pretty_print_infix_bad.cpp

std::string print_infix_op_bad(op<add_tag, std::string> const& e)
{
   return boost::algorithm::join(e.rands(), " + ");
}

std::string with_parens(std::string const& s)
{
   return std::string("(") + s + ")";
}

std::string print_infix_op_bad(op<mul_tag, std::string> const& e)
{
   return boost::algorithm::join(e.rands() | transformed(with_parens), " * ");
}

std::string print_infix_bad(expression_r<std::string> const& e)
{
   if (auto* o = get_as_add(e)) return print_infix_op_bad(*o);
   if (auto* o = get_as_mul(e)) return print_infix_op_bad(*o);
   if (auto* i = get_as_cst(e)) return std::to_string(*i);
   if (auto* v = get_as_var(e)) return *v;
   throw_missing_pattern_matching_clause();
}