Module: ActiveSupport::CachingTools::HashCaching

Module | ActiveSupport::CachingTools::HashCaching
In: | lib/active_support/caching_tools.rb

Provide shortcuts to simply the creation of nested default hashes. This pattern is useful, common practice, and unsightly when done manually.

### Methods

hash_cache

### Public Instance methods

hash_cache(method_name, options = {})

Dynamically create a nested hash structure used to cache calls to `method_name` The cache method is named +#{method_name}_cache+ unless :as => :alternate_name is given.

The hash structure is created using nested Hash.new. For example:

      def slow_method(a, b) a ** b end

can be cached using hash_cache :slow_method, which will define the method slow_method_cache. We can then find the result of a ** b using:

      slow_method_cache[a][b]

The hash structure returned by slow_method_cache would look like this:

      Hash.new do |as, a|
        as[a] = Hash.new do |bs, b|
          bs[b] = slow_method(a, b)
        end
      end

The generated code is actually compressed onto a single line to maintain sensible backtrace signatures.

[Validate]