With this refactor, I'm adding documentation and favoring using a common
method that wasn't available at the time of implementation.
In [this commit][1] we had logic that said "if we have a singular tag
use the cache" otherwise use the join. At that time, the implementation
of [Article.cached_tag_with][previous] was as follows, allowing only a
singular tag:
```ruby
scope :cached_tagged_with, ->(tag) { where("cached_tag_list ~* ?",
"^#{tag},| #{tag},|, #{tag}$|^#{tag}$") }
```
The [current implementation][current], as of writing this, allows for
multiple tags and is as follows:
```ruby
scope :cached_tagged_with, lambda { |tag|
case tag
when String, Symbol
# In Postgres regexes, the [[:<:]] and [[:>:]] are equivalent to "start of
# word" and "end of word", respectively. They're similar to `\b` in Perl-
# compatible regexes (PCRE), but that matches at either end of a word.
# They're more comparable to how vim's `\<` and `\>` work.
where("cached_tag_list ~ ?", "[[:<:]]#{tag}[[:>:]]")
when Array
tag.reduce(self) { |acc, elem| acc.cached_tagged_with(elem) }
when Tag
cached_tagged_with(tag.name)
else
raise TypeError, "Cannot search tags for: #{tag.inspect}"
end
}
```
Given that we are content to use the cached tag in the singular tag
case, it seems safe to say that we're comfortable using it in the
multiple tag case.
[1]:af5a391429 (diff-24503fd25ed68e6ebceee4951bc4f9b255b197278d4aa9d86ef9d5afe3f26bea)
[previous]:af5a391429/app/models/article.rb (L151)
[current]:98e97e7aa8/app/models/article.rb (L212-L227)
c75dd69d09