Method: Puppet::Pops::Parser::InterpolationSupport#interpolate_dq

Defined in:
lib/puppet/pops/parser/interpolation_support.rb

#interpolate_dq ⇒ Object

This is the starting point for a double quoted string with possible interpolation The structure mimics that of the grammar. The logic is explicit (where the former implementation used parameters/structures) given to a generic handler. (This is both easier to understand and faster).



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# File 'lib/puppet/pops/parser/interpolation_support.rb', line 17

def interpolate_dq
  scn = @scanner
  ctx = @lexing_context
  before = scn.pos
  # skip the leading " by doing a scan since the slurp_dqstring uses last matched when there is an error
  scn.scan(/"/)
  value,terminator = slurp_dqstring()
  text = value
  after = scn.pos
  loop do
    case terminator
    when '"'
      # simple case, there was no interpolation, return directly
      return emit_completed([:STRING, text, scn.pos-before], before)
    when '${'
      count = ctx[:brace_count]
      ctx[:brace_count] += 1
      # The ${ terminator is counted towards the string part
      enqueue_completed([:DQPRE, text, scn.pos-before], before)
      # Lex expression tokens until a closing (balanced) brace count is reached
      enqueue_until count
      break
    when '$'
      varname = scn.scan(PATTERN_VARIABLE)
      if varname
        # The $ is counted towards the variable
        enqueue_completed([:DQPRE, text, after-before-1], before)
        enqueue_completed([:VARIABLE, varname, scn.pos - after + 1], after - 1)
        break
      else
        # false $ variable start
        text += terminator
        value,terminator = slurp_dqstring()
        text += value
        after = scn.pos
      end
    end
  end
  interpolate_tail_dq
  # return the first enqueued token and shift the queue
  @token_queue.shift
end