First class lazy Interval

[Michel Fortin]

On 2009-02-27 23:02:30 -0500, Daniel Keep <daniel.keep.lists at gmail.com> said:

> On the whole, I think the use cases for this sort of syntax are just far
> too few and specialised to warrant syntax for them, especially when the
> syntax proposed is very restrictive.
> 
> Especially when you can do it in a library without too much effort.
> Hell, my first instinct was to alias inter to Z to make it even shorter.
>  Then it's only 3 characters more than native syntax, and more flexible.

But what I'm proposing is that a..b just become a shortcut for 
inter[a..b], or whatever is the standard interval struct in the 
standard library. Isn't that exactly what you're trying to do (a 
shortcut) by shortening inter[a..b] to Z[a..b] ?

> Using ... to indicate an inclusive range doesn't solve the problem.  How
> do you do (a,b]?  Introduce yet another operator?  What about (a, b)?

Perhaps using "..." was a bit too much to ask. But there is no reason 
why the standard library interval cannot support all kinds of bounds 
just like inter does. The syntax just won't be as nice as a..b.

Basically, all the compiler would do is map a..b to inter[a..b] and 
leave everything else to the standard library. So it's not removing any 
option, it just consistently allow you to write a..b whatever the place.

-- 
Michel Fortin
michel.fortin at michelf.com
http://michelf.com/