Add functions to partition (page) slices

[raoulb]

I propose to add some new functionality to split a slice of pages into chunks of a given fixed length plus possibly a shorter remainder.

Use cases include listings and multi-column row-based tabular layouts.

As far as I know there is right now no such functionality exposed to the templates API. The new functions should be straight-forward to use compared to a custom implementation by lower-level template primitives. It is expected to be faster and less error-prone too and, as a built-in readily available to all Hugo users.

This topic came up first with the bug report #11553 and it solves the issue raised there.
That bug is related to #11131 which broke a custom template-based implementation.

An implementation can be found at PR #12661 (resp. the branch https://github.com/raoulb/hugo/tree/partition).

With this post I'd like to start the discussion on what needs to be changed to get this functionality merged.

[jmooring]

Please provide an example of how you would use the new template function in a template (e.g., /layouts/_default/list.html).

[bep]

Thanks for this; this needs to put on hold for a little. I need to think a little about the "future" of the collections package. This package was implemented before Go generics, and I don't want to add more complexity/generics code if we don't need to. For funcs that operate on slices only, e.g. Partition, I don't see why we cannot just delegate to something ala:

https://pkg.go.dev/github.com/bep/helpers@v0.5.0/slicehelpers

[raoulb]

Please provide an example of how you would use the new template function in a template (e.g., /layouts/_default/list.html).

I made a minimal example which can be found here

An envisioned use case might look like:

  {{ range $.Site.RegularPages | partition 3 | first 2 }}
    <h3>Some heading</h3>
    <div>
      {{ partial "fancy.html" . }}
    </div>
  {{ end }}

where the fancy.html partial might implement a complex layout like a slideshow or similar.

The minimal example here will look like:

[raoulb]

Thanks for this; this needs to put on hold for a little. I need to think a little about the "future" of the collections package. This package was implemented before Go generics, and I don't want to add more complexity/generics code if we don't need to. For funcs that operate on slices only, e.g. Partition, I don't see why we cannot just delegate to something ala:

https://pkg.go.dev/github.com/bep/helpers@v0.5.0/slicehelpers

I'd be fine with skipping the collections part (i.e. partition) and for now just add the PartitionWith function on Pages.

[raoulb]

For funcs that operate on slices only, e.g. Partition, I don't see why we cannot just delegate to something ala:

https://pkg.go.dev/github.com/bep/helpers@v0.5.0/slicehelpers

I guess we can? I'd try to implement this once we decide to use that dependency.