1. unary expressions (prefix operations)
2. multiplicative * / %
3. additive + -
4. other
5. assignment =
6. comma ,

Here is the problem I am facing: In Heron there are no predefined operators. Any sequence of operator characters is in fact a legal operator. All operators map to a specifically named member function of the left hand value.

An example of a problem with just following C++ operator precedence rules is that an overloaded pipe operator (|) might actually mean to create a pipe and not bitwise or. Even > could have multiple meanings like redirect output to a file or greater than. Giving it a specific precedence based on usage of bitwise or is not a good idea. What about entirely new operators, like &&= which means assignment boolean and. It should be at the same level as the other assignment operators. Anyway the list of complications goes on and on. I think beyond the simple arithmetic precedence rules, it is best if I rely on disamibguation rules.

Maybe there is another way that everyone can be happy: I wonder if there there is an elegant way to implement precedence directly within a language? Maybe there would be an expression reordering step, that is controllable from code. Perhaps something inspired by expression template machinery? Perhaps operators could map to types or function pointers? I am open to new ideas here.