Roedy Green wrote: > On Sun, 30 Sep 2007 10:47:13 -0000, Summercool > <[EMAIL PROTECTED]> wrote, quoted or indirectly quoted someone > who said : >> and now n will be 3. I think C++ and PHP can let you do that, using >> their reference (alias) mechanism. And C, Python, and Ruby probably >> won't let you do that. What about Java and Perl?
> Seem to me you could in FORTRAN and Pascal, and maybe even Algol. FORTRAN generally looked like call by reference, but was often actually implemented element variables as copy-in at call time and copy-out at return time. In standard older FORTRAN, the effective results were the same. I don't know how things stand with modern Fortran, where some new features have made the assumption that copy-in-copy-out is equivalent to reference more dangerous. Ada is /defined/ as using copy-in-copy-out for element variables. ALGOL had a weird "by name" convention. The semantics were essentially that, for each argument, a closure (historically called a "thunk") was constructed, and every time the parameter was referenced, the corresponding closure was called. Theoretically elegant, but hideous to implement, and with bizarre side-effects in certain cases. -- John W. Kennedy Read the remains of Shakespeare's lost play, now annotated! http://pws.prserv.net/jwkennedy/Double%20Falshood/index.html -- http://mail.python.org/mailman/listinfo/python-list
