fields.py 文件源码

def _rebuild_expr(self, expr, mapping):
        domain = self.domain

        def _rebuild(expr):
            generator = mapping.get(expr)

            if generator is not None:
                return generator
            elif expr.is_Add:
                return reduce(add, list(map(_rebuild, expr.args)))
            elif expr.is_Mul:
                return reduce(mul, list(map(_rebuild, expr.args)))
            elif expr.is_Pow and expr.exp.is_Integer:
                return _rebuild(expr.base)**int(expr.exp)
            else:
                try:
                    return domain.convert(expr)
                except CoercionFailed:
                    if not domain.has_Field and domain.has_assoc_Field:
                        return domain.get_field().convert(expr)
                    else:
                        raise

        return _rebuild(sympify(expr))