On Dec 9, 09 17:25, Simen kjaeraas wrote:
On Wed, 09 Dec 2009 09:36:56 +0100, Don <[email protected]> wrote:CHANGES BASED ON FURTHER COMMENTS -------------------- x ^^ y is right associative, and has a precedence intermediate between unary and postfix operators. The type of x ^^ y is the same as the type of x * y. * If either x or y are floating-point, the result is pow(x, y). If both x and y are integers, the following rules apply: * If x is the compile-time constant 0, x^^y is rewritten as (y==0)? 1 : 0 * If x is the compile-time constant 1, x^^y is rewritten as (y,1) * If x is the compile-time constant -1 and y is an integer, x^^y is rewritten as (y & 1) ? -1 : 1. * If y == 0, x ^^ y is 1. * If y > 0, x ^^ y is functionally equivalent to { auto u = x; foreach(i; 1..y) { u *= x; } return u; } * If y < 0, an integer divide error occurs, regardless of the value of x. ----------- Note that by definining the 0,1, -1 cases as "rewriting" rules rather than return values, it should be clearer that they don't apply to variables having those values. I think this covers everything useful, while avoiding nasty surprises like double y = x ^^ -1; // looks like reciprocal, but isn't! // Yes, this IS the same problem you get with double y = 1/x. // But that's doesn't make it acceptable. I have a possible solution to that one, too. I don't think we can afford to spend much more time on this. Is everyone happy now?Might I enquire as to why the exponent should be allowed to be signed for integer exponentiation? It's been covered several times - it makes no sense. Apart from that - great job!
Because 3^^-1 would become 3^^4294967295 (note: int can be implicitly converted to uint) which then you spend 17 seconds to get 2863311531 and wonder what's going on.
