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Paginator::Lite is a Perl module that provides a simple way to get some informations about a collection of data (database rows, sometimes) that may be used to make pagination components.

When you handle collections of data, sometimes you don’t want to retrieve or display all items at once. If you are working with a database, its easy retrieve only a portion of rows at a time using the keywords LIMIT and OFFSET.

The annoying problem, is how to create navigation for all ‘pages’ of data.

On my applications, normally I know the total number of rows, how much rows I want to display and what is the current page. So, since the first and last pages are relatively fixed, I can make a loop that iterates from first (normally 1) page until the last page and create the navigation.

This approach works fine since I don’t have too many pages to display. When the number of pages grow up, I get too many components polluting the interface. In this case, I need paginate the paginator!

For this, I thought in the concept of frame. A frame is a subset of pagination components that are visible at this moment. So, instead of a thousand of buttons or links, I have a ‘window’ with only some of them. Something like the pagination at bottom of Google Search page, that displays only 20 page each time. Additionally, the current page is in middle of frame always that is possible. I like this!

So, given the total number of pages (or the number of items and the number of items per page), the number of the current page and the frame size, I want a subset of pages (the number of each page) on which the current page is in the middle of frame, the first page on frame is something like (current – frame_size / 2) and the last page on frame is something like (current + frame_size / 2). Additionally I want know which is the first page (always 1), last page, previous page and next page.

With these informations, I can create a view like this:

(first) (prev) 4 5 6 (7) 8 9 10 (next) (last)

Usually, each time we need draw the paginator, we need calculate these values and check them if they are not out of range. This module does exactly this.

Note: This module don’t generates html. It only helps you to do this, providing you with information about how to generate a simple view.