Andrej Mitrovic:
> Honestly, I think this would just encourage writing sloppy code.
I don't believe this, on the other hand I believe the current behaviour is
bug-prone.
> Using min(x, $) explicitly informs the reader of the code of exactly
> what happens.
Right. The problem is that in some cases you may forget to add that min(x, $).
> It's harder to tell when it's implicit.
Slicing syntax is used all the time in both Python and D code, so the Python
and D programmers learn quickly and keep in mind what it does. Implicit
behaviours are a problem when they are uncommon things, or library functions,
etc, much less when they are built-in safety nets you use every five lines of
code :-)
Not only that,
> but it can introduce bugs in your code - because while you might use
> any upper bound, you're still not allowed to index beyond the length
> of the array.
Writing hundreds of thousands of lines of Python code I've seen that the
saturating semantics we are talking about is not bug-prone (in fact it avoids
some bugs).
> Imagine this could was accepted by DMD:
>
> void main()
> {
> auto userArgs = ["foo"]; // runtime arguments by some user input
>
> auto firstTwo = userArgs[0..2]; // accepted by the new language change,
> // implicitly
> changes 2 to min(2, $)
>
> // more code here
>
> firstTwo[1] = "test"; // oops!
> }
Programmers just quickly learn that indexes and slices have a bit different
semantics.
Bye,
bearophile
