formula_solver.py 文件源码

def abstract_brackets(formula, variables_re=''):
  lwt = split_formula(formula)
  new_variables = {}
  while lwt:
    substitute = no_re_matches(combine_re_expressions(
        itertools.chain((variables_re,), new_variables.keys())
    ))
    formula = lwt['leading'] + substitute + lwt['trailing']
    new_variables[substitute] = lwt['within']
    lwt = split_formula(formula)
  if formula in new_variables.keys():
    # incase of extranous brackets
    return abstract_brackets(new_variables[formula], variables_re)
  # return [formula, new_variables]
  return namedtuple('abstract_brackets', ('formula', 'new_variables'))(formula, new_variables)


# splits formula into 2 parts (leading and trailing) where the operator (from settings.order_of_operations) with the lowest priority is
# if there are no operators in formula returns None