How to write templates?

[Fynjisx]

Hello. I am a beginner and don't know many functions of caliber. I started studying templates and misunderstood a lot. Can you tell and apply examples of what templates help to do that cannot be achieved with ordinary means?

[ownedbycats]

First off, check out the template documentation. Bookmark it too.

I'll try to explain a few things with one of my own templates.

Here's part of a somewhat simple GPM template made to display icons for various fanfics rather than a zillion different column icon rules:

program:
	f = $#fanficcat;

   strcat(
		if "^Fallout$" inlist f then 'fallout.png:' fi,
		if "^Half-Life$" inlist f then 'halflife.png:' fi,
		if "^(Mass Effect Trilogy|Mass Effect: Andromeda)$" inlist f then 'masseffect.png:' fi,
		if "^The Elder Scrolls$" inlist f then 'theelderscrolls.png:' fi,
		if "^Pokémon$" inlist f then 'pokemon.png:' fi,		
		if "^Portal$" inlist f then 'portal.png:' fi,
   )

Defining things:

f = $#fanficcat;

Here, I am telling the template that 'f' means the value of the #fanficcat column. A column 'field reference' can be preceded with $ or $$; the former is input, while the latter is 'raw' input (the latter mostly matters for datetimes, which have a lot of different formattings).

While in the fanfic icon example I'm just using it as shorthand, here's another example from a more complicated template.

Here, I use regular expressions to extract two numbers (defined as 'f' and 's') from a column, do arithmetic on them, and then define the results of the math as 'newpercent.' This lets me use it further down the template.

f = re($#chapters, '(.*)/.*', '\1');
s = re($#chapters, '.*/(.*)', '\1');
newpercent = round(multiply ((f / s), 100));

GPM if-then templates:

if "^Fallout$" inlist f then 'fallout.png:' fi

This is an if-then template. If 'Fallout' is found in the list f, then output 'fallout.png:' and finish.

You can also throw elses in there:

if "^Fallout$" inlist f then 'fallout.png:' else 'null.png' fi

Here, if 'Fallout' is found, it'll output 'fallout.png'; otherwise, it'll output 'null.png:' and then finish.

Concatenation:

You notice that all the if-then templates are wrapped in a strcat() and that there's a comma at the end of each one.

This means that anything inside it will all be concatenated together. So if I have a book with "Fallout" and "Half-Life" in the column, instead of only displaying the first one, it'll output "fallout.png:halflife.png:" (and display both of them).

[chaley]

There are hundreds of examples in the thread "Plugboard, template, and custom composite column recipes". I suggest you start with the last post and work backwards.

[Fynjisx]

Originally Posted by ownedbycats

f = re($#chapters, '(.*)/.*', '\1');
s = re($#chapters, '.*/(.*)', '\1');
newpercent = round(multiply ((f / s), 100));

.

explain how you made the number of read pages in books? How to make a column with the format i/pages, with the ability to extract i and pages separately? You will have to modify i manually every time, reading the pdf format

[ownedbycats]

Originally Posted by Fynjisx

explain how you made the number of read pages in books? How to make a column with the format i/pages, with the ability to extract i and pages separately? You will have to modify i manually every time, reading the pdf format

It isn't for pages. I use it to generate a new percent read after a fanfiction updates. It requires a very specific library/plugin setup that it wouldn't be helpful for most people.

However, I do have an Action Chain that'll let you input the current page number into a dialog, compare it against #pagecount, and then populate #percentread from it. I use it for physical books, or ones in PDF format.

Here's the template.

program:
	totalpage = $#pagecount;
	currentpage = globals(Current_Page=1);
	newpercent = round(multiply ((currentpage / totalpage), 100));

Note that globals(Current_Page=1) is the number inputted during the runtime of the action chain and it won't work outside the context of the chain (or at least it won't do anything useful).

However, if you want to play around with it: Open the Template Tester and replace the 'globals' bit with various numbers. (Don't forget the semicolon.) You'll see the value change depending on the #pagecount column of the selected books and whatever you define as currentpage.

[Fynjisx]

Originally Posted by ownedbycats

Here's part of a somewhat simple GPM template made to display icons for various fanfics rather than a zillion different column icon rules:

program:
   strcat(
		if "^Fallout$" inlist f then 'fallout.png:' fi,
		if "^Half-Life$" inlist f then 'halflife.png:' fi,
		if "^(Mass Effect Trilogy|Mass Effect: Andromeda)$" inlist f then 'masseffect.png:' fi,
		if "^The Elder Scrolls$" inlist f then 'theelderscrolls.png:' fi,
		if "^Pokémon$" inlist f then 'pokemon.png:' fi,		
		if "^Portal$" inlist f then 'portal.png:' fi,
   )

but it can be done through the GUI interface!