module I18n::Backend::Flatten

This module contains several helpers to assist flattening translations. You may want to flatten translations for:

1) speed up lookups, as in the Memoize backend;
2) In case you want to store translations in a data store, as in ActiveRecord backend;

You can check both backends above for some examples. This module also keeps all links in a hash so they can be properly resolved when flattened.

Constants

FLATTEN_SEPARATOR
SEPARATOR_ESCAPE_CHAR

Public Class Methods

normalize_flat_keys (locale, key, scope, separator)

normalize_keys the flatten way. This method is significantly faster and creates way less objects than the one at I18n.normalize_keys. It also handles escaping the translation keys.

# File lib/i18n/backend/flatten.rb, line 20
def self.normalize_flat_keys(locale, key, scope, separator)
  keys = [scope, key]
  keys.flatten!
  keys.compact!

  separator ||= I18n.default_separator

  if separator != FLATTEN_SEPARATOR
    from_str = "#{FLATTEN_SEPARATOR}#{separator}"
    to_str = "#{SEPARATOR_ESCAPE_CHAR}#{FLATTEN_SEPARATOR}"

    keys.map! { |k| k.to_s.tr from_str, to_str }
  end

  keys.join(".")
end

Public Instance Methods

flatten_keys (hash, escape, prev_key=nil) { |curr_key, value| ... }

Flatten keys for nested Hashes by chaining up keys:

>> { "a" => { "b" => { "c" => "d", "e" => "f" }, "g" => "h" }, "i" => "j"}.wind
=> { "a.b.c" => "d", "a.b.e" => "f", "a.g" => "h", "i" => "j" }

# File lib/i18n/backend/flatten.rb, line 59
def flatten_keys(hash, escape, prev_key=nil, &block)
  hash.each_pair do |key, value|
    key = escape_default_separator(key) if escape
    curr_key = [prev_key, key].compact.join(FLATTEN_SEPARATOR).to_sym
    yield curr_key, value
    flatten_keys(value, escape, curr_key, &block) if value.is_a?(Hash)
  end
end

flatten_translations (locale, data, escape, subtree)

Receives a hash of translations (where the key is a locale and the value is another hash) and return a hash with all translations flattened.

Nested hashes are included in the flattened hash just if subtree is true and Symbols are automatically stored as links.

# File lib/i18n/backend/flatten.rb, line 74
def flatten_translations(locale, data, escape, subtree)
  hash = {}
  flatten_keys(data, escape) do |key, value|
    if value.is_a?(Hash)
      hash[key] = value if subtree
    else
      store_link(locale, key, value) if value.is_a?(Symbol)
      hash[key] = value
    end
  end
  hash
end

links ()

Store flattened links.

# File lib/i18n/backend/flatten.rb, line 50
def links
  @links ||= I18n.new_double_nested_cache
end

normalize_flat_keys (locale, key, scope, separator)

Shortcut to I18n::Backend::Flatten.normalize_flat_keys and then resolve_links.

# File lib/i18n/backend/flatten.rb, line 44
def normalize_flat_keys(locale, key, scope, separator)
  key = I18n::Backend::Flatten.normalize_flat_keys(locale, key, scope, separator)
  resolve_link(locale, key)
end

Protected Instance Methods

resolve_link (locale, key)

# File lib/i18n/backend/flatten.rb, line 93
def resolve_link(locale, key)
  key, locale = key.to_s, locale.to_sym
  links = self.links[locale]

  if links.key?(key)
    links[key]
  elsif link = find_link(locale, key)
    store_link(locale, key, key.gsub(*link))
  else
    key
  end
end

store_link (locale, key, link)

# File lib/i18n/backend/flatten.rb, line 89
def store_link(locale, key, link)
  links[locale.to_sym][key.to_s] = link.to_s
end