Re^8: Definition of numerically equal and rationale for 'you' == 'me'

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")
[download]

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".

Comment on Re^8: Definition of numerically equal and rationale for 'you' == 'me' Select or Download Code

Replies are listed 'Best First'.
Re^9: Definition of numerically equal and rationale for 'you' == 'me' by moritz (Cardinal) on Mar 03, 2012 at 13:32 UTC
Well, everything is possible with the right amount of disambiguation rules. Perl 6 doesn't have barewords, and type names must be predeclared. If a subroutine of name `x` and another symbol with that name (type name, constant, enum element) are in scope, the parser disambiguates in favor of the latter, unless there are parens after the token. In fact, constants can give you a taste of sigil-less Perl 6 already: `use v6; constant x = 4; say x x x # produces 4444` [download] This works today in both Rakudo and Niecza. Perl 6 - second systems done right	[reply] [d/l] [select]
Re^10: Definition of numerically equal and rationale for 'you' == 'me' by JavaFan (Canon) on Mar 03, 2012 at 14:14 UTC
That works in Perl 5 as well: `perl -Mconstant=x,1 -MO=Deparse -e 'print x x x' print '1' x '1'; -e syntax OK` [download] But: `perl -MO=Deparse -e 'sub x {1} print x x x' sub x { 1; } print x(x(x())); -e syntax OK` [download]	[reply] [d/l] [select]
Re^11: Definition of numerically equal and rationale for 'you' == 'me' by moritz (Cardinal) on Mar 03, 2012 at 14:53 UTC
Exactly. That's what I meant with my last paragraph in Re^7: Definition of numerically equal and rationale for 'you' == 'me'. Without sigils, you have to be much more careful, about whether a term or an infix is expected, and errors are more likely to go unnoticed. So possible, but in general a bad idea. Perl 6 - second systems done right	[reply]