class SyntaxTree::Parser

def on_symbols_beg(value)

on_symbols_beg: (String value) -> SymbolsBeg
:call-seq: 
def on_symbols_beg(value)
  node =
    SymbolsBeg.new(
      value: value,
      location:
        Location.token(
          line: lineno,
          char: char_pos,
          column: current_column,
          size: value.size
        )
    )
  tokens << node
  node
end