Class: Serega::SeregaUtils::ParamsCount

Inherits:
Object
  • Object
show all
Defined in:
lib/serega/utils/params_count.rb

Overview

Utility to count regular parameters of callable object

Class Method Summary collapse

Class Method Details

.call(object, max_count:) ⇒ Integer

Count parameters for callable object

Parameters:

  • object (#call) —

    callable object

Returns:

  • (Integer) —

    count of regular parameters



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# File 'lib/serega/utils/params_count.rb', line 23

def call(object, max_count:)
  # Procs (but not lambdas) can accept all provided parameters
  parameters = object.is_a?(Proc) ? object.parameters : object.method(:call).parameters
  return 1 if parameters[0] == NO_NAMED_REST_PARAM
  return max_count if object.is_a?(Proc) && !object.lambda?

  count = 0

  # If all we have is no-name *rest parameters, then we assume we need to provide
  # 1 argument. It is now always correct, but in serialization context it's most common that
  # only one argument is needed.
  parameters.each do |parameter|
    next if parameter == NO_NAMED_REST_PARAM # Workaround for procs like :odd?.to_proc
    param_type = parameter[0]

    case param_type
    when :req then count += 1
    when :opt then count += 1 if count < max_count
    when :rest then count += max_count - count if max_count > count
    end # else :opt, :keyreq, :key, :keyrest, :block - do nothing
  end

  count
end