String comparison
Raku uses strong typing dynamically (and gradual typing statically), but normal string and numeric comparisons are coercive. (You may use generic comparison operators if you want polymorphic comparison—but usually you don't. :)
String comparisons never do case folding because that's a very complicated subject in the modern world of Unicode. (You can explicitly apply an appropriate case-folding function to the arguments before doing the comparison, or for "equality" testing you can do matching with a case-insensitive regex, assuming Unicode's language-neutral case-folding rules are okay.)
sub compare($a,$b) {
my $A = "{$a.WHAT.^name} '$a'";
my $B = "{$b.WHAT.^name} '$b'";
if $a eq $b { say "$A and $B are lexically equal" }
if $a ne $b { say "$A and $B are not lexically equal" }
if $a gt $b { say "$A is lexically after $B" }
if $a lt $b { say "$A is lexically before than $B" }
if $a ge $b { say "$A is not lexically before $B" }
if $a le $b { say "$A is not lexically after $B" }
if $a === $b { say "$A and $B are identical objects" }
if $a !=== $b { say "$A and $B are not identical objects" }
if $a eqv $b { say "$A and $B are generically equal" }
if $a !eqv $b { say "$A and $B are not generically equal" }
if $a before $b { say "$A is generically after $B" }
if $a after $b { say "$A is generically before $B" }
if $a !after $b { say "$A is not generically before $B" }
if $a !before $b { say "$A is not generically after $B" }
say "The lexical relationship of $A and $B is { $a leg $b }" if $a ~~ Stringy;
say "The generic relationship of $A and $B is { $a cmp $b }";
say "The numeric relationship of $A and $B is { $a <=> $b }" if $a ~~ Numeric;
say '';
}
compare 'YUP', 'YUP';
compare 'BALL', 'BELL';
compare 24, 123;
compare 5.1, 5;
compare 5.1e0, 5 + 1/10;Output:
Unicode normalization by default
Be aware that Raku applies normalization (Unicode NFC form (Normalization Form Canonical)) by default to all input and output except for file names See docs. Raku follows the Unicode spec. Raku follows all of the Unicode spec, including parts that some people don't like. There are some graphemes for which the Unicode consortium has specified that the NFC form is a different (though usually visually identical) grapheme. Referred to in Unicode standard annex #15 as Canonical Equivalence. Raku adheres to that spec.
One that people seem to get hung up on is the Kelvin symbol "K" getting automatically converted to ASCII uppercase "K".
In most programming language the previous two objects wouldn't be equivalent, but since Raku follows the Unicode specification, and normalization is applied automatically, they show up as equivalent.
It's officially identified as a possible trap for string handling. See docs.
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