== Quote from Steven Schveighoffer (schvei...@yahoo.com)'s article > Currently, D supports the special symbol $ to mean the end of a > container/range. > However, there is no analogous symbol to mean "beginning of a > container/range". For arrays, there is none necessary, 0 is always the > first element. But not all containers are arrays. > I'm running into a dilemma for dcollections, I have found a way to make > all containers support fast slicing (basically by imposing some > limitations), and I would like to support *both* beginning and end symbols. > Currently, you can slice something in dcollections via: > coll[coll.begin..coll.end]; > I could replace that end with $, but what can I replace coll.begin with? > 0 doesn't make sense for things like linked lists, maps, sets, basically > anything that's not an array. > One thing that's nice about opDollar is I can make it return coll.end, so > I control the type. With 0, I have no choice, I must take a uint, which > means I have to check to make sure it's always zero, and throw an > exception otherwise. > Would it make sense to have an equivalent symbol for the beginning of a > container/range? > In regex, ^ matches beginning of the line, $ matches end of the line -- > would there be any parsing ambiguity there? I know ^ is a binary op, and > $ means nothing anywhere else, so the two are not exactly equivalent. I'm > not very experienced on parsing ambiguities, but things like ~ can be > unambiguous as binary and unary ops, so maybe it is possible. > So how does this look: coll[^..$]; > Thoughts? other ideas? > -Steve
I like it, if only for its happy aesthetic properties.
