diff options
Diffstat (limited to 'raku.html.markdown')
| -rw-r--r-- | raku.html.markdown | 119 |
1 files changed, 59 insertions, 60 deletions
diff --git a/raku.html.markdown b/raku.html.markdown index 4f397589..16035615 100644 --- a/raku.html.markdown +++ b/raku.html.markdown @@ -15,7 +15,7 @@ the JVM and the [MoarVM](http://moarvm.com). Meta-note: -* Although the pound sign (`#`) is used for sentences and notes, Pod-styled +* Although the pound sign (`#`) is used for sentences and notes, Pod-styled comments (more below about them) are used whenever it's convenient. * `# OUTPUT:` is used to represent the output of a command to any standard stream. If the output has a newline, it's represented by the `` symbol. @@ -23,7 +23,7 @@ Meta-note: * `#=>` represents the value of an expression, return value of a sub, etc. In some cases, the value is accompanied by a comment. * Backticks are used to distinguish and highlight the language constructs - from the text. + from the text. ```perl6 #################################################### @@ -95,7 +95,7 @@ my @array = 'a', 'b', 'c'; # equivalent to: my @letters = <a b c>; # In the previous statement, we use the quote-words (`<>`) term for array -# of words, delimited by space. Similar to perl5's qw, or Ruby's %w. +# of words, delimited by space. Similar to perl's qw, or Ruby's %w. @array = 1, 2, 4; @@ -152,7 +152,7 @@ though. =end comment say %hash{'n'}; # OUTPUT: «2», gets value associated to key 'n' say %hash<is-even>; # OUTPUT: «True», gets value associated to key 'is-even' - + #################################################### # 2. Subroutines #################################################### @@ -265,9 +265,9 @@ takes-a-bool('config', :bool); # OUTPUT: «config takes True» takes-a-bool('config', :!bool); # OUTPUT: «config takes False» =begin comment -Since paranthesis can be omitted when calling a subroutine, you need to use -`&` in order to distinguish between a call to a sub with no arguments and -the code object. +Since parenthesis can be omitted when calling a subroutine, you need to use +`&` in order to distinguish between a call to a sub with no arguments and +the code object. For instance, in this example we must use `&` to store the sub `say-hello` (i.e., the sub's code object) in a variable, not a subroutine call. @@ -276,7 +276,7 @@ my &s = &say-hello; my &other-s = sub { say "Anonymous function!" } =begin comment -A sub can have a "slurpy" parameter, or what one'd call a +A sub can have a "slurpy" parameter, or what one'd call a "doesn't-matter-how-many" parameter. This is Raku's way of supporting variadic functions. For this, you must use `*@` (slurpy) which will "take everything else". You can have as many parameters *before* a slurpy one, but not *after*. @@ -284,8 +284,8 @@ else". You can have as many parameters *before* a slurpy one, but not *after*. sub as-many($head, *@rest) { @rest.join(' / ') ~ " !"; } -say as-many('Happy', 'Happy', 'Birthday'); # OUTPUT: «Happy / Birthday !» -say 'Happy', ['Happy', 'Birthday'], 'Day'; # OUTPUT: «Happy / Birthday / Day !» +say as-many('Happy', 'Happy', 'Birthday'); # OUTPUT: «Happy / Birthday !» +say as-many('Happy', ['Happy', 'Birthday'], 'Day'); # OUTPUT: «Happy / Birthday / Day !» # Note that the splat (the *) did not consume the parameter before it. @@ -298,7 +298,7 @@ arguments (or Iterable ones). =end comment sub b(**@arr) { @arr.perl.say }; b(['a', 'b', 'c']); # OUTPUT: «[["a", "b", "c"],]» -b(1, $('d', 'e', 'f'), [2, 3]); # OUTPUT: «[1, ("d", "e", "f"), [2, 3]]» +b(1, $('d', 'e', 'f'), [2, 3]); # OUTPUT: «[1, ("d", "e", "f"), [2, 3]]» b(1, [1, 2], ([3, 4], 5)); # OUTPUT: «[1, [1, 2], ([3, 4], 5)]» =begin comment @@ -508,7 +508,7 @@ given "foo bar" { # can also be a C-style `for` loop: loop { say "This is an infinite loop !"; - last; + last; } # In the previous example, `last` breaks out of the loop very much # like the `break` keyword in other languages. @@ -614,8 +614,8 @@ say Int === Int; # OUTPUT: «True» # Here are some common comparison semantics: # String or numeric equality -say 'Foo' ~~ 'Foo'; # OUTPU: «True», if strings are equal. -say 12.5 ~~ 12.50; # OUTPU: «True», if numbers are equal. +say 'Foo' ~~ 'Foo'; # OUTPUT: «True», if strings are equal. +say 12.5 ~~ 12.50; # OUTPUT: «True», if numbers are equal. # Regex - For matching a regular expression against the left side. # Returns a `Match` object, which evaluates as True if regexp matches. @@ -624,7 +624,7 @@ say $obj; # OUTPUT: «｢a｣» say $obj.WHAT; # OUTPUT: «(Match)» # Hashes -say 'key' ~~ %hash; # OUTPUT:«True», if key exists in hash. +say 'key' ~~ %hash; # OUTPUT: «True», if key exists in hash. # Type - Checks if left side "is of type" (can check superclasses and roles). say 1 ~~ Int; # OUTPUT: «True» @@ -652,7 +652,7 @@ say 'a' le 'b'; # OUTPUT: «True» # 5.2 Range constructor # -say 3 .. 7; # OUTPUT: «3..7», both included. +say 3 .. 7; # OUTPUT: «3..7», both included. say 3 ..^ 7; # OUTPUT: «3..^7», exclude right endpoint. say 3 ^.. 7; # OUTPUT: «3^..7», exclude left endpoint. say 3 ^..^ 7; # OUTPUT: «3^..^7», exclude both endpoints. @@ -665,7 +665,7 @@ say 3.5 ~~ 3 ^.. 7; # OUTPUT: «True», # This is because the range `3 ^.. 7` only excludes anything strictly # equal to 3. Hence, it contains decimals greater than 3. This could -# mathematically be described as 3.5 ∈ (3,7] or in set notation, +# mathematically be described as 3.5 ∈ (3,7] or in set notation, # 3.5 ∈ { x | 3 < x ≤ 7 }. say 3 ^.. 7 ~~ 4 .. 7; # OUTPUT: «False» @@ -769,7 +769,7 @@ sub unpack_array( @array [$fst, $snd] ) { # (^ remember the `[]` to interpolate the array) } unpack_array(@tail); -# OUTPUT: «My first is 3, my second is 3! All in all, I'm 2 3.» +# OUTPUT: «My first is 2, my second is 3! All in all, I'm 2 3.» # If you're not using the array itself, you can also keep it anonymous, # much like a scalar: @@ -800,7 +800,7 @@ fst(1); # OUTPUT: «1» =begin comment You can also destructure hashes (and classes, which you'll learn about later). -The syntax is basically the same as +The syntax is basically the same as `%hash-name (:key($variable-to-store-value-in))`. The hash can stay anonymous if you only need the values you extracted. @@ -842,7 +842,7 @@ my @list3 = list-of(3); #=> (0, 1, 2) # 6.2 Lambdas (or anonymous subroutines) # -# You can create a lambda by using a pointy block (`-> {}`), a +# You can create a lambda by using a pointy block (`-> {}`), a # block (`{}`) or creating a `sub` without a name. my &lambda1 = -> $argument { @@ -858,18 +858,18 @@ my &lambda3 = sub ($argument) { } =begin comment -Both pointy blocks and blocks are pretty much the same thing, except that +Both pointy blocks and blocks are pretty much the same thing, except that the former can take arguments, and that the latter can be mistaken as -a hash by the parser. That being said, blocks can declare what's known +a hash by the parser. That being said, blocks can declare what's known as placeholders parameters through the twigils `$^` (for positional -parameters) and `$:` (for named parameters). More on them latern on. +parameters) and `$:` (for named parameters). More on them later on. =end comment my &mult = { $^numbers * $:times } say mult 4, :times(6); #=> «24» # Both pointy blocks and blocks are quite versatile when working with functions -# that accepts other functions such as `map`, `grep`, etc. For example, +# that accepts other functions such as `map`, `grep`, etc. For example, # we add 3 to each value of an array using the `map` function with a lambda: my @nums = 1..4; my @res1 = map -> $v { $v + 3 }, @nums; # pointy block, explicit parameter @@ -1088,7 +1088,7 @@ sub call_say_dyn { # $*dyn_scoped 1 and 2 will be looked for in the call. say_dyn(); # OUTPUT: «25 100» - + # The call to `say_dyn` uses the value of $*dyn_scoped_1 from inside # this sub's lexical scope even though the blocks aren't nested (they're # call-nested). @@ -1162,7 +1162,7 @@ class Human { }; # Create a new instance of Human class. -# NOTE: Only attributes declared with the `.` twigil can be set via the +# NOTE: Only attributes declared with the `.` twigil can be set via the # default constructor (more later on). This constructor only accepts named # arguments. my $person1 = Human.new( @@ -1317,7 +1317,7 @@ method on the `$_` variable to access the exception open 'foo' orelse say "Something happened {.exception}"; # This also works: -open 'foo' orelse say "Something happened $_"; +open 'foo' orelse say "Something happened $_"; # OUTPUT: «Something happened Failed to open file foo: no such file or directory» =begin comment @@ -1431,15 +1431,15 @@ use JSON::Tiny; # if you installed Rakudo* or Panda, you'll have this module say from-json('[1]').perl; # OUTPUT: «[1]» =begin comment -You should not declare packages using the `package` keyword (unlike Perl 5). +You should not declare packages using the `package` keyword (unlike Perl). Instead, use `class Package::Name::Here;` to declare a class, or if you only want to export variables/subs, you can use `module` instead. =end comment # If `Hello` doesn't exist yet, it'll just be a "stub", that can be redeclared -# as something else later. +# as something else later. module Hello::World { # bracketed form - # declarations here + # declarations here } # The file-scoped form which extends until the end of the file. For @@ -1520,7 +1520,7 @@ fixed-rand for ^10; # will print the same number 10 times for ^5 -> $a { sub foo { # This will be a different value for every value of `$a` - state $val = rand; + state $val = rand; } for ^5 -> $b { # This will print the same value 5 times, but only 5. Next iteration @@ -1558,9 +1558,9 @@ END { say "Runs at run time, as late as possible, only once" } # # 14.3 Block phasers # -ENTER { say "[*] Runs everytime you enter a block, repeats on loop blocks" } +ENTER { say "[*] Runs every time you enter a block, repeats on loop blocks" } LEAVE { - say "Runs everytime you leave a block, even when an exception + say "Runs every time you leave a block, even when an exception happened. Repeats on loop blocks." } @@ -1610,7 +1610,7 @@ for ^5 { # # 14.6 Role/class phasers # -COMPOSE { +COMPOSE { say "When a role is composed into a class. /!\ NOT YET IMPLEMENTED" } @@ -1619,9 +1619,9 @@ say "This code took " ~ (time - CHECK time) ~ "s to compile"; # ... or clever organization: class DB { - method start-transaction { say "Starting transation!" } - method commit { say "Commiting transaction..." } - method rollback { say "Something went wrong. Rollingback!" } + method start-transaction { say "Starting transaction!" } + method commit { say "Committing transaction..." } + method rollback { say "Something went wrong. Rolling back!" } } sub do-db-stuff { @@ -1647,7 +1647,7 @@ braces `{` and `}`. =end comment # -# 15.1 `do` - It runs a block or a statement as a term. +# 15.1 `do` - It runs a block or a statement as a term. # # Normally you cannot use a statement as a value (or "term"). `do` helps @@ -1805,7 +1805,7 @@ sub postfix:<!>( Int $n ) { } say 5!; # OUTPUT: «120» -# Postfix operators ('after') have to come *directly* after the term. +# Postfix operators ('after') have to come *directly* after the term. # No whitespace. You can use parentheses to disambiguate, i.e. `(5!)!` sub infix:<times>( Int $n, Block $r ) { # infix ('between') @@ -1898,7 +1898,7 @@ say [+] (); # OUTPUT: «0», empty sum say [//]; # OUTPUT: «(Any)» # There's no "default value" for `//`. -# You can also use it with a function you made up, +# You can also use it with a function you made up, # You can also surround using double brackets: sub add($a, $b) { $a + $b } say [[&add]] 1, 2, 3; # OUTPUT: «6» @@ -2078,19 +2078,19 @@ say so 'abc' ~~ / a b+ c /; # OUTPUT: «True», one is enough say so 'abbbbc' ~~ / a b+ c /; # OUTPUT: «True», matched 4 "b"s # `*` - zero or more matches -say so 'ac' ~~ / a b* c /; # OUTPU: «True», they're all optional -say so 'abc' ~~ / a b* c /; # OUTPU: «True» -say so 'abbbbc' ~~ / a b* c /; # OUTPU: «True» -say so 'aec' ~~ / a b* c /; # OUTPU: «False», "b"(s) are optional, not replaceable. +say so 'ac' ~~ / a b* c /; # OUTPUT: «True», they're all optional +say so 'abc' ~~ / a b* c /; # OUTPUT: «True» +say so 'abbbbc' ~~ / a b* c /; # OUTPUT: «True» +say so 'aec' ~~ / a b* c /; # OUTPUT: «False», "b"(s) are optional, not replaceable. # `**` - (Unbound) Quantifier # If you squint hard enough, you might understand why exponentation is used # for quantity. -say so 'abc' ~~ / a b**1 c /; # OUTPU: «True», exactly one time -say so 'abc' ~~ / a b**1..3 c /; # OUTPU: «True», one to three times -say so 'abbbc' ~~ / a b**1..3 c /; # OUTPU: «True» -say so 'abbbbbbc' ~~ / a b**1..3 c /; # OUTPU: «Fals», too much -say so 'abbbbbbc' ~~ / a b**3..* c /; # OUTPU: «True», infinite ranges are ok +say so 'abc' ~~ / a b**1 c /; # OUTPUT: «True», exactly one time +say so 'abc' ~~ / a b**1..3 c /; # OUTPUT: «True», one to three times +say so 'abbbc' ~~ / a b**1..3 c /; # OUTPUT: «True» +say so 'abbbbbbc' ~~ / a b**1..3 c /; # OUTPUT: «Fals», too much +say so 'abbbbbbc' ~~ / a b**3..* c /; # OUTPUT: «True», infinite ranges are ok # # 18.2 `<[]>` - Character classes @@ -2150,7 +2150,7 @@ say so 'fooABCABCbar' ~~ / foo ( 'A' <[A..Z]> 'C' ) + bar /; # OUTPUT: «True say $/; # Will either print the matched object or `Nil` if nothing matched. # As we also said before, it has array indexing: -say $/[0]; # OUTPUT: «｢ABC｣ ｢ABC｣», +say $/[0]; # OUTPUT: «｢ABC｣ ｢ABC｣», # The corner brackets (｢..｣) represent (and are) `Match` objects. In the # previous example, we have an array of them. @@ -2202,8 +2202,8 @@ say $/[0].list.perl; # OUTPUT: «(Match.new(...),).list» # Alternation - the `or` of regexes # WARNING: They are DIFFERENT from PCRE regexps. -say so 'abc' ~~ / a [ b | y ] c /; # OUTPU: «True», Either "b" or "y". -say so 'ayc' ~~ / a [ b | y ] c /; # OUTPU: «True», Obviously enough... +say so 'abc' ~~ / a [ b | y ] c /; # OUTPUT: «True», Either "b" or "y". +say so 'ayc' ~~ / a [ b | y ] c /; # OUTPUT: «True», Obviously enough... # The difference between this `|` and the one you're used to is # LTM ("Longest Token Matching") strategy. This means that the engine will @@ -2218,7 +2218,7 @@ To decide which part is the "longest", it first splits the regex in two parts: yet introduced), literals, characters classes and quantifiers. * The "procedural part" includes everything else: back-references, - code assertions, and other things that can't traditionnaly be represented + code assertions, and other things that can't traditionally be represented by normal regexps. Then, all the alternatives are tried at once, and the longest wins. @@ -2268,7 +2268,7 @@ while its absence falseness). For example: # convert to IO object to check the file exists subset File of Str where *.IO.d; - + multi MAIN('add', $key, $value, Bool :$replace) { ... } multi MAIN('remove', $key) { ... } multi MAIN('import', File, Str :$as) { ... } # omitting parameter name @@ -2358,7 +2358,7 @@ side, once its left side changed: # In this case the right-hand-side wasn't tested until `$_` became "C" # (and thus did not match instantly). -.say if 'B' fff 'B' for <A B C B A>; #=> «B C B», +.say if 'B' fff 'B' for <A B C B A>; #=> «B C B», # A flip-flop can change state as many times as needed: for <test start print it stop not printing start print again stop not anymore> { @@ -2392,21 +2392,20 @@ resource on Raku. If you are looking for something, use the search bar. This will give you a dropdown menu of all the pages referencing your search term (Much better than using Google to find Raku documents!). -- Read the [Raku Advent Calendar](http://perl6advent.wordpress.com/). This +- Read the [Raku Advent Calendar](https://rakuadventcalendar.wordpress.com/). This is a great source of Raku snippets and explanations. If the docs don't describe something well enough, you may find more detailed information here. This information may be a bit older but there are many great examples and explanations. Posts stopped at the end of 2015 when the language was declared -stable and Raku 6.c was released. +stable and `Raku v6.c` was released. -- Come along on `#raku` at `irc.freenode.net`. The folks here are +- Come along on `#raku` at [`irc.freenode.net`](https://webchat.freenode.net/?channels=#raku). The folks here are always helpful. - Check the [source of Raku's functions and -classes](https://github.com/rakudo/rakudo/tree/nom/src/core). Rakudo is +classes](https://github.com/rakudo/rakudo/tree/master/src/core.c). Rakudo is mainly written in Raku (with a lot of NQP, "Not Quite Perl", a Raku subset easier to implement and optimize). - Read [the language design documents](https://design.raku.org/). They explain Raku from an implementor point-of-view, but it's still very interesting. - |