I remember reading a Perl 6 design document back in the day that made a convincing argument that operator precedence should be a partial instead of a total orde

I remember reading a Perl 6 design document back in the day that made a convincing argument that operator precedence should be a partial instead of a total order. The language was supposed to have user defined operators. The idea was that you would make some declarations that your new operator would bind e.g. "between * and +", or "tighter than *". The system would build up a minimal partial order that satisfied these constraints. One of nice things about such a system is its compositionality: If you mix and match custom operators from different modules, you wouldn't get a conflict or a random precedence order, instead, you'd simply be forced to disambiguate using parentheses. Contrast this with Haskell, which also has custom operators, but only a fixed number of precedence slots (10 IIRC), and some libraries really suffer from the fact that there's no "good one" available that works for the intended usage.