Module: Lang::Tag::Lookup

Included in:
Grandfathered, Langtag, Privateuse
Defined in:
lib/lang/tag/lookup.rb

Overview

Lookup. RFC 4647, Section 3.4.

Instance Method Summary collapse

Instance Method Details

#in?(range) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/lang/tag/lookup.rb', line 46

def in?(range)
  range = Composition === range ? range.composition : range.to_str.downcase
  return true if composition == range
  range.index(composition) == 0
end

#lookup_candidates(min_subtags_count = 1) ⇒ Object

– RFC 4647, Section 3.4

In the lookup scheme, the language range is progressively truncated from the end until a matching language tag is located. Single letter or digit subtags (including both the letter ‘x’, which introduces private-use sequences, and the subtags that introduce extensions) are removed at the same time as their closest trailing subtag. For example, starting with the range “zh-Hant-CN-x-private1-private2” (Chinese, Traditional script, China, two private-use tags) the lookup progressively searches for content as shown below:

Example of a Lookup Fallback Pattern

Range to match: zh-Hant-CN-x-private1-private2

  1. zh-Hant-CN-x-private1-private2

  2. zh-Hant-CN-x-private1

  3. zh-Hant-CN

  4. zh-Hant

  5. zh

  6. (default)

++



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# File 'lib/lang/tag/lookup.rb', line 34

def lookup_candidates(min_subtags_count = 1)
  subtags = to_a
  return nil if min_subtags_count < 1 || subtags.size < min_subtags_count

  candidates = []
  for i in (min_subtags_count - 1)..(subtags.size - 1) do
    next if subtags[i].size == 1
    candidates.unshift subtags[0..i].join(HYPHEN)
  end
  candidates
end