Hi All,
This is a fascinating answer I got back from Chat GPT:
-T
raku: I am going to be pushing (with push) various variables
unto an array: strings, integers, classes, etc.. Is there
a way to ask a cell in the array what type of data is in them?
Yes. In Raku, every object knows its type.
The most direct way is to use the .WHAT method:
my @a;
@a.push("hello");
@a.push(42);
@a.push(3.14);
class Person { }
@a.push(Person.new);
for @a -> $item {
say $item.WHAT;
}
Output:
(Str)
(Int)
(Rat)
(Person)
If you want just the type name without the surrounding parentheses:
say $item.^name;
Output:
Str
Int
Rat
Person
Testing for a specific type
Usually, instead of asking what the type is, you ask whether it is a
given type using ~~ (smartmatch):
given $item {
when Str { say "It's a string" }
when Int { say "It's an integer" }
when Person { say "It's a Person" }
default { say "Something else: {$item.^name}" }
}
or
if $item ~~ Int {
say "Integer";
}
elsif $item ~~ Str {
say "String";
}
Checking the exact type
If you need to know the exact type (not a subclass), you can compare .WHAT:
if $item.WHAT === Int {
say "Exactly an Int";
}
Example with a mixed array
class Dog { }
my @things = (
"abc",
123,
4.56,
Dog.new
);
for @things -> $x {
say "{$x.perl} is a {$x.^name}";
}
Output:
"abc" is a Str
123 is a Int
4.56 is a Rat
Dog.new is a Dog
In idiomatic Raku, ~~ is generally preferred when you're
making decisions based on type, while .^name or .WHAT are
more useful for introspection or debugging.
