🚀 go-pugleaf

In article <46vaga$dng@marina.cinenet.net>, scotty@cinenet.net (J Scott
Peter XXXIII I/III) writes:
|> a += b	=>  a = a + b
|> a + b	=>  tmp = a; a + b; tmp
|> Similarly for other composite operators.
|> 
|> a != b	=> !(a == b)	and vice versa
|> a >= b	=> !(a < b)	etc
|> a < b	=> a - b < 0	etc
|> a - b	=> a + (-b)	and vice versa
|> -b		=> 0 - b
|> +b		=> b
|> a++		=> a += 1	also --
|> a->b		=>  (*a).b

The standard header <utility> (20.2.1) already defines template-
operators for the relational operators, deducing them to == and <
a != b		=> !(a == b)
a >  b		=>   b < a
a <= b		=> !(b < a)
a >= b		=> !(a < b)

You can extend this idea:

template<class T> T& operator+=(T&a, T&b) { return a = a + b; }
template<class T> T  operator- (T&a, T&b) { return a + (-b); }
template<class T> T  operator- (T&a)      { return 0 - a; }
template<class T> T& operator+ (T&a)      { return a; }
template<class T> T& operator++(T&a)      { return a += 1; }
template<class T> T& operator++(T&a,int)  { return ++a; }

But unfortunately you can't do it this way for -> as it must be
a nonstatic memberfct (13.5.6 [over.ref]).


Ulf Schuenemann

--------------------------------------------------------------------
 ,_.   Ulf Schuenemann
#,  \  Fakultaet fuer Informatik, Technische Universitaet Muenchen, Germany.
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