🚀 go-pugleaf

In <DJAJ44.J5w@research.att.com>, ark@research.att.com (Andrew Koenig) writes:

>How would you arrange for the expression 3<4 to yield the right type?

   type unsigned char bool;

   inline bool operator<(int x, int y) {
      return bool(x < y); }

would probably do the trick.  Just because the definition of bool
is opaque for the purposes of typing, there shouldn't be any
problem casting a value to an opaque type because the compiler
could cast to the underlying type.  The only difference I see in
an opaque "type" vs transparent "typedef" is when matching
types.

Since I can overload on bool as defined above, I can define a
global operator (when necessary) to solve problems like this.
It should also be possible to solve the problem by...

   inline operator bool(int x) {return (bool)(unsigned char)x;}

Although this approach might be enhanced by something more
like...

   inline implicit operator bool(int x) {return (bool)(unsigned char)x;}

where the "implicit" keyword would put a user-defined type
conversion at the same level as that of the built-in type conversions.
Right now, when the user defines a type conversion it is really
a second class citizen compared to the "trivial" conversions and
the built-in conversions because of the rule that says only one
conversion can be applied.

Michael Lee Finney



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