On Jul 12, Vincent said:
>I'm reading the chapter on Subroutines in the camel book and have a question
>about the prototypes described on page 226.
>At first my understanding was, there should be a $ or @ for each parameter
>expected. Or a \@ or \$ for each reference expected. But one of the
>examples reads:
A \@ means that the function is expecting an array, and it will convert it
into a reference to an array. A \$ means that the function is expected an
EXPLICIT scalar variable, and will turn it into a reference. A $ means
that the argument will be evaluated in scalar context.
sub FOO ($) { print $_[0] }
@a = (10,20,30);
$b = 30;
FOO(@a); # 3 -> scalar(@a) == 3
FOO($b); # 30
FOO(@a,$b); # compile-time error -- too many args
>Also there's some prototypes with a semicolon in them
The semicolon indicates that the following arguments are optional.
Prototypes are documented in 'perlsub', and I have an article that
discusses them:
http://www.pobox.com/~japhy/articles/pm/2000-03.html
"Typeglobs and Prototypes"
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