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You're reading from  Perl 6 Deep Dive

Product typeBook
Published inSep 2017
Reading LevelIntermediate
PublisherPackt
ISBN-139781787282049
Edition1st Edition
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Andrew Shitov
Andrew Shitov
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Andrew Shitov

Andrew Shitov has been a Perl enthusiast since the end of the 1990s, and is the organizer of over 30 Perl conferences in eight countries. He worked as a developer and CTO in leading web-development companies, such as Art. Lebedev Studio, Booking dotCom, and eBay, and he learned from the "Fathers of the Russian Internet", Artemy Lebedev and Anton Nossik. Andrew has been following the Perl 6 development since its beginning in 2000. He ran a blog dedicated to the language, published a series of articles in the Pragmatic Perl magazine, and gives talks about Perl 6 at various Perl events. In 2017, he published the Perl 6 at a Glance book by DeepText, which was the first book on Perl 6 published after the first stable release of the language specification.
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Writing our Hello World program

So far, as we have installed the Rakudo Star compiler, it's now time to create the first program in Perl 6. It will print Hello, World! and exit.

The program is really easy. All you need is a single line with the only instruction to call the built-in say function. It takes the string, prints it to the console, and adds a new line after it.

This is how the whole program looks:

say 'Hello, World!'

Save the code to the file, say, hello.pl, and pass it to the compiler as follows:

$ perl6 hello.pl

It will compile the program and immediately execute it. The result is the desired string on the screen:

Hello, World!

Notice that the output ends with a new line. This is the behavior of the built-in say function. Alternatively, we could use another method of printing the output, using the print built-in function. Unlike say, it will not add the new line at the end of the output, so you have to do it yourself by adding the special symbol \n:

print "Hello, World!\n"

Notice that this time, a pair of double quotes is used. Double quotes treat special characters such as \n differently compared to single quotes. Inside double quotes, the \n converts to a new line character. That will not happen in single quotes, and, in that case, \n will appear on the screen as a sequence of two characters, and \n.

Because the program contains only one line of code, it is not necessary to end it with a semicolon. However, you can always do that:

say "Hello, World!";

This program produces exactly the same output as before.

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Author (1)

author image
Andrew Shitov

Andrew Shitov has been a Perl enthusiast since the end of the 1990s, and is the organizer of over 30 Perl conferences in eight countries. He worked as a developer and CTO in leading web-development companies, such as Art. Lebedev Studio, Booking dotCom, and eBay, and he learned from the "Fathers of the Russian Internet", Artemy Lebedev and Anton Nossik. Andrew has been following the Perl 6 development since its beginning in 2000. He ran a blog dedicated to the language, published a series of articles in the Pragmatic Perl magazine, and gives talks about Perl 6 at various Perl events. In 2017, he published the Perl 6 at a Glance book by DeepText, which was the first book on Perl 6 published after the first stable release of the language specification.
Read more about Andrew Shitov