(This time to the list)
> On 18 Mar 2017, at 10:19, ToddAndMargo <[email protected]> wrote:
> Request for Enhancement:
>
> Would you consider throwing a compiler error on the following:
>
> perl6 -e 'my $x=2;my $y=3; if $x = $y {say "yes";} else {say "no";}’
> yes
FWIW, I don’t think that will ever become a compile time error, but a warning
may be in place. Even although in Perl *5* this has been discussed at length
and considered to be a feature rather than a bug or a trap.
> It should have two == signs if it is followed by a {do something}
>
> This is the correct way:
>
> $ perl6 -e 'my $x=2;my $y=3; if $x == $y {say "yes";} else {say "no";}'
In Perl 5 many people use the syntax to assign the value of a complicated
expression to be useable inside the if statement:
if (my $x = frobnicate(42)) {
say $x
}
In Perl 6, we have a different syntax for that, by using a pointy block:
if frobnicate(42) -> $x {
say $x
}
Generally, in Perl 5 and Perl 6, when comparing against a constant, you could
consider teaching yourself to always put the constant on the left-hand side:
if 42 == $x
Should you then make a mistake, it will at least be obvious at runtime:
$ 6 'my $x = 42; say "same" if 42 = $x'
Cannot modify an immutable Int
One could argue this should be spotted at compile time.
HTH,
Liz
