![Auto documentation : Example
multi sub MAIN( :$h? ) is hidden-from-USAGE {
USAGE();
}
multi sub MAIN( :$h!, *@ ) is hidden-from-USAGE {
USAGE();
}
#| Sum up some numbers
multi sub MAIN(
*@nums #= A list of numbers
) {
say [+] @nums;
}
sub USAGE() {
say "Highly useful summing thing";
say $*USAGE;
}
Highly useful summing thing
Usage:
doc.pl6 [<nums> ...] -- Sum up some numbers
[<nums> ...] A list of numbers](https://image.slidesharecdn.com/perl6commandlinescripting-181012075907/85/Perl-6-command-line-scripting-7-320.jpg)
Perl 6 command line scripting
- 1. Perl 6 Command Line Scripting A few tips
- 2. Hi ● Simon Proctor ● Scimon most places (Twitter etc) ● Senior Developer at Zoopla ● Addicted to Perl6
- 3. Command Line Switches ● -e : Same as -E in Perl5. Strict mode on and say works. ● -n : Runs the program with $_ set to each line in the given files. Note newlines are stripped from the input lines. ● -p : As -n then say the value of $_ (calls gist on the value and adds a newline). ● -I path : Adds the path for module searches. ● -M module : Loads the given module prior to running the script. Not included -0, -a, -C, -d, -D, -E, -f, -F, -i, -l, -M-, -s, -S, -t, -T, -u, -U, -X Also available PERL6LIB environment variable useful when using prove
- 4. @*ARGS and $*ARGFILES ● @*ARGS is an Array of all the arguments passed to the programme. ● All arguments are type Str but the Array itself is not typed. ● $*ARGFILES is an IO::CatHandle (actually IO::ArgFiles) object that treats all the values in @*ARGS as paths to files and allows you to iterate over all of them. ● $*ARGFILES is lazily evaluated. It will throw an Exception if the paths do not exist. ● $*ARGFILES is set to $*IN if there are no arguments passed.
- 5. Welcome to MAIN multi sub MAIN( *@files ) {...} multi sub MAIN( $file1, $file2 ) {...} multi sub MAIN( :$s(size) ) {...} ● @*ARGS is mapped into a signature with a few things to bear in mind ○ All inputs a Str typed but if they match a numeric format they may be a subtype : ■ IntStr, RatStr, ComplexStr, NumStr all are both their appropriate types as required ● Named parameters will be either a Scalar or an Array depending on the number of times they are called. ● Named parameters can also be stored in a slurpy hash *%args.
- 6. Auto documentation ● Default response to no matching signature is to call the USAGE sub. ● If you want to call the USAGE sub you need to provide one. ● Default is to output the $*USAGE string. ○ Created by reading documentation on all MAIN subs. ○ #| attaches before the thing being documented ○ #= attached after the thing being documented ○ Both are POD directives and will be included in the documentation ○ To discount a MAIN sub from the $*USAGE string creation give it the trait is hidden-from-USAGE
- 7. Auto documentation : Example multi sub MAIN( :$h? ) is hidden-from-USAGE { USAGE(); } multi sub MAIN( :$h!, *@ ) is hidden-from-USAGE { USAGE(); } #| Sum up some numbers multi sub MAIN( *@nums #= A list of numbers ) { say [+] @nums; } sub USAGE() { say "Highly useful summing thing"; say $*USAGE; } Highly useful summing thing Usage: doc.pl6 [<nums> ...] -- Sum up some numbers [<nums> ...] A list of numbers
- 8. Tips and Tricks ● END and BEGIN phasers and state variables can be very useful with -n and -p ● my %*SUB-MAIN-OPTS = :named-anywhere; ○ Allows named arguments anywhere in the parsing order. ● subtype Single of Any where * !~~ Positional; ○ Use on a named parameter to ensure only one can be passed. ● Subsets::IO includes a number of useful predefined IO subsets ○ E.G. IO::Path::dw for a writable directory ● For larger scripts move the core code into a module and use you script as a launcher