Class: Dentaku::Tokenizer

Inherits:
Object
  • Object
show all
Defined in:
lib/dentaku/tokenizer.rb

Constant Summary collapse

LPAREN = 
TokenMatcher.new(:grouping, :open)
RPAREN = 
TokenMatcher.new(:grouping, :close)

Instance Attribute Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#aliases ⇒ Object (readonly)

Returns the value of attribute aliases.



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# File 'lib/dentaku/tokenizer.rb', line 8

def aliases
  @aliases
end

Instance Method Details

#alias_regex ⇒ Object 



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# File 'lib/dentaku/tokenizer.rb', line 97

def alias_regex
  values = @aliases.values.flatten.join('|')
  /(?<=\p{Punct}|[[:space:]]|\A)(#{values})(?=\()/i
end

#last_token ⇒ Object 



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# File 'lib/dentaku/tokenizer.rb', line 58

def last_token
  @tokens.last
end

#replace_aliases(string) ⇒ Object 



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# File 'lib/dentaku/tokenizer.rb', line 83

def replace_aliases(string)
  return string unless @aliases.any?

  string.gsub!(alias_regex) do |match|
    match_regex = /^#{Regexp.escape(match)}$/i

    @aliases.detect do |(_key, aliases)|
      !aliases.grep(match_regex).empty?
    end.first
  end

  string
end

#strip_comments(input) ⇒ Object 



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# File 'lib/dentaku/tokenizer.rb', line 79

def strip_comments(input)
  input.gsub(/\/\*[^*]*\*+(?:[^*\/][^*]*\*+)*\//, '')
end

#tokenize(string, options = {}) ⇒ Object 



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# File 'lib/dentaku/tokenizer.rb', line 13

def tokenize(string, options = {})
  @nesting = 0
  @tokens  = []
  @aliases = options.fetch(:aliases, global_aliases)
  input    = strip_comments(string.to_s.dup)
  input    = replace_aliases(input)

  scanner_options = {
    case_sensitive: options.fetch(:case_sensitive, false),
    raw_date_literals: options.fetch(:raw_date_literals, true)
  }

  # Hoist the scanner list out of the per-position loop. The previous code
  # rebuilt this Array (via Hash#select + .values) on every advance, which
  # was a significant chunk of tokenize allocations.
  scanners = TokenScanner.scanners(scanner_options)

  ss = StringScanner.new(input)

  until ss.eos?
    last_token = @tokens.last
    scanned = false

    scanners.each do |scanner|
      result = scanner.scan_at(ss, last_token)
      next unless result

      if result.is_a?(Array)
        result.each { |t| handle_token(t, ss) }
      else
        handle_token(result, ss)
      end

      scanned = true
      break
    end

    fail! :parse_error, at: ss.rest unless scanned
  end

  fail! :too_many_opening_parentheses if @nesting > 0

  @tokens
end