method

constantize

v6.1.7.7 - Show latest stable - 0 notes - Class: ActiveSupport::Inflector

constantize(camel_cased_word) public

Tries to find a constant with the name specified in the argument string.

constantize('Module')   # => Module
constantize('Foo::Bar') # => Foo::Bar

The name is assumed to be the one of a top-level constant, no matter whether it starts with “::” or not. No lexical context is taken into account:

C = 'outside'
module M
  C = 'inside'
  C                # => 'inside'
  constantize('C') # => 'outside', same as ::C
end

NameError is raised when the name is not in CamelCase or the constant is unknown.

Show source

# File activesupport/lib/active_support/inflector/methods.rb, line 271
    def constantize(camel_cased_word)
      if camel_cased_word.blank? || !camel_cased_word.include?("::")
        Object.const_get(camel_cased_word)
      else
        names = camel_cased_word.split("::")

        # Trigger a built-in NameError exception including the ill-formed constant in the message.
        Object.const_get(camel_cased_word) if names.empty?

        # Remove the first blank element in case of '::ClassName' notation.
        names.shift if names.size > 1 && names.first.empty?

        names.inject(Object) do |constant, name|
          if constant == Object
            constant.const_get(name)
          else
            candidate = constant.const_get(name)
            next candidate if constant.const_defined?(name, false)
            next candidate unless Object.const_defined?(name)

            # Go down the ancestors to check if it is owned directly. The check
            # stops when we reach Object or the end of ancestors tree.
            constant = constant.ancestors.inject(constant) do |const, ancestor|
              break const    if ancestor == Object
              break ancestor if ancestor.const_defined?(name, false)
              const
            end

            # owner is in Object, so raise
            constant.const_get(name, false)
          end
        end
      end
    end

constantize

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