🔬 75. my $x = $x in Perl 6

What happens if you’ll try to create a new variable and immediately initialise it by itself, as shown in the following test code: my $x = $x; This does not work (which is expected), but Perl 6 is so kind to the user  that it gives an error message prepared especially for this case: ===SORRY!=== … Continue reading “🔬 75. my $x = $x in Perl 6”

🔬73. Keys, values, etc. of hashes in Perl 6

Today, we will take a look at a few methods of the Hash class that return all hash keys or values or both: > my %h = H => ‘Hydrogen’, He => ‘Helium’, Li => ‘Lithium’; {H => Hydrogen, He => Helium, Li => Lithium} > %h.keys; (H Li He) > %h.values; (Hydrogen Lithium Helium) … Continue reading “🔬73. Keys, values, etc. of hashes in Perl 6”

🔬72. Superscripts in Perl 6

In Perl 6, you can use superscript indices to calculate powers of numbers, for example: > 2⁵ 32 > 7³ 343 It also works with more than one digit in the superscript: > 10¹² 1000000000000 You can guess that the above cases are equivalent to the following: > 2**5 32 > 7**3 343 > 10**12 … Continue reading “🔬72. Superscripts in Perl 6”

🔬71. Implementing Int.sleep() in Perl 6

Hello! Yesterday, I was giving my Perl 6 Intro course at the German Perl Workshop in Gummersbash. It was a great pleasure to prepare and run this one-day course, and, while it was difficult to cover everything, we touched all main aspects of the Perl 6 language: from variables to regexes and parallel computing. Of … Continue reading “🔬71. Implementing Int.sleep() in Perl 6”

🔬70. Examining the enum type in Perl 6

In Perl 6, you can create enumerations like this: enum colour <red orange yellow green blue violet>; Having this said, you can use the new name as a type name and create variables of that type: my colour $c; $c = green; say $c; # green say $c.Int; # 3 As you would rightly expect, … Continue reading “🔬70. Examining the enum type in Perl 6”

🔬68. The smartness of the sequence operator in Perl 6, part 1

In Perl 6, you can ask the sequence operator to build a desired sequence for you. It can be arithmetic or geometric progression. All you need is to show the beginning of the sequence to Perl, for example: .say for 3, 5 … 11; This prints numbers 3, 5, 7, 9, and 11. Or: .say … Continue reading “🔬68. The smartness of the sequence operator in Perl 6, part 1”

🔬67. Redeclaration of a symbol in Perl 6

Today, we will see how Perl 6 helps to keep our programs better. Redeclaration of a variable Examine the following program: my $x = 1; my $x = 2; say $x; You can immediately see that this program is not entirely correct. Either we meant to assign a new value to $x or to create … Continue reading “🔬67. Redeclaration of a symbol in Perl 6”

🔬65. The EVAL routine in Perl 6, part 2

Welcome back! As you might notice, there was a small gap in the daily post flow. Before we are back to the Rakudo internals, a couple of words about some changes here. First of all, every post is now marked with either 🦋 or 🔬 (or with indistinguishable rectangles □ if your browser cannot display an emoji :-). These … Continue reading “🔬65. The EVAL routine in Perl 6, part 2”

🔬61. Declared in BOOTSTRAP

First of all, a new release of the Rakudo Perl 6 compiler was announced today: 2018.02. There are many fixes and speed improvements there, including one proposed by me. Let me not go through the changes, as most of them require quite in-depth knowledge of the Rakudo internals. Instead, let us take a low-hanging fruit and … Continue reading “🔬61. Declared in BOOTSTRAP”

🔬60. Examining the Real role of Perl 6, part 3

As promised yesterday, let us take a look at the two methods of the Real role: polymod and base. polymod I already devoted a post to the Int.polymod method, but the method also exists in the Real role. Let us see if it is different. method polymod(Real:D: +@mods) { my $more = self; my $lazy = … Continue reading “🔬60. Examining the Real role of Perl 6, part 3”