class SyntaxTree::Parser

def on_while(predicate, statements)

on_while: (untyped predicate, Statements statements) -> WhileNode
:call-seq: 
def on_while(predicate, statements)
  beginning = consume_keyword(:while)
  ending = consume_keyword(:end)
  delimiter =
    find_keyword_between(:do, predicate, statements) ||
      find_token_between(Semicolon, predicate, statements)
  tokens.delete(delimiter) if delimiter
  # Update the Statements location information
  start_char =
    find_next_statement_start((delimiter || predicate).location.end_char)
  statements.bind(
    self,
    start_char,
    start_char - line_counts[predicate.location.end_line - 1].start,
    ending.location.start_char,
    ending.location.start_column
  )
  WhileNode.new(
    predicate: predicate,
    statements: statements,
    location: beginning.location.to(ending.location)
  )
end