Module: Ramda::Internal::Dispatchable

Included in:
Function, List
Defined in:
lib/ramda/internal/dispatchable.rb

Overview

Dispatchable rubocop:disable Performance/CaseWhenSplat rubocop:disable Metrics/MethodLength rubocop:disable Style/GuardClause

Instance Method Summary collapse

Instance Method Details

#dispatchable(method_names, described_types, xf = nil, &fn) ⇒ Object

Returns a function that dispatches with different strategies based on the

object in list position (last argument). If it is an array, executes [fn].
Otherwise, if it has a  function with [methodname], it will execute that
function (functor case). Otherwise, if it is a transformer, uses transducer
[xf] to return a new transformer (transducer case). Otherwise, it will
default to executing [fn].

@private
- @param {Array[Symbol]|Symbol} method_names property to check for a custom implementation
- @param {Array[Class]|Class} described_types a list of type with default behaviour
- @param {Function} xf transducer to initialize if object is transformer
- @param {Function} fn default ramda implementation
- @return {Function} A function that dispatches on object in list position



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# File 'lib/ramda/internal/dispatchable.rb', line 22

def dispatchable(method_names, described_types, xf = nil, &fn)
  method_names = Array(method_names)

  FunctionWithArity.call(fn.arity) do |*args, xs|
    case xs
    when *described_types # default behaviour
      yield(*args, xs)

    when Proc # transducer behaviour
      xf.call(*args, xs)

    else # method dispatch behaviour
      method_name = method_names.find { |name| xs.respond_to?(name) }

      if method_name
        xs.public_send(method_name, *args)
      else
        raise ArgumentError, "Unexpected type #{xs.class} in method: #{method_name}"
      end
    end
  end
end