How do I read from STDIN in Rakudo Perl6?

Question

As simple as that, how can I read input from STDIN in Perl6?

I reckon there's many ways of doing it, but I'm interested in the most idiomatic Perl6 solution.

Answer 1

The standard input file descriptor in Perl6 is $*IN (in Perl5 the *STDIN typeglob had a reference to the STDIN file descriptor as *STDIN{IO}).

One way of reading from standard input is the following:

for lines() {
    say "Read: ", $_
}

In fact, lines() without an invocant object defaults to $*IN.lines().

An alternative that uses a local variable is:

for $*IN.lines() -> $line {
    say "Read: ", $line
}

Would be cool to see more alternative ways of doing it.

Answer 2

You can also slurp entire standard input using slurp without arguments. This code will slurp entire input and print it.

print slurp;

If you want to get lines, you can use lines() iterator, working like <> in Perl 5. Please note that unlike Perl 5, it automatically chomps the line.

for lines() {
    say $_;
}

When you want to get single line, instead of using lines() iterator, you can use get.

say get();

If you need to ask user about something, use prompt().

my $name = prompt "Who are you? ";
say "Hi, $name.";