Learning Perl 6

Appendix A. Exercise Answers

This appendix contains the answers to the exercises that appear throughout the book.

Answers to Preface Exercises

1. I don’t really have an answer for you here other than what you read immediately before the exercise. The installation of Perl 6 is the hardest part of the problem.

   Once you have perl6, you can ask it for help. The -h and --help command-line switches tend to show you a list of the things you can do with a program. Here’s an extract of the output:

   % perl6 -h
   perl6 [switches] [--] [programfile] [arguments]
   
       With no arguments, enters a REPL. With a "[programfile]" or
       the "-e" option, compiles the given program and, by default,
       also  executes the compiled code.
   
       -c           check syntax only (runs BEGIN and CHECK blocks)
       --doc        extract documentation and print it as text
       -e program   one line of program, strict is enabled by default
       -h, --help   display this help text
       ...
       -v, --version        display version information
       ...

   You see that perl6 has -v and --version switches:

   % perl6 -v
   This is Rakudo version 2018.04 built on MoarVM version 2018.04
   implementing Perl 6.c.

   At the top of that help message was a note about invoking perl6 with no arguments. It drops into the REPL, where you can do the same things I showed you. At the prompt you type out a variable name and the REPL shows you its value:

   % perl6
   To exit type 'exit' or '^D'
   > $*VM
   moar (2018.04)
   > $*PERL
   Perl 6 (6.c)

   There! You’ve completed your first exercise! You know that you have Perl 6 and that it works. You also know ...