CoCoA » CoCoA-5

I think += is a big step over incr. After all how often we have for loops with step different from one?
I agree it would be nice, but just for a small elite.

We could also have the ++ operator but cannot have -- because that is used to mark end-of-line comments. In my opinion/experience, incrementing is a far more common operation than decrementing. However, a C++ programmer who wants to use CoCoA would probably be surprised if ++ works but -- does not.

Here are four potential code samples:

*(A)* ++counter;
*(B)* counter += 1;
*(C)* incr counter;
*(D)* incr(ref counter);
*(E)* counter := counter+1;

One big advantage of rejecting the idea of introducing += and friends is that there would be no need to fiddle around inside the interpreter... to my mind the code is not as self-documenting at the original author believes :-/

Earlier comments have effectively voted against (A) and (C); we already have (D) and (E). So the only point to resolve is (B). Christof was in favour (comment 2), Anna was against (comment 6).

The advantage of += and friends is that they are well-appreciated by C/C++ programmers.

A disadvantage is that people who do not know C/C++ might find them cryptic. Another point is that in CoCoA-5 they would probably not be especially efficient -- somehow in C++ they "feel like" they ought to be particularly efficient. Anyway, the aim of CoCoA-5 is not to be especially efficient (but also not to be needlessly inefficient).

It seems reasonable to assume that A += B; would mean exactly the same as A := A+B (with the exception that A is evaluated only once). This could lead to some mildly surprising uses: let R be a ring and I and ideal in R, then R /= I would mean R := R/I. Of course, no one is compelled to write such a command.

NOTE in the CoCoA-5 packages incr is used in about 35 places (currently). Not sure if I can find out how often we use something like A := A + B;