Design an intuitive term/taxonomy/category/tag interface

[pkarl]

When I think about this problem, I ask myself: What is the simplest way to tell WordPress that I want a particular cross-section of content decorated with tags.

There are a few things that come to mind immediately:

1. Categories are bullshit, so if anything, a ->category() method will just be an alias to something else (similar to their role in WP)
2. Terms are unique more often than they belong to multiple taxonomies, so let's build for unique-ness but accommodate multiple term hits
3. The term vs. taxonomy vs. tax_query nomenclature is the thinking that created this messy interface to begin with. I think if we can create a simple interface (like ->tag()) that accepts a variety of inputs, we'll be better off.
4. this doesn't account for grabbing all posts within a taxonomy, I think that warrants a sep interface (->taxonomy('some-tax-name'))

So here's a first draft of a few simple scenarios:

<?php

// fetch all posts tagged with 'pineapple'
$qq->tag( 'pineapple' )->go();

// also works with term_id
$qq->tag( 42 )->go();

// fetch all posts tagged with 'pineapple' and 'cucumber'
$qq->tag( ['pineapple', 'cucumber'] )->go(); // defaults to AND

// fetch all posts tagged with 'pineapple' EXCEPT those tagged with 'cucumber'
$qq->tag( ['pineapple', '-cucumber'] )->go();
$qq->tag( [42, '-cucumber'] )->go();
$qq->tag( [42, -13] )->go();

// fetch all posts tagged with 'pineapple' OR 'cucmber'
$qq->tag( ['pineapple', 'cucumber'], 'OR' )->go();

// if you want to specify a taxonomy for some reason, you can
$qq->tag( ['sea_creatures'=>['chicken', 'tuna']] )->go();

There will be a challenge executing some of these with WP_Query (I'm not sure if the select this, but not this will work with tax_query).

[pkarl]

I guess just to be clear, here are the scenarios in order of (what I'm guessing) is most frequent -> least frequent:

• fetch all posts by a given tag
• fetch all posts that match multiple tags (with an AND or OR relationship)
• fetch all posts within a taxonomy
• fetch all posts from multiple tags that live in diff. taxonomies
• fill in results with posts tagged sometag up to N results
• fetch all posts that match one tag while excluding another

[jarednova]

@pkarl those scenarios make sense to me. I'm pretty down with the API with the exception of the tag nomenclature. As you point out: category is all smoke-and-mirrors. Just another taxonomy. The only modification I'd make is using term in place of tag.

The scenarios make sense to me. I've been mulling it over and can't really think of other circumstances.

[pkarl]

@jarednova since it accepts a variety of inputs (categories, terms, taxonomy names) in various forms (arrays, strings, ints), I wanted to come up with a generic interface for all of these things. tag doesn't feel exactly right, but it serves the purpose of avoiding a name that already exists in the messy WP nomenclature while still covering the conceptual bases.

I'd prefer to leave term, category and taxonomy, etc. as aliases to this generic method.

When we see scenarios like $qq->term( ['fish'=>['bass', 'fluke'], ['pets'=>['cat', 'dog', 'fish']], 'AND' )->go() I'd do a double take.

That said, I'm not married to the idea of a SINGLE interface for all this. I may be asking too much of a single method to carry the weight of WP's entire crazy taxonomy system. @jarednova on a scale of "one method, complex args" to "complex methods, simple args", what feels right for human-friendly WP taxonomy queries?

[pkarl]

Based on an IRL conversation with @jarednova here's where things stand:

• There should be methods (even if they're aliases) for tag, category, taxonomy, and term
• For complex taxonomy queries, we'll offer a method called tax() which will replace tag in the examples above
• tag-based exclusions are more important than I realized so moar tests!

[pkarl]

Actually, I think this is as solid as the direction is going to get for alpha. Closing!