Ranges

[cpurdy]

Swift uses .. for ranges. Not surprising.

I just learned that they use ..< exclusive ranges. Ecstasy uses the math notation, e.g. [inclusive..exclusive), which causes all sorts of IDE and editor confusion.

Curious if anyone has an opinion on this topic?

[ggleyzer]

I like it; while (a..b] still looks to me a bit better than a..<b, the fact that you can do a>..b and a>..<b and keep the parenthesis balanced is a big plus. And then some expressions do look like emoticons, for example:

(-w)>..<(w)
(o)>..<(O)

[cpurdy]

Plan of record:

• Get rid of the [x..y] and [x..y) constructs e.g.

    for (Int i : 5..10)     // this will still exist 
    for (Int i : [5..10])   // this used to be the same behavior as line above, but this goes away
    for (Int i : [5..10))   // this is exclusive on the upper bound (10), but this goes away

• The old way could not do exclusive lower + exclusive upper bound:

    x === (x)         // basic expression guarantee
    a..b === (a..b)   // this follows the above rule, but the parenthesis implied "exclusive mode"

• Decision: adopt the "Swift like" operator style, aka "gremlin operators" (Mark Falco's name for them)

    a  ..  b
    a >..  b
    a  ..< b
    a >..< b

[cpurdy]

OK, this one is all done and in. The old syntax has also been removed.

(The bootstrapped lexer / parser built in Ecstasy still needs to be updated similarly.)