	elif f == 'false' then
		'no'
	elif f == 'none' then
		'undefined'
	else
		'what?'
	fi

Another way of saying the above is

program:
# must use raw_field()
	f = $$#mybool;
	first_non_empty(
		test(f == 'true', 'yes', ''),
		test(f == 'false', 'no', ''),
		test(f == 'none', 'undefined', '')
	)

[ownedbycats]

I put o = '#onkobo'; and that worked. I will remember that.

Question: Could a stored template be used to share the same code between a column icon and emblem?

I saved some templates I have in both places (reading_status, kobo_status, and format_icons) but I am not quite sure how to get them to work. The dialog says to use the 'call' function but I think I did it wrong as I just got an error about it being unknown.

[chaley]

Originally Posted by ownedbycats

Question: Could a stored template be used to share the same code between a column icon and emblem?

Yes.

I saved some templates I have in both places (reading_status, kobo_status, and format_icons) but I am not quite sure how to get them to work. The dialog says to use the 'call' function but I think I did it wrong as I just got an error about it being unknown.

The documentation is wrong. I will fix it.

You use a stored template just as you use a template function, stored_template_name(args).

If you update source you will see some improvements in the stored template dialog. The most important is there is now a "test" button that opens a subsidiary template tester so you can try the stored template(s) without leaving the preferences dialog.

Example of definition and use of a stored template:

Definition:

The program text:

program:
	arguments(lst='No list argument given', items='');
	r = '';
	for l in items:
		if !r then
			r = str_in_list(lst, ',', l, l, '')
		fi
	rof;
	if !r then
		r = sublist(list_sort(lst, 0, ','), 0, 1, ',')
	fi;
	r;

How to call it

program: list_priority_item($tags, 'foo')

[ownedbycats]

Thank you

How do I add a comment to a template? Sometimes I forget what specific parts of a GPM template are meant to do.

[chaley]

Originally Posted by ownedbycats

How do I add a comment to a template? Sometimes I forget what specific parts of a GPM template are meant to do.

Comments are lines starting with a ‘#’ character. Comments beginning later in a line are not supported.

[ownedbycats]

Thank you.

How do I escape a forward slash? the first if of this statement isn't working for me. I tried adding a second slash to escape it but it errored too.

program:

if $$#fanficcat then
    list_re($tags, ',', '\.', '!')

elif $formats == 'PDF' then
   'PDF'

else
    list_re($tags, ',', '^(.*?)($|\..*$)', '\1')
fi

Also, how would you apply a sublist of just first item to the list_re? See the third item in the screenshot. I tried enclosing it but I broke it. This is for my #kobopath composite for a save template.