Re: [stack] Re: Barebone implementation of concatenative language in c or c++

William Tanksley, Jr scripsit:

> No; C++ allows call by reference semantics (explicitly specified, of
> course) without being lazy at all. An early Fortran had implicit call
> by reference, again not lazy (but, I'm told, very dangerous). I don't
> use Perl, but I'm told it's call-by-reference.

The default calling strategy for Fortran is and always has been call by
reference.  The dangerous bit was an implementation, not a specification,
error.  Buggy compilers conflated all instances of identical constants
(thus there would be only one cell containing 5 no matter how many literal
5s there were in the code) without realizing that literals passed as
arguments could not be conflated in such a manner.

Perl is technically call-by-reference, but it is usual to provide lexically
scoped variables that are mapped to the values of the call-by-reference
parameters, and to assign them first thing in each procedure.  The main
exception is the comparison procedure passed to "sort", which uses
by-reference arguments directly (always named "$a" and "$b") for speed.

-- 
John Cowan  [email protected]   http://ccil.org/~cowan
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