class SyntaxTree::Parser

def on_for(index, collection, statements)

) -> For
Statements statements
untyped collection,
(MLHS | VarField) value,
on_for: (
:call-seq: 
def on_for(index, collection, statements)
  beginning = consume_keyword(:for)
  in_keyword = consume_keyword(:in)
  ending = consume_keyword(:end)
  delimiter =
    find_keyword_between(:do, collection, ending) ||
      find_token_between(Semicolon, collection, ending)
  tokens.delete(delimiter) if delimiter
  start_char =
    find_next_statement_start((delimiter || collection).location.end_char)
  statements.bind(
    self,
    start_char,
    start_char -
      line_counts[(delimiter || collection).location.end_line - 1].start,
    ending.location.start_char,
    ending.location.start_column
  )
  if index.is_a?(MLHS)
    comma_range = index.location.end_char...in_keyword.location.start_char
    index.comma = true if source[comma_range].strip.start_with?(",")
  end
  For.new(
    index: index,
    collection: collection,
    statements: statements,
    location: beginning.location.to(ending.location)
  )
end