Ada-Style Range Types with Value Range Propagation in Arithmetic

"Nordlöw" per.nordlow at gmail.com
Wed Mar 19 14:04:51 PDT 2014


I'm trying to extend my wrapper class Bound to support CTFE Value 
Range Propagation in primary in opUnary and opBinary similar to 
what Ada's Range Types.

My current try so far for binary arithmetic is

     auto opBinary(string op, U,
                   U lower_rhs = U.min,
                   U upper_rhs = U.max,
                   string file = __FILE__,
                   int line = __LINE__)(Bound!(U, lower_rhs, 
upper_rhs) rhs)
     {
         Bound!(CommonType!(T, U),
                min(T.min, U.min),
                max(T.max + U.max)) tmp = void; // TODO: Needs fix
         mixin("tmp = _value " ~ op ~ "rhs;");
         mixin(check());
         return tmp;
     }

but this errors as

bound.d(120,19): Error: undefined identifier U and I don't 
understand why I can't parameterize opBinary in this way.

Ideas anyone?

For reference, this older version

https://github.com/nordlow/justd/blob/master/bound.d

compiles but do not do value range propagation in arithmetic.


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