postmodern/command_kit.rb

# frozen_string_literal: true

require 'strscan'

module CommandKit
  #
  # A very simple inflector.
  #
  # @note
  #   If you need something more powerful, checkout
  #   [dry-inflector](https://dry-rb.org/gems/dry-inflector/0.1/)
  #
  # @api semipublic
  #
  module Inflector
    #
    # Removes the namespace from a constant name.
    #
    # @param [#to_s] name
    #   The constant name.
    #
    # @return [String]
    #   The class or module's name, without the namespace.
    #
    def self.demodularize(name)
      name.to_s.split('::').last
    end

    #
    # Converts a CamelCased name to an under_scored name.
    #
    # @param [#to_s] name
    #   The CamelCased name.
    #
    # @return [String]
    #   The resulting under_scored name.
    #
    # @raise [ArgumentError]
    #   The given string contained non-alpha-numeric characters.
    #
    def self.underscore(name)
      scanner    = StringScanner.new(name.to_s)
      new_string = String.new

      until scanner.eos?
        if (separator = scanner.scan(/[_-]+/))
          new_string << ('_' * separator.length)
        else
          if (capitalized = scanner.scan(/[A-Z][a-z\d]+/))
            new_string << capitalized
          elsif (uppercase = scanner.scan(/[A-Z][A-Z\d]*(?=[A-Z_-]|$)/))
            new_string << uppercase
          elsif (lowercase = scanner.scan(/[a-z][a-z\d]*/))
            new_string << lowercase
          else
            raise(ArgumentError,"cannot convert string to underscored: #{scanner.string.inspect}")
          end

          if (separator = scanner.scan(/[_-]+/))
            new_string << ('_' * separator.length)
          elsif !scanner.eos?
            new_string << '_'
          end
        end
      end

      new_string.downcase!
      new_string
    end

    #
    # Replaces all underscores with dashes.
    #
    # @param [#to_s] name
    #   The under_scored name.
    #
    # @return [String]
    #   The dasherized name.
    #
    def self.dasherize(name)
      name.to_s.tr('_','-')
    end

    #
    # Converts an under_scored name to a CamelCased name.
    #
    # @param [String] name
    #   The under_scored name.
    #
    # @return [String]
    #   The CamelCased name.
    #
    # @raise [ArgumentError]
    #   The given under_scored string contained non-alpha-numeric characters.
    #
    def self.camelize(name)
      scanner    = StringScanner.new(name.to_s)
      new_string = String.new

      until scanner.eos?
        if (word = scanner.scan(/[A-Za-z\d]+/))
          word.capitalize!
          new_string << word
        elsif (numbers = scanner.scan(/[_-]\d+/))
          new_string << "_#{numbers[1..]}"
        elsif scanner.scan(/[_-]+/)
          # skip
        elsif scanner.scan(%r{/})
          new_string << '::'
        else
          raise(ArgumentError,"cannot convert string to CamelCase: #{scanner.string.inspect}")
        end
      end

      new_string
    end
  end
end