Class: Guardrails::TokenMatcher

Inherits:
Object
  • Object
show all
Defined in:
lib/guardrails/token_matcher.rb

Defined Under Namespace

Classes: Match

Constant Summary collapse

NEAR_MATCH_THRESHOLD = 
4

Instance Method Summary collapse

Constructor Details

#initialize(tokens, near_match_threshold: NEAR_MATCH_THRESHOLD) ⇒ TokenMatcher

Returns a new instance of TokenMatcher.



11
12
13
14
15
 
# File 'lib/guardrails/token_matcher.rb', line 11

def initialize(tokens, near_match_threshold: NEAR_MATCH_THRESHOLD)
  @tokens = tokens
  @lookup = tokens.to_h { |t| [HexNormalizer.normalize(t.value), t] }
  @near_match_threshold = near_match_threshold
end

Instance Method Details

#match(value) ⇒ Object 



17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
 
# File 'lib/guardrails/token_matcher.rb', line 17

def match(value)
  return nil if value.nil?

  exact = @lookup[HexNormalizer.normalize(value)]
  return Match.new(token: exact, kind: :exact, distance: 0) if exact

  best = nil
  best_distance = @near_match_threshold + 1
  @tokens.each do |t|
    d = HexNormalizer.distance(value, t.value)
    next unless d
    next if d.zero?

    if d < best_distance
      best = t
      best_distance = d
    end
  end
  return nil unless best

  Match.new(token: best, kind: :near, distance: best_distance)
end