Just read S03: Changes to Perl operators. Impressive consistency improvements. I like the new x (string multiply) versus xx (list multiply) distinction.
I suppose the vast number of operators that Perl supports, compared to other languages, is made possible by sigils; that is, languages without sigils couldn't so easily use x or xx as an operator. BTW, I was surprised to learn that the string multiply operator is commutative in Python (that is, "X"*3 and 3*"X" both produce "XXX"), which looks a bit odd to me (you learn these things playing golf you see ;-).
I also revisited the lovingly crafted Periodic Table of the Operators -- which clarifies why Perl is sometimes referred to as an "operator-oriented language".
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I suppose the vast number of operators that Perl supports, compared to other languages, is made possible by sigils; that is, languages without sigils couldn't so easily use x or xx as an operator.
Technically that's not quite correct. The really interesting property that makes that possible is predictive parsing. That is, the Perl parsers always knows whether to expect an infix operator or something termish (a prefix operator or a term, like for example a number, variable, subroutine call etc.).
Even in an imaginary Perl without sigils, the following code could be parsed unambiguously:
# imaginary sigilless Perl
my x = 42;
say x x x;
The parser knows that say is a listop, and after that it expects a term. Thus the first x is term (here a variable), but since two terms in a row are forbidden, the next thing must be an infix operator (or maybe a semicolon to terminate the statement). Thus the second x is parsed as the repetition operator. And so on.
Predictive parsing is also what makes it possible to use the slash / both as an infix operator, and as a regex delimiter.
But even if it worked in theory, a sigil-less language with such a wealth of infix operators would probably be rather hard to read, and it would be much harder (if not impossible) to give good error messages in the case of syntax errors.
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Even in an imaginary Perl without sigils, the following code could be parsed unambiguously:
No, it cannot. Stepping away the additional problem with say (the first x can be seen as a filehandle), you're forgetting that sigils make barewords possible. You're x x x can be parsed in several ways:
$x x $x
x(x($x))
x::->x("x")
or some combination there off. That is, if we'd dropped sigils, a bare x can be a (scalar) variable, an operator, a class name, a subroutine, or the string "x". | [reply]
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