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.

Methods
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Constants
SEPARATOR_ESCAPE_CHAR = "\001"
 
FLATTEN_SEPARATOR = "."
 
Class Public 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.

Source: show | on GitHub 

# File activesupport/lib/active_support/vendor/i18n-0.4.1/i18n/backend/flatten.rb, line 18
def self.normalize_flat_keys(locale, key, scope, separator)
  keys = [scope, key].flatten.compact
  separator ||= I18n.default_separator
  if separator != FLATTEN_SEPARATOR
    keys.map! do |k|
      k.to_s.tr("#{FLATTEN_SEPARATOR}#{separator}",
        "#{SEPARATOR_ESCAPE_CHAR}#{FLATTEN_SEPARATOR}")
    end
  end
  keys.join(".")
end
Instance Public methods
flatten_keys(hash, escape, prev_key=nil, &block)

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" }

Source: show | on GitHub 

# File activesupport/lib/active_support/vendor/i18n-0.4.1/i18n/backend/flatten.rb, line 54
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.

Source: show | on GitHub 

# File activesupport/lib/active_support/vendor/i18n-0.4.1/i18n/backend/flatten.rb, line 69
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

Store flattened links.

Source: show | on GitHub

normalize_flat_keys(locale, key, scope, separator)

Shortcut to ::normalize_flat_keys and then resolve_links.

Source: show | on GitHub 

# File activesupport/lib/active_support/vendor/i18n-0.4.1/i18n/backend/flatten.rb, line 39
def normalize_flat_keys(locale, key, scope, separator)
  key = I18n::Backend::Flatten.normalize_flat_keys(locale, key, scope, separator)
  resolve_link(locale, key)
end
Instance Protected methods

Source: show | on GitHub

Source: show | on GitHub