diff options
Diffstat (limited to 'perl6.html.markdown')
| -rw-r--r-- | perl6.html.markdown | 35 |
1 files changed, 23 insertions, 12 deletions
diff --git a/perl6.html.markdown b/perl6.html.markdown index 7485ed57..ee94f5bf 100644 --- a/perl6.html.markdown +++ b/perl6.html.markdown @@ -440,6 +440,7 @@ say @array[^10]; # you can pass arrays as subscripts and it'll return # Note : when reading an infinite list, Perl 6 will "reify" the elements # it needs, then keep them in memory. They won't be calculated more than once. # It also will never calculate more elements that are needed. +# Trying # An array subscript can also be a closure. # It'll be called with the length as the argument @@ -961,10 +962,9 @@ try { use JSON::Tiny; # if you installed Rakudo* or Panda, you'll have this module say from-json('[1]').perl; #=> [1] -# Declare your own packages like this: -# `class Package::Name::Here;` to declare a class, or if you only want to -# export variables/subs, you can use `module`. If you're coming from Perl 5 -# please note you're not usually supposed to use the `package` keyword. +# You should not declare packages using the `package` keyword (unlike Perl 5). +# Instead, use `class Package::Name::Here;` to declare a class, or if you only want to +# export variables/subs, you can use `module`. module Hello::World { # Bracketed form # If `Hello` doesn't exist yet, it'll just be a "stub", @@ -1073,15 +1073,23 @@ ENTER { say "[*] Runs everytime you enter a block, repeats on loop blocks" } LEAVE { say "Runs everytime you leave a block, even when an exception happened. Repeats on loop blocks." } -PRE { say "Asserts a precondition at every block entry, - before ENTER (especially useful for loops)" } +PRE { + say "Asserts a precondition at every block entry, + before ENTER (especially useful for loops)"; + say "If this block doesn't return a truthy value, + an exception of type X::Phaser::PrePost is thrown."; +} # exemple: for 0..2 { PRE { $_ > 1 } # This is going to blow up with "Precondition failed" } -POST { say "Asserts a postcondition at every block exit, - after LEAVE (especially useful for loops)" } +POST { + say "Asserts a postcondition at every block exit, + after LEAVE (especially useful for loops)"; + say "If this block doesn't return a truthy value, + an exception of type X::Phaser::PrePost is thrown, like PRE."; +} for 0..2 { POST { $_ < 2 } # This is going to blow up with "Postcondition failed" } @@ -1522,14 +1530,17 @@ say $0; # The same as above. # IFF it can have more than one element # (so, with `*`, `+` and `**` (whatever the operands), but not with `?`). # Let's use examples to see that: -so 'fooABCbar' ~~ / foo ( A B C )? bar /; # `True` + +# Note: We quoted A B C to demonstrate that the whitespace between them isn't significant. +# If we want the whitespace to *be* significant there, we can use the :sigspace modifier. +so 'fooABCbar' ~~ / foo ( "A" "B" "C" )? bar /; # `True` say $/[0]; #=> ｢ABC｣ say $0.WHAT; #=> (Match) - # It can't be more than one, so it's only a single match object. -so 'foobar' ~~ / foo ( A B C )? bar /; #=> True + # There can't be more than one, so it's only a single match object. +so 'foobar' ~~ / foo ( "A" "B" "C" )? bar /; #=> True say $0.WHAT; #=> (Any) # This capture did not match, so it's empty -so 'foobar' ~~ / foo ( A B C ) ** 0..1 bar /; # `True` +so 'foobar' ~~ / foo ( "A" "B" "C" ) ** 0..1 bar /; # `True` say $0.WHAT; #=> (Array) # A specific quantifier will always capture an Array, # may it be a range or a specific value (even 1). |