Perl 6
Perl 6 Lookup Tablet: Revision 153
"Overview"[Perl 6 Tablets] - _Chapter:_ "0:History"[Perl 6 History Tablet], "1:Design"[Perl 6 Language Design Tablet], "2:Basics"[Perl 6 Basics Tablet], "3:Var"[Perl 6 Variable Tablet], "4:Op"[Perl 6 Operator Tablet], "5:IO"[Perl 6 IO Tablet], "6:{}"[Perl 6 Block Tablet], "7:Sub"[Perl 6 Subroutine Tablet], "8:OOP"[Perl 6 OOP Tablet], "9:Rx"[Perl 6 Regex Tablet], "10:Meta"[Perl 6 Meta Tablet]
"Intro"[Perl 6 Intro Tablet] - _Appendices:_ "A:Index"[Perl 6 Index Tablet], *"B:Tables"[Perl 6 Lookup Tablet]*, "C:Cook"[Perl 6 Cookbook Tablet], "D:Delta"[Perl 6 Delta Tablet], "E:Best of"[Best Of Perl 6 Tablet], "F:Links"[Perl 6 Links Tablet]

----

{toc: }

^^ Variables

^^^ Sigils

All variables in Perl begin with a sigil. They mark the 3 primary var types. The 4th sigil is for callables (routines) and the 5th is for layers (namespaces) that organize the previous 4.

> $. . . . "scalar"{link: [Perl 6 Variable Tablet]scalar}, single value, can be of any data type
> @ . . . ordered "array"{link: [Perl 6 Variable Tablet]array}, indexed list of scalar
> % . . . unordered "hash"{link: [Perl 6 Variable Tablet]hash} (associative array), 2 column table with unique IDs (keys) and associated values (value)
> &. . . . code/rule/token/regex
> :: . . . abstraction: package/module/class/role/subset/enum/type/grammar

The first 4 can also be used as prefix operators, called {link: contextualizers}, that force different contexts, but there are much more different contexts then 4.

^^^ Twigils

Twigil is short for secondary sigil. They follow after a primary sigil and mark special namespaces or variables with special meanings and properties.

> $foo . . . ordinary scoping (no twigil)
> $.foo. . . object attribute public accessor
> $!foo. . . object attribute private storage
> $^foo . . self-declared formal positional parameter
> $:foo . . .self-declared formal named parameter
> $*foo . . .contextualizable global variable
> $?foo . . .compiler hint variable
> $=foo . . .pod variable
> $<foo> . .match variable, short for $/<foo> or even $/{'foo'}
> $~foo . . .the foo sublanguage seen by the parser at this lexical spot

^^^ Special Variables

> $_. . . . . . . . . context variable
> $! . . . . . . . . . error msg
> -
> $/ . . . . . . . . . last created match object of this block
> $<...> . . . . . . alias to named capture, see Twigils above
> $0 .. $9 . . . . . alias to positional capture (most like in P5 - $1 .. $9)
> @() . . . . . . . . array that holds $0 .. $9 and rest and positional submatches
> -
> $*EXECUTABLE_NAME . former $0
> @*ARGS . . . . . Arguments (Parameter) to a program (script), formerly @ARGV
> $*ARGFILES. . . magic command-line input handle
> $*CWD . . . . . . current working directory (Str)
> $*IN. . . . . . . . standard input handle (command line mostly)
> $*OUT. . . . . . . standard output (command line mostly)
> $*ERR. . . . . . . standard error output (command line mostly)
> $*PERL. . . . . . perl version running under, was formerly $^V or $]
> $*LANG. . . . . . LANG variable from %*ENV that defines what human language is used
> @*INC . . . . . . include pathes (but not for std library modules), formerly @INC
> $*KERNEL . . . . operating system running under
> $*DISTRO . . . . SoftwarePackage # Which OS distribution am I running under
> $*PID . . . . . . . ID of the running process,
> $*GID . . . . . . . real global ID of the running process owner, formerly @(
> $*UID . . . . . . . real user ID of the running process owner (user), formerly @<
> $*EGID . . . . . . effective global ID, formerly @)
> $*EUID . . . . . . effective user ID, formerly @>
> $*ON_WARN. . . formerly $SIG{__WARN__}
> $*ON_DIE. . . . . formerly $SIG{__DIE__}
> $*EMERGENCY_MEMORY. . . formerly $^M
> %*ENV. . . . . . . formerly %ENV
> $*KERNEL. . . . . SoftwarePackage # operating system running under
> $*DISTRO . . . . . SoftwarePackage # Which OS distribution am I running under
> $*TZ . . . . . . . . local time zone
> $*COMPILING . . .
> $*DEBUGGING . .
> -
> $?KERNEL . . . . . for which operating System was this program compiled?
> $?DISTRO . . . . . Which OS distribution am I compiling under?
> $?ARCH. . . . . . . SoftwarePackage # Host architecture
> $?XARCH. . . . . . SoftwarePackage # Target architecture
> $?VM . . . . . . . . Which virtual machine am I compiling under
> $?XVM . . . . . . . Which virtual machine am I cross-compiling for
> $?PERL . . . . . . . Which Perl am I compiled for?
> %?LANG . . . . . . Hash of Grammar # What is the current set of interwoven languages?
> $?GRAMMAR. . . . current grammar
> $?FILE . . . . . . . current filename of source file
> $?MODULE. . . . . current module
> $?PACKAGE . . . . current package
> ::?CLASS . . . . . current class (as package name)
> $?CLASS. . . . . . current class
> @?CLASS . . . . . current classes
> $?ROLE . . . . . . . current role (as variable)
> @?ROLE . . . . . . current roles
> &?ROUTINE . . . . current sub or methode
> @?ROUTINE . . . . current subs or methods
> &?BLOCK . . . . . . reference to current block
> $?LINE. . . . . . . . current line number
> -
> @=COMMENT. . . All the comment blocks in the file
> $=DATA . . . . . . data block handle (=begin DATA ... =end)
> @=DATA. . . . . . Same as above, but array
> -
> $~MAIN . . . . . . the current main language (e.g. Perl statements)
> $~Q. . . . . . . . . the current root of quoting language
> $~Quasi . . . . . . the current root of quasiquoting language
> $~Regex . . . . . .the current root of regex language
> $~Trans . . . . . . the current root of transliteration language
> $~P5Regex . . . . the current root of the Perl regex language

^^^ Scope Declarator

> my . . . . . . . introduces lexically scoped names
> our . . . . . . . introduces package-scoped names
> has . . . . . . . introduces attribute names
> anon . . . . . . introduces names that aren't to be stored anywhere
> state . . . . . . introduces lexically scoped but persistent names
> augment. . . . adds definitions to an existing name
> supersede. . . replaces definitions of an existing name

^^^ Scopes

> The following pseudo-package names are reserved at the front of a name:
> .
> MY . . . . . . Symbols in the current lexical scope (aka $?SCOPE)
> OUR. . . . . . Symbols in the current package (aka $?PACKAGE)
> .
> CORE. . . . . Outermost lexical scope, definition of standard Perl
> GLOBAL . . . Interpreter-wide package symbols, really CORE::GLOBAL
> PROCESS . . Process-related globals (superglobals), CORE::PROCESS
> COMPILING . Lexical symbols in the scope being compiled
> DYNAMIC . . Contextual symbols in my or any caller's lexical scope
> .
> The following relative names are also reserved but may be used anywhere in a name:
> .
> CALLER. . . . Contextual symbols in the immediate caller's lexical scope
> OUTER . . . . Symbols in the next outer lexical scope
> UNIT . . . . . Symbols in the outermost lexical scope of compilation unit
> SETTING. . . Lexical symbols in the unit's DSL (usually CORE)
> PARENT . . . Symbols in this package's parent package (or lexical scope)
> .
> The following is reserved at the beginning of method names in method calls:
> .
> SUPER . . . . Package symbols declared in inherited classes

^^^ low level data types

This is more low level than the last table. These types are more meant to give the compiler optimizing hints.

> int1 . .
> int2 . .
> int4 . .
> int8 . .
> int16 . .
> int32 . . (aka int on 32-bit machines)
> int64 . . (aka int on 64-bit machines)
> uint1 . . (aka bit)
> uint2 . .
> uint4 . .
> uint8 . . (aka byte)
> uint16. .
> uint32. .
> uint64. .
> num32 . .
> num64 . . (aka num on most architectures)
> num128 . .
> complex32 .
> complex64 . (aka complex on most architectures)
> complex128 .
> Str . . .

^^^ Value Types

In Perl 6 any variable and value is an object. Here's a list of all different types of values, represented my different classes or roles. The "routine types"{link: routine_types} are in a different section.

^^^^ Undefined types

> Mu. . . . . . . . Most Undefined
> Failure . . . . . Failure (lazy exceptions, thrown if not handled properly)
> Any . . . . . . . Perl 6 object (default routine parameter type, excludes junction)
> Cool. . . . . . . Perl 6 Convenient OO Loopbacks
> Whatever . . . Wildcard (like Any, but subject to do-what-I-mean via MMD)
> Int. . . . . . . . Any Int object
> Widget . . . . . Any Widget object

^^^^ Immutable types

> Str. . . . . . Perl string (finite sequence of Unicode characters)
> Bit . . . . . . Perl single bit (allows traits, aliasing, undef, etc.)
> Int. . . . . . Perl integer (allows Inf/NaN, arbitrary precision, etc.)
> Num. . . . . Perl number (approximate Real, generally via floating point)
> Rat . . . . . Perl rational (exact Real, limited denominator)
> FatRat . . . Perl rational (unlimited precision in both parts)
> Complex . . Perl complex number
> Bool. . . . . Perl boolean
> .
> Exception . Perl exception
> Block . . . . Executable objects that have lexical scopes
> Seq . . . . . A list of values (can be generated lazily)
> Range. . . . A pair of ordered endpoints
> .
> Set . . . . . Unordered collection of values that allows no duplicates
> Bag . . . . . Unordered collection of values that allows duplicates
> Enum . . . . An immutable Pair
> EnumMap. . A mapping of Enums with no duplicate keys
> Signature. . Function parameters (left-hand side of a binding)
> Parcel. . . . Arguments in a comma list
> LoL. . . . . . Arguments in a semicolon list (or equiv, like Z)
> Capture. . . Function call arguments (right-hand side of a binding)
> Blob . . . . . An undifferentiated mass of bits
> Instant . . . A point on the continuous atomic timeline
> Duration. . . The difference between two Instants
> HardRoutine A routine that is committed to not changing

^^^^ Mutable types

> Iterator . . . . Perl list
> SeqIter . . . . Iterator over a Seq
> RangeIter. . . Iterator over a Range
> Scalar . . . . . Perl scalar
> Array. . . . . . Perl array
> Hash . . . . . . Perl hash
> KeySet. . . . . KeyHash of Bool (does Set in list/array context)
> KeyBag. . . . . KeyHash of UInt (does Bag in list/array context)
> Pair . . . . . . . A single key-to-value association
> PairSeq. . . . . A Seq of Pairs
> Buf . . . . . . . Perl buffer (a stringish array of memory locations)
> IO. . . . . . . . Perl filehandle
> Routine . . . . Base class for all wrappable executable objects
> Sub. . . . . . . Perl subroutine
> Method . . . . Perl method
> Submethod. . Perl subroutine acting like a method
> Macro . . . . . Perl compile-time subroutine
> Regex . . . . . Perl pattern
> Match . . . . . Perl match, usually produced by applying a pattern
> Stash. . . . . . A symbol table hash (package, module, class, lexpad, etc)
> SoftRoutine. . A routine that is committed to staying mutable

^^^ Object Introspection

> WHAT. . . . . short name of the class that an object belongs to
> WHICH . . . . object ID (type)
> WHO. . . . . . package, that support that object, long name in string context
> WHERE . . . . memory address of the object
> HOW. . . . . . object of meta class: "Higher Order Workings"
> WHEN. . . . . (reserved for events?)
> WHY. . . . . . (reserved for documentation)
> WHENCE . . . autovivification of closures

^^ Operators

^^^ Table of precedence

> A . Level . . . . . . . . . . . . Examples
> = . =========== . . . ==================
> N . Terms . . . . . . . . . 42 3.14 "eek" qq["foo"] $x :!verbose @$array
> L . Method postfix. . . . meth .+ .? .* .() .[] .{} .<> .<<>> .:: .= .^ .:
> N . Autoincrement. . . . ++ --
> R . Exponentiation. . . . **
> L . Symbolic unary. . . . ! + - ~ ? | +^ ~^ ?^ ^
> L . Multiplicative . . . . . * / % +& +< +> ~& ~< ~> ?& div mod
> L . Additive . . . . . . . . + - +| +^ ~| ~^ ?| ?^
> L . Replication. . . . . . . x xx
> X . Concatenation . . . . ~
> X . Junctive and . . . . . & also
> X . Junctive or . . . . . . | ^
> L . Named unary . . . . . sleep abs sin temp let
> N . Nonchaining infix. . . but does <=> leg cmp .. ..^ ^.. ^..^
> C . Chaining infix . . . . . != == < <= > >= eq ne lt le gt ge ~~ === eqv !eqv
> X . Tight and. . . . . . . . &&
> X . Tight or. . . . . . . . . || ^^ // min max
> R . Conditional. . . . . . . ?? !! ff fff
> R . Item assignment . . . = := ::= => += -= **= xx= .=
> L . Loose unary . . . . . . true not
> X . Comma operator . . . , :
> X . List infix. . . . . . . . . Z minmax X X~ X* Xeqv ...
> R . List prefix. . . . . . . . print push say die map substr ... {{[+] [*]}} any $ @
> X . Loose and . . . . . . . and andthen
> X . Loose or . . . . . . . . or xor orelse
> X . Sequencer. . . . . . . <==, ==>, <<==, ==>>
> N . Terminator. . . . . . . ; {...}, unless, extra ), ], }

^^^ Operator Associativity

| | Assoc | Meaning of $a ! $b ! $c |
| L | left | ($a ! $b) ! $c |
| R | right | $a ! ($b ! $c) |
| N | non | ILLEGAL |
| C | chain | ($a ! $b) and ($b ! $c) |
| X | list | infix:<!>($a; $b; $c) |

^^^ Categories

These are the categories of the main language grammar. Sublanguages such as quoting and regexes can provide their own.

> category:<prefix>
> circumfix:<( )>
> dotty:<.>
> infix:<+>
> infix_circumfix_meta_operator:{'»','«'}
> infix_postfix_meta_operator:<=>
> infix_prefix_meta_operator:<!>
> package_declarator:<class>
> postcircumfix:<( )>
> postfix:<++>
> postfix_prefix_meta_operator:{'»'}
> prefix:<++>
> {{prefix_circumfix_meta_operator:{'[',']'} }}
> prefix_postfix_meta_operator:{'«'}
> quote:<q>
> routine_declarator:<sub>
> scope_declarator:<my>
> sigil:<$>
> special_variable:<$!>
> statement_control:<if>
> statement_mod_cond:<if>
> statement_mod_loop:<while>
> statement_prefix:<do>
> term:<*>
> trait_auxiliary:<is>
> trait_verb:<of>
> twigil:<?>
> type_declarator:<subset>
> version:<v>

^^^ Metaoperators

M. appear mostly before or around regular operators and give them different meaning or greater range.
They can be nested like _@a X[+=] @b_, but be careful with that.
In the example V stands for Value, L for left Value, and R for right. A number is the array index.
Words in the second column are short explanation or an aliasing method if followed by ().

> {{op=}} . . . self assign. . . known from P5, {{$L <op>= $R}} equals {{$L = $L op $R}}
> {{!op}}. . . . negation. . . . known from P5, {{$L !<op> $R}} equals {{!($L op $R)}}
> {{Rop}} . . . reverse. . . . . reverses the order of the operands
> {{Sop}} . . . sequence . . . like reduction, only synchronous, execution in listed order is guaranteed; suppresses any explicit or implicit parallelism
> {{>>op}} . . hyper . . . . . . processes arrays eager and in parallel or applies a single value to all array elements;
> . . . . . . . . . . . . . . . . . @E = $L[0] op $R[0], $L[1] op $R[1], ...;
> {{<<op}} . . hyper . . . . . . like above, points to the side which determines dimensionality;
> . . . . . . . . . . . . . . . . . @E = $L[0] op $R[0], $L[1] op $R[1], ...;
> {{[op]}}. . . reduce() . . . . applies the operator between all elements of an array;
> . . . . . . . . . . . . . . . . . $result = $V[0] op $V[1] op ...;
> {{[\op]}} . . triangle(). . . . applies above reduction to a series of lists made of array slices ranging in length from 1 to the complete length of the original list;
> . . . . . . . . . . . . . . . . . @result = $V[0], $V[0] op $V[1], $V[0] op $V[1] op $V[2], ...;
> {{Xop}} . . . crosswith(). . . performs the operator to all the pairs of the Cartesian product of two arrays;
> . . . . . . . . . . . . . . . . . @result = $L[0] op $R[0], $L[0] op $R[1], $L[1] op $R[0], $L[1] op $R[1]
> {{Zop}} . . . zipwith() . . . . like hyper, but evaluates lazy
> . . . . . . . . . . . . . . . . . @result = $L[0] op $R[0], $L[1] op $R[1], ...

^^^ Unicode operators

The two hyper operators can be written with the Unicode "chevron" signs (also documented as "French Quotes") or with double less than or greater than signs (documented as "Texas Quotes").

> « aka {{<<}}
> » aka {{>>}}

^^^ Contextualizers

Infix operator or functions that forcing a context.

> $(). . . . item(). . . . . "scalar/item context"{link: [Perl 6 Variable Tablet] Scalar}
> @() . . . list(), . . . . . "array/list context"{link: [Perl 6 Variable Tablet] Array}
> %() . . . hash(). . . . . "hash context"{link: [Perl 6 Variable Tablet] Hash}
> . . . . . . flat(). . . . . . flat list
> . . . . . . lol() . . . . . . list of list (was slice context before)
> |. . . . . . . . . . . . . . . flatten "capture"{link: [Perl 6 Variable Tablet] capture} object into arglist (named parameter)
> || . . . . . . . . . . . . . . flatten "capture"{link: [Perl 6 Variable Tablet] capture} object into semicolon list (positional parameter)
> ?. . . . . . . . . . . . . . . "boolean"{link: [Perl 6 Operator Tablet] bool context}
> + . . . . . . . . . . . . . . "numeric"{link: [Perl 6 Operator Tablet] numeric context}
> ~ . . . . . . . . . . . . . . "string"{link: [Perl 6 Operator Tablet] string context}
> &() . . . . . . . . . . . . . "coderef"{link: [Perl 6 Variable Tablet] Callable}, routines

^^^ Filetest Ops

Use it as in "$file.:X" or "$file ~~ :X". (NOTE 2010-11-07: in rakudo this is "$filename.IO ~~ :X")

> :r . . . file is readable by effective uid/gid.
> :w. . . file is writeable by effective uid/gid.
> :x . . . file is executable by effective uid/gid.
> :o . . . file is owned by effective uid.
> .
> :R . . . file is readable by real uid/gid.
> :W . . . file is writeable by real uid/gid.
> :X . . . file is executable by real uid/gid.
> :O . . . file is owned by real uid.
> .
> :e . . . file exists
> :s . . . file has size greater than 0
> .
> :f . . . file is a plain file.
> :d . . . file is a directory.
> :l . . . file is a symbolic link.
> :p . . . file is a named pipe (FIFO), or filehandle is a pipe.
> :S . . . file is a socket.
> :b . . . file is a block special file.
> :c . . . file is a character special file.
> :t . . . filehandle is opened to a tty.
> .
> :u . . . file has setuid bit set.
> :g . . . file has setgid bit set.
> :k . . . file has sticky bit set.

^^^ Smartmatch

When used as infix $_ is the left side, X is right. In when clauses just X is stated.

| $_ | X | Type of Match Wanted | What to use on the right |
| Array | Num | array element truth | {{.[X]}} |
| Array | Num | array contains number | {{*,X,*}} |
| Array | Str | array contains string | {{*,X,*}} |
| Array | Seq | array begins with seq | {{X,*}} |
| Array | Seq | array contains seq | {{*,X,*}} |
| Array | Seq | array ends with seq | *,X |
| Hash | Str | hash element truth | .{X} |
| Hash | Str | hash key existence | .{X}:exists |
| Hash | Num | hash element truth | .{X} |
| Hash | Num | hash key existence | .{X}:exists |
| Buf | Int | buffer contains int | .match(X) |
| Str | Char | string contains char | .match(X) |
| Str | Str | string contains string | .match(X) |
| Array | Scalar | array contains item | .any === X |
| Str | Array | array contains | string X.any |
| Num | Array | array contains | number X.any |
| Scalar | Array | array contains object | X.any |
| Hash | Array | hash slice exists | .{X.all}:exists .{X.any}:exists |
| Set | Set | subset relation | .{X}:exists |
| Set | Hash | subset relation | .{X}:exists |
| Any | Set | subset relation | .Set.{X}:exists |
| Any | Hash | subset relation | .Set.{X}:exists |
| Any | Set | superset relation | X.{$_}:exists |
| Any | Hash | superset relation | X.{$_}:exists |
| Any | Set | sets intersect | .{X.any}:exists |
| Set | Array | subset relation | X,* # (conjectured) |
| Array | Regex | match array as string | .Cat.match(X); cat(@$_).match(X) |

^^^ Quoting Ops

The "basic quoting operator"{link: [perl_6_basics_tablet]quoting} (Q) does nothing, just taking literally what you quoted as a string. But with several adverbs, it behaves like the well known following ops:

| q// | Q :q // |
| ' ' | Q :q // |
| qq// | Q :qq // |
| " " | Q :qq // |
| qw// | Q :q :w // |
| {{< >}} | Q :q :w // |
| {{<< >>}} | Q :qq :ww // |
| qp// | Q :path // |
| qx// | Q :exec // |
| rx// | Q :regex // |
| m// | Q :match // |
| ms// | Q :match :sigspace // |
| s/// | Q :subst /// |
| ss/// | Q :subst :samespace /// |
| tr/// | Q :trans /// |

^^ Text Processing

^^^ Quoting Adverbs

There are a lot more adverbs to fine tune your quoting. The Adverbs can used with any quoting operator like: Q :s/.../ or qq :p /.../.

| Short | Long | Meaning |
| :q | :single | Interpolate \\, \q and \' (or whatever) |
| :qq | :double | Interpolate with :s, :a, :h, :f, :c, :b |
| :s | :scalar | Interpolate $ vars |
| :a | :array | Interpolate @ vars |
| :h | :hash | Interpolate % vars |
| :f | :function | Interpolate & calls |
| :c | :closure | Interpolate {...} expressions |
| :b | :backslash | Interpolate "\n, \t, etc."{link: Escape Sequences} (implies :q at least) |
| :w | :words | Split result on words (no quote protection) |
| :ww | :quotewords | Split result on words (with quote protection) |
| :p | :path | Return a Path object (see S16 for more options) |
| :to | :heredoc | Parse result as heredoc terminator |
| :x | :exec | Execute as command and return results |
| | :code | Quasiquoting |
| | :regex | Parse as regex |
| | :subst | Parse as substitution |
| | :trans | Parse as transliteration |

^^^ Regex Modifier

Stay behind the regex op and change the behaviour of the regex, search scope, etc.

| Short | Long | Meaning |
| :g | :global | searches for any finding |
| :x(n) | | searches n times (n is an int) |
| :nth(n) | :st :nd :rd | demands the nth finding, has many aliases for correct spelling (:2nd) |
| :c(n) | :continue | searches from nth position (counting from 0) |
| :p(n) | :pos | searches only on nth position (counting from 0) |
| :ov | :overlap | searches on all positionens just one time (activates backtracking) |
| :ex | :exhaustive | searches on all positions as long as it findes something (activates backtracking) |
| | :ratchet | deactivates backtracking |
| | :panic | overwriting of possible set :ratchet for all subrules (activates backtracking) |
| | :keepall | subrules have to memorize everything |
| :rw | | the regex has the right to change the string |
| :s | :sigspace | whitespace just separate parts of the Regex, don't stand for spaces to look for |
| :ss | :samespace | as in :s for substitutions, 1st part replaced with 1st part in second half a.s.o. (ss/teh hsa/the has/;) |
| :i | :ignorecase | no distinctions between uppercase and lowercase |
| :ii | :samecase | substitute with chars of same case as the matching |
| :m | :ignoremark | comparing base characters (Unicode non-mark characters) while ignoring any trailing mark characters |
| :mm | :samemark | substitute with chars that has same mark/accent pattern as the matched string |
| | :bytes | searches on byte level |
| | :chars | searches on character level (default) |
| | :codes | matches between codepoints |
| | :graphs | match language-independent graphemes |
| :P5 | :Perl5 | use the old Regex |

^^^ Regex Metacharacter

> . _______ any character
> ^ ______ begin of the sring
> ^^ _____ begin of a line
> $ _______ end of the string
> $$ ______ end of a line
> (...)_____ group patterns and capture the result
> {{[...]}} _____group patterns without capturing
> {...} ____ execute a closure (Perl 6 code) within a rule
> <...> ____match a subrule (assertion
> | _______ match alternate patterns (logigical OR with LTM)
> || ______ match alternate patterns (sequential OR)
> & _______ match multiple patterns (AND)
> ** ______ muliply this (meta)char/subrule times the following digit on right side
> % ______ match this (meta)char/subrule as long as separated by (meta)char/subrule on the right
> %% ____ like %, but allows trailing separator
> \ _______ escape a metacharacter to get a literal character, or escape a literal character to get a metacharacter
> # _______ mark a comment (to the end of the line)
> := ______ bind the result of a match to a hypothetical variable

^^^ Quantifier

> ? _______ zero or one
> + _______ one or more
> * _______ zero or more
> ** ______ maximal greedy matching
> ** ______ muliply this (meta)char/subrule times the following digit on right side
> **? _____ minimal matching
> % ______ match this (meta)char/subrule as long as separated by (meta)char/subrule on the right
> %%_____ like %, but allows trailing separator

^^^ Control Chars

These Escape Sequences will be evaluated inside quotes to invisible control chars, if the ":b" aka ":backslash" quoting Adverbs is set (included in :quotewords and :double). They are also usable in regexes and thatswhy also included in the next list.

> \a . . . . . . . . BELL
> \b . . . . . . . . BACKSPACE
> \e . . . . . . . . ESCAPE
> \f . . . . . . . . FORM FEED
> \n . . . . . . . . LINE FEED
> \r . . . . . . . . CARRIAGE RETURN
> \t . . . . . . . . TAB

^^^ Escape Sequences

To be used just inside of regexes (m/.../, s/.../.../ and tr/.../.../ and methods like comb('...')).

> \0[ ... ] . . character given in octal (brackets optional)
> \b . . . . . . word boundary
> \B . . . . . . Match when not on a word boundary
> \c[ ... ] . . named character or control character
> \C[ ... ] . . any character except the bracketed named or control character
> \d. . . . . . digit
> \D. . . . . . nondigit
> \e. . . . . . escape character
> \E. . . . . . anything but an escape character
> \f . . . . . . form feed
> \F. . . . . . anything but a form feed
> \n. . . . . . (logical) newline
> \N. . . . . . anything but a (logical) newline
> \h. . . . . . horizontal whitespace
> \H. . . . . . anything but horizontal whitespace
> \L[ ... ] . . Everything within the brackets is lowercase
> \Q[ ... ]. . all metacharacters within the brackets match as literal characters
> \r . . . . . . return
> \R. . . . . . anything but a return
> \s. . . . . . any whitespace character
> \S. . . . . . anything but whitespace
> \t . . . . . . a tab
> \T. . . . . . anything but a tab
> \U[ ... ] . . Everything within the brackets is uppercase
> \v. . . . . . vertical whitespace
> \V. . . . . . anything but vertical whitespace
> \w. . . . . . word character (Unicode alphanumeric plus "_")
> \W . . . . . anything but a word character
> \x[ ... ] . . character given in hexadecimal (brackets optional)
> \X[ ... ] . . anything but the character given in hexadecimal (brackets optional)

^^^ Subrules

predefined rules (see "routine type"{link: Routine Types} rule) for any grammar or regex. They can have prefixes: *.* (dot) marks a non-capturing subrule, *?* and *!* are also non-capturing positive and negative zero width assertions,

> <alpha> . . . . . . . single alphabetic character
> <upper> . . . . . . . uppercase char
> <lower> . . . . . . . lowercase char
> <digit>. . . . . . . . single digit
> <xdigit> . . . . . . . hexadecimal digit
> <alnum>. . . . . . . alphanumeric char, equivalent to <+alpha +digit>
> <punct> . . . . . . . punctuation char
> <ident> . . . . . . . an identifier
> <print>. . . . . . . . printable char
> <graph> . . . . . . . "graphical" char like kanji
> <cntrl>. . . . . . . . control char, e.g. newline and backspace
> <blank> . . . . . . . mostly a space or tab
> <space> . . . . . . . whitespace character aka \s
> <ws> . . . . . . . . . whitespace, roughly equals \s*
> <wb> . . . . . . . . . zero-width word boundary, spot with between \w and \W
> <ww>. . . . . . . . . zero-width inside word spot between \w and \w
> <?before pattern>. zero-width lookahead
> <!before pattern>. negative zero-width lookahead, true if the pattern does not match
> <?after pattern>. . zero-width lookbehind
> <!after pattern> . . negative zero-width lookbehind
> <?same>. . . . . . . zero-width between two identical chars
> <prior>. . . . . . . . last matched pattern
> <?> . . . . . . . . . . matches nothing, always true
> <!> . . . . . . . . . . always false

^^ Flow Control

^^^ Closure Traits

aka phasers. Every block can contain special named blocks (some are only for loops) that are started at certain times. They are traits (compile time property) of a block object. Those marked with a * can also be used within an expression as in "BEGIN my $x = 3 * 3;".

> BEGIN {...}*. . . at compile time, ASAP, only ever runs once
> CHECK {...}* . . at compile time, ALAP, only ever runs once
> .
> INIT {...}*. . . . at run time, ASAP, only ever runs once
> END {...}. . . . . at run time, ALAP, only ever runs once
> .
> START {...}* . . on first ever execution, once per closure clone
> ENTER {...}* . . at every block entry time, repeats on loop blocks.
> LEAVE {...} . . . at every block exit time
> KEEP {...} . . . . at every successful block exit, part of LEAVE queue
> UNDO {...}. . . . at every unsuccessful block exit, part of LEAVE queue
> .
> FIRST {...}*. . . at loop initialization time, before any ENTER
> NEXT {...} . . . . at loop continuation time, before any LEAVE
> LAST {...} . . . . at loop termination time, after any LEAVE
> .
> PRE {...} . . . . . assert precondition at every block entry, before ENTER
> POST {...} . . . . assert postcondition at every block exit, after LEAVE
> .
> CATCH {...} . . . catch exceptions, before LEAVE
> CONTROL {...}. . catch control exceptions (like next/last/return etc), before LEAVE

^^^ Jump Commands

> goto . . . . jump to a named label
> redo . . . . repeat this loop turn
> next . . . . skip to the next loop turn
> last. . . . . leave this loop now
> break. . . . leave this when clause
> leave. . . . leave this block with a return value
> return . . . leave this routine with a return value

^^^ Conditionals

> if . . . . . . when following expression evals in boolean context to "Bool::True", the block that following after that will be executed
> elsif . . . . works like if, but only recognized if no preceding "if" or "elsif" clause was executed
> else . . . . following block will be executed, when no preceding "if" or "elsif" clause was executed
> unless. . . opposite of if, no "elsif" or "else" is allowed to follow
> given . . . evals an expression into scalar context assignes it to $_ for the following block
> when . . . smartmatches an expression against $_; if the result is "Bool::True", the following block will be executed
> default . . following block will be executed, when no "when" clause was executed

^^^ Loops

> loop . . . . general (endless) loop, unless used as an C-style-loop, evals following expression into void context
> repeat. . . initial command for while or until loops that have their condtion at the end
> while. . . . loop with negative exit condition (exit when false), condition, evals expression into boolean context
> until . . . . loop with positive exit condition(exit when true), evals expression into boolean context
> for . . . . . evals expression into lazy list context and iterates over that list from first to last value, sets each time $_ (can be combined with when as well),

^^^ Routines

routine definition: {{[}} "scope"{link: scopes} {{] [modifier] type [name] [trait] (signature)}} { block }

^^^^ Routine Types

> sub. . . . . . . . normal routine, named block with parmeters
> method . . . . . inheritable object methods
> submethod. . . not inheritable methods
> regex . . . . . . routine that executes a regular expression
> rule. . . . . . . . alias to regex :ratchet :sigspace
> token . . . . . . alias to regex :ratchet
> macro . . . . . . routine that is executed at BEGIN (ASAP, compile time) and returns an AST

^^^^ Routine Modifier

> multi. . . . . marks routines, witch can have siblings with same name but different signature; when called, the one with matching sig is executed
> only . . . . . routines which dont' allow to have an multi sibling (is default, you may leave it out)
> proto . . . . fallback for multi, if no multi signature matches the caller, a proto with same name is executed

^^^^ Routine Traits

"phasers"{link: Closure Traits} (closure traits) can also be seen as routine traits

> export . . . . this routine will be exported my the current module by default
> will do . . . . block of code executed when the subroutine is called. Normally declared implicitly, by providing a block after the subroutine's signature definition
> signature . . signature of a subroutine. Normally declared implicitly, by providing a parameter list and/or return type
> as . . . . . . . inner type constraint that a routine imposes on its return value
> of . . . . . . . official return type of the routine
> cached. . . . marks a subroutine as being memoized
> rw. . . . . . . marks a subroutine as returning an lvalue
> parsed . . . . macro is parsed once, is hygienic, only parsed can be used
> reparsed. . . macro parsed twice, not hygienic, later parsed can be used
> tighter . . . . specifies the precedence of an operator higher than an existing operator "as seen here"{link: table_of_precedence}
> looser. . . . . specifies the precedence of an operator lower than an existing operator "as seen here"{link: table_of_precedence}
> equiv . . . . . specifies the precedence of an operator same as an existing operator "as seen here"{link: table_of_precedence}
> assoc. . . . . specifies the associativity of an operator explicitly "as seen here"{link: Operator Associativity}

^^^^ Parameter Traits

> as . . . . . . . data coming through that parameter will be coerced to the type following *as*
> readonly . . . immutable parameter
> rw . . . . . . . mutable parameter (rw stands for: read write)
> copy. . . . . . read-writable copy of the original argument ("pass-by-value")
> dynamic . . . parameter is an "environmental" variable, a lexical in the dynamic scope
> parcel. . . . . raw reference, will not be contextualized

----

"Overview"[Perl 6 Tablets] - _Chapter:_ "0:History"[Perl 6 History Tablet], "1:Design"[Perl 6 Language Design Tablet], "2:Basics"[Perl 6 Basics Tablet], "3:Var"[Perl 6 Variable Tablet], "4:Op"[Perl 6 Operator Tablet], "5:IO"[Perl 6 IO Tablet], "6:{}"[Perl 6 Block Tablet], "7:Sub"[Perl 6 Subroutine Tablet], "8:OOP"[Perl 6 OOP Tablet], "9:Rx"[Perl 6 Regex Tablet], "10:Meta"[Perl 6 Meta Tablet]
"Intro"[Perl 6 Intro Tablet] - _Appendices:_ "A:Index"[Perl 6 Index Tablet], *"B:Tables"[Perl 6 Lookup Tablet]*, "C:Cook"[Perl 6 Cookbook Tablet], "D:Delta"[Perl 6 Delta Tablet], "E:Best of"[Best Of Perl 6 Tablet], "F:Links"[Perl 6 Links Tablet]

----


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