diff options
Diffstat (limited to 'perl6.html.markdown')
| -rw-r--r-- | perl6.html.markdown | 58 |
1 files changed, 57 insertions, 1 deletions
diff --git a/perl6.html.markdown b/perl6.html.markdown index f86c3d64..fb052590 100644 --- a/perl6.html.markdown +++ b/perl6.html.markdown @@ -38,7 +38,7 @@ my $weird'variable-name_ = 5; my @array = 1, 2, 3; my @array = 'a', 'b', 'c'; # equivalent to : -my @array = <a b c>; # similar to perl5's qw, or Ruby's %w +my @array = <a b c>; # array of string, delimited by space. similar to perl5's qw, or Ruby's %w say @array[2]; # Arrays are 0-indexed @@ -57,6 +57,12 @@ say %hash<key2>; # if it's a string, you can actually use <> ## - Subs (subroutines, or functions in most other languages). Stored in variable, they use `&` sub say-hello { say "Hello, world" } +sub say-hello-to(Str $name) { # you can provide the type of an argument + # and it'll be checked at compile-time + + say "Hello, $name !"; +} + # since you can omit parenthesis to call a function with no arguments, you need to use `&` also to capture `say-hello` my &s = &say-hello; my &other-s = sub { say "anonymous function !" } @@ -64,6 +70,25 @@ my &other-s = sub { say "anonymous function !" } # `->`, lambda with arguments, and string interpolation my &lambda = -> $argument { "The argument passed to this lambda is $argument" } +### Containers +# In Perl 6, values are actually stored in "containers". +# the assignment operator asks the container on the left to store the value on its right +# When passed around, containers are marked as immutable. Which means that, in a function, +# you'll get an error if you try to mutate one of your argument. +# If you really need to, you can ask for a mutable container using `is rw` : +sub mutate($n is rw) { + $n++; + say "\$n is now $n !"; +} + +# If what you want is a copy instead, use `is copy`. + +# A sub itself returns a container, which means it can be marked as rw : +my $x = 42; +sub mod() is rw { $x } +mod() = 52; # in this case, the parentheses are mandatory +say $x; #=> 52 + ### Control Flow Structures # You don't need to put parenthesis around the condition, but that also means you always have to use brackets (`{ }`) for their body : @@ -180,6 +205,37 @@ $arg ~~ &bool-returning-function; # true if the function, passed `$arg` as an ar $a && $b && $c; # returns the first argument that evaluates to False, or the last argument $a || $b; +# Perl 6 has a quite comprehensive class system +## You declare a class with the keyword `class`, fields with `has`, methods with `method` +## `$.` declares a public field, `$!` declares a private field +## (a public field also has `$!`, which is its private interface) + +class A { + has $.field; + has Int $!private-field = 10; + + method get-value { + $.field + $!private-field + $n; + } + + method set-value($n) { + # $.field = $n; # This fails, because a public field is actually an immutable container + # (even from inside the class) + # You either need to use `is rw` on the `has` + # (which will make it mutable, even from outside the class) + # or you need to use the `$!` version : + + $!field = $n; # This works, because `$!` is always mutable + } +}; + +# Create a new instance of A with $.field set to 5 : +# note : you can't set private-field from here (more later on) +my $a = A.new(field => 5); +$a.get-value; #=> 18 +#$a.field = 5; # This fails, because the `has $.field` is lacking the `is rw` + + # More operators thingies ! ## Everybody loves operators ! Let's get more of them |