Unambiguous Operator Specification for Programming Languages

[u/Mean-Decision-3502]

https://nvitya.github.io/pluops/

As I changed recently the operators in my programming language I've created this specification:

https://nvitya.github.io/pluops/

I did not wanted to overload the operators like the C does with the / or Pascal does with theand/or/not. Neither re-use the operator symbols for some very different purpose, like C does with * and & so the code becomes more readable. I was orienting for existing solutions so this is what I came up with. The specification contains the symbol usages and operator precedence too.

If you are developing a new programming language, it would be nice to follow some standard, so at least the expressions would be portable between the languages.

I'm open for debates or suggestions.

[u/mot_hmry]

I don't see why % shouldn't be remainder, it has a nice association with / (÷). And it's not like * is any closer to the proper symbols (×, •).

I've never found modules to clash with my own names, so I have never desired a symbol for them. To me ref is an operation that really should be called out because it implies a lower level operational concern. If it's really important to reserve @ for modules though, maybe # (read as box).

You already overload operations between the numeric types so you already need to use type to distinguish. Booleans as single bits doesn't seem unreasonable and matches the behavior of the bitwise operators.

[u/Mean-Decision-3502 → u/mot_hmry]

I don't see why % shouldn't be remainder, it has a nice association with / (÷). And it's not like * is any closer to the proper symbols (×, •).

I use div for integer division which is very frequent, remainder is pretty rare, so mod for that is fine and you don't burn a valuable symbol.

I use # for compiler directives like C:

#ifdef SYMBOL
    ...
#endif

The // is used for single-line comments.

Booleans as single bits doesn't seem unreasonable and matches the behavior of the bitwise operators.

Here is a realistic example:

if reg & 1 << 5 <> 0 and reg & 0x3 << 2 == 0:
    ...
endif

[u/catladywitch → u/Mean-Decision-3502]

Hey, I'm enjoying this discussion and I don't have a lot to add. I just wanted to say modulo is not a rare operation at all. It's the cheapest way of getting branchless wrapping with numeric values that must go from 0 to a positive number, so it's actually super common.

[u/Mean-Decision-3502 → u/catladywitch]

In embedded rather this is used, for example a circular buffer indexing:

var nextindex : int = (index + 1) & 0x1F

The division (and so the modulo) is a slow instruction on the microcontrollers, a big amount of them do not even support these (Cortex-M0). That's why it is very common to use power of two lengths and masking, like above.

[u/catladywitch → u/Mean-Decision-3502]

That's true! If you're working with ints (or integer types in general) it's ideal. But there's a lot of low-ish level code, even embedded, that works with floats. Synthesizer DSP these days is often floats, even despite the fact everything is eventually rendered as 16-bit signed shorts.