Welcome to Day 5 of this lovely Perl 6 One-Liner Advent Calendar! Today, we’ll answer the question of what’s the date today (and tomorrow we can talk about palindromes if you want). So, to print the answer, you can use the following line of Perl 6 code: DateTime.now.yyyy-mm-dd.say It looks transparent and prints the date … Continue reading “🎄 5/25. What’s the date today in Perl 6?”
Category: Raku
🎄 4/25. Working with big numbers in Perl 6
Welcome to Day 4 of the Perl 6 One-Liner Advent Calendar! Today, we’ll look at the Problem 13 of Project Euler. Let me show a screenshot of it: Indeed, it looks huge, and the task is to find the first ten digits of the sum of a hundred integers, each consisting of 50 digits. Sounds … Continue reading “🎄 4/25. Working with big numbers in Perl 6”
🎄 3/25. Generating random integers in Perl 6
Welcome to Day 3 of the Perl 6 One-Liner Advent Calendar! Today, we will generate random numbers. You may ask, what’s the deal with it, isn’t it a routine task to call a kind of a rand function? Well, in some sense, yes, but in Perl 6, you might prefer calling a method. Let’s look at the … Continue reading “🎄 3/25. Generating random integers in Perl 6”
🎄 2/25. Grepping dividable numbers in Perl 6
Welcome to Day 2 of the Perl 6 One-Liner Advent Calendar! Today, we’ll solve a nice task from Project Euler with number 1. Once again, let me warn you that the rest of the text contains a solution, so you are welcome to make a pause to think of your own solution first. But I am … Continue reading “🎄 2/25. Grepping dividable numbers in Perl 6”
🎄 1/25. Generating random passwords in Perl 6
Welcome to the first day of the brand new Perl6.Online Advent Calendar! This year, its theme is Perl 6 One-Liners (a pun from perl6.onliners). Thus, welcome to this year’s Perl 6 One-Liner Advent Calendar. The whole perl6.online blog was initially planned to be daily, so it’s a great opportunity to keep the pace for at least another … Continue reading “🎄 1/25. Generating random passwords in Perl 6”
📺 Perl 6 grammars to create a simple interpreter
Here’s a screencast from a lightning talk that I gave at ‘Perl & Friends’ event in Barcelona today. That’s a simplified version of the previous talk 🙂
🎁 Christmas sale!
Only until the end of the year, you can buy the Perl 6 Calendar 2019 and Using Perl 6 book as a pack!
📺 Creating a compiler with Perl 6
A screencast recorded during a talk at the Amsterdam Perl mongers meeting on 6 November 2018.
📘 Variables in Perl 6: Introspection
Due to the mechanism of introspection, it is easily possible to tell the type of the data living in a variable (a variable in Perl 6 is often referred as a container). To do that, call the predefined WHAT method on a variable. Even if it is a bare scalar, Perl 6 treats it internally … Continue reading “📘 Variables in Perl 6: Introspection”
📘 Int type in Perl 6
The Int type is intended to host integer variables of arbitrary size. For example, no digit is lost in the following assignment: my Int $x = 12389147319583948275874801735817503285431532; say $x; A special syntax exists for defining integers with an other-than-10 base: say :16<D0CF11E0> Also, it is allowable to use the underscore character to separate digits … Continue reading “📘 Int type in Perl 6”
📘 Prefix operators ! and not in Perl 6
Prefix operators are those that come in front of their operands. Obviously, prefix operators require only one operand. In some cases, the symbol of the operation can be used as an infix operator when it stands between two operands. ! is the Boolean negation operator. say !True; # False say !(1 == 2); # True … Continue reading “📘 Prefix operators ! and not in Perl 6”
📘 Frequently used special variables in Perl 6
The $_ variable is the one similar to that in Perl 5, which is the default variable containing the current context argument in some cases. Like any other variable, the $_ is an object in Perl 6, even in the simplest use cases. For example, the recent example .say for @*ARGS implicitly contains the $_.say … Continue reading “📘 Frequently used special variables in Perl 6”
📘 Hello, World! in Perl 6
The Perl 6 compiler can either read a programme from a file or from the content of the -e command line switch. The simplest “Hello, World!” programme looks like this: say “Hello, Perl 6!”; Save it in a file and run: $ perl6 hello.pl Hello, Perl 6! Alternatively, you may use the -e option: $ … Continue reading “📘 Hello, World! in Perl 6”
📘 Array in Perl 6
The Array variables (i.e., all the variables starting with the @ sigil) are equipped with a couple of simple but rather useful methods. my @a = 1, 2, 3, 5, 7, 11; say @a.Int; # array length say @a.Str; # space-separated values If you print an array, you get its value as a space-separated list … Continue reading “📘 Array in Perl 6”
📘 Prefix operators ? and so in Perl 6
? is a unary operator casting the context to a Boolean one by calling the Bool method on an object. say ?42; # True The second form, so, is a unary operator with lower precedence. say so 42; # True say so True; # True say so 0.0; # False
📘 Prefix operator temp in Perl 6
temp creates a temporary variable and restores its value at the end of the scope (like it does the local built-in operator in Perl 5). my $x = ‘x’; { temp $x = ‘y’; say $x; # y } say $x; # x Compare it with the following operator, let.
📘 Built-in types in Perl 6
Perl 6 allows using typed variables. To tell the compiler that the variable is typed, you simply need to name the type while declaring the variable. Some of the types available in Perl 6 are obvious and do not need comments: Bool, Int, Str Array, Hash, Complex Some might require a small comment: Num, Pair, … Continue reading “📘 Built-in types in Perl 6”
📘 Variables in Perl 6: Twigils
In Perl 6, a variable name may be preceded by either a single-character sigil, such as $, @ or %, or with a double character sequence. In the latter case, this is called a twigil. The first character of it means the same thing that a bare sigil does, while the second one extends the … Continue reading “📘 Variables in Perl 6: Twigils”
📘 Variables in Perl 6: Sigils
Perl 6 uses sigils to mark variables. The sigils are partially compatible with the Perl 5 syntax. For instance, scalars, lists and hashes use, respectively, the $, @, and % sigils. my $scalar = 42; say $scalar; It’s not a surprise that the code prints 42. Consider the following fragment, which also gives a predictable … Continue reading “📘 Variables in Perl 6: Sigils”
📘 Bool in Perl 6
The usage of the Bool variables is straightforward although there are some details about which you might want to know. The Bool type is a built-in enumeration and provides two values: True and False (or, in a full form, Bool::True and Bool::False). It is permissible to increment or decrement the Boolean variables: my $b = … Continue reading “📘 Bool in Perl 6”