KennyTM~ wrote:
On Dec 1, 09 22:30, Steven Schveighoffer wrote:
An idea I just had when thinking about how ugly opDispatch and opBinary
operators will be if we get those was, wouldn't it be cool if the
compiler could translate:
myTemplateMethod("abc" || "def")() if(condition) {}
to
myTemplateMethod(string __x)() if((__x == "abc" || __x == "def") &&
condition) {}
It makes dispatch based on compile-time strings much more palatable, for
example:
opDispatch("foo" || "bar")() {...}
opBinary("+" || "-" || "*")(int rhs) {...}
instead of:
opDispatch(string fn)() if(fn == "foo" || fn == "bar") {...}
opBinary(string op)() if(op == "+" || op == "-" || op == "*")(int rhs)
{...}
In fact, it can be generalized to any type which has literals:
factorial(int x)(){ return factorial!(x-1)() * x;}
factorial(1)() { return 1;}
What I don't know is if the || works in all cases -- because something
like true || false is a valid expression. Maybe someone can come up with
a better way.
-Steve
Alternative suggestion:
Make "x in y" returns a bool and works for arrays. Then you can write
int opBinary(string s)(int rhs) if (s in ["+", "-", "*", "/", "^", "|",
"&"]) { ... }
It's a bit difficult to see a very thin operator mask a linear
operation, but I'm thinking maybe "x in y" could be defined if y is a
compile-time array. In that case, the compiler knows the operation and
the operand so it may decide to change representation as it finds fit.
Andrei
