Implement ++ and -- operators in the Millfork language about millfork HOT 4 CLOSED

As I just learned, the behavior that I described can be achieved by
i += 1 and i -=1
This gets compiled to inc and dec

I, nevertheless, think that implementing i++ and i-- would also help developers, since, coming from the C++, C# and Java world, the i++ first came into my mind. Also the += and -= operators are mainly used for more complex expressions I think.

from millfork.

Sorry, Millfork will never have those operators. Millfork explicitly rejects bad parts of syntax of B (I guess it's cool that you can take code from late 60s and compile it as C#, but Millfork is not for that), and these operators are only the tip of the iceberg. In fact, the only reason B had ++ and -- was because the compiler was too dumb to optimize +=1 and -=1, and that incapability trickled down to too many modern languages. Millfork is an optimizing compiler, and +=1 and -=1 are explicitly special-cased to compile to a single INC/DEC when possible.

There are several reasons for not including ++ and --:

1. Millfork does not have unary operators other than -. This is by design, and even - was only added later.
2. ++ and -- introduce parsing ambiguity. --a currently means -(-a) and introducing a new -- operator would break that. Similarly with things like a--b, which is currently parsed as a-(-b)
3. Most languages that have those operators, treat them as expressions, which can cause confusion between preincrement and postincrement variants as @agg23 mentioned in the previous comment. In Millfork, assignments are not expressions, and since they are not, += 1 is fine and readable.
4. Most instances of ++ are found in C-style loops, but Millfork has range-based loops.
5. Some languages use ++ and -- for other things.

Further reading:

• list of some more important differences between Millfork and C: https://github.com/KarolS/millfork/blob/master/docs/various/cdiff.md
• this article was hugely influential on Millfork's syntax: https://eev.ee/blog/2016/12/01/lets-stop-copying-c/
• why Swift removed those operators: https://github.com/apple/swift-evolution/blob/master/proposals/0004-remove-pre-post-inc-decrement.md
• why Ruby doesn't have them: http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-talk/2710
• why Rust doesn't have them: https://github.com/dtolnay/rust-faq#why-doesnt-rust-have-increment-and-decrement-operators

from millfork.

I would argue that += is much clearer than ++ due to the expression nature of x++. You could do something like y = x++ or y = ++x and get different results, and often developers don't properly understand what the expression means.

from millfork.

Thanks, makes 100% sense to me :-)

from millfork.