class Map
Immutable mapping from strings to values
does Associative is Iterable
A Map is an immutable mapping from string keys to values of arbitrary types. It serves as a base class for Hash, which is mutable.
In list context a Map behaves as a list of Pair objects.
Note that the order in which keys, values and pairs are retrieved is generally arbitrary, but the keys
, values
and pairs
methods return them always in the same order when called on the same object.
my := Map.new('a', 1, 'b', 2);say .keys; # can print "a b\n" or "b a\n";say .values; # prints "1 2\n" if the previous line# printed "a b\n", "b a\n" otherwise
Methods
method new
Defined as:
method new(*)
Creates a new Map from a list of alternating keys and values, with the same semantics as described for hash assigning in the Hash documentation, except, for literal pair handling. To ensure pairs correctly get passed, add extra parentheses around all the arguments.
my = Map.new('a', 1, 'b', 2);# WRONG: :b(2) interpreted as named argumentsay Map.new('a', 1, :b(2) ).keys; # OUTPUT: «(a)»# RIGHT: :b(2) interpreted as part of Map's contentssay Map.new( ('a', 1, :b(2)) ).keys; # OUTPUT: «(a b)»
method elems
Defined as:
method elems(Map: --> Int)
Returns the number of pairs stored in the Map.
my = Map.new('a', 1, 'b', 2);say .elems; # OUTPUT: «2»
method ACCEPTS
Defined as:
multi method ACCEPTS(Map: Positional )multi method ACCEPTS(Map: Cool )multi method ACCEPTS(Map: Regex )multi method ACCEPTS(Map: Any )
Used in smart-matching if the right-hand side is an Map
.
If the topic is list-like (Positional), returns True if any of the list elements exist as a key in the Map.
If the topic is of type Cool
(strings, integers etc.), returns True if the topic exists as a key.
If the topic is a regex, returns True if any of the keys match the regex.
As a fallback, the topic is coerced to a list, and the Positional
behavior is applied.
To retrieve a value from the Map by key, use the { }
postcircumfix operator:
my = Map.new('a', 1, 'b', 2);say ; # OUTPUT: «1»
To check whether a given key is stored in a Map, modify the access with the :exists
adverb:
my = Map.new('a', 1, 'b', 2);my = 'a';if :exists
method gist
Defined as:
method gist(Map: --> Str)
Returns the string containing the "gist" of the Map, sorts the pairs and lists up to the first 100, appending an ellipsis if the Map has more than 100 pairs.
method keys
Defined as:
method keys(Map: --> Seq)
Returns a Seq
of all keys in the Map.
my = Map.new('a' => (2, 3), 'b' => 17);say .keys; # OUTPUT: «(a b)»
method values
Defined as:
method values(Map: --> Seq)
Returns a Seq
of all values in the Map.
my = Map.new('a' => (2, 3), 'b' => 17);say .values; # OUTPUT: «((2 3) 17)»
method pairs
Defined as:
method pairs(Map: --> Seq)
Returns a Seq
of all pairs in the Map.
my = Map.new('a' => (2, 3), 'b' => 17);say .pairs; # OUTPUT: «(a => (2 3) b => 17)»
method antipairs
Defined as:
method antipairs(Map: --> Seq)
Returns all keys and their respective values as a Seq of Pair
s where the keys and values have been exchanged, i.e. the opposite of method pairs. Unlike the invert method, there is no attempt to expand list values into multiple pairs.
my = Map.new('a' => (2, 3), 'b' => 17);say .antipairs; # OUTPUT: «((2 3) => a 17 => b)»
method invert
Defined as:
method invert(Map: --> Seq)
Returns all keys and their respective values as a Seq of Pair
s where the keys and values have been exchanged. The difference between invert
and antipairs is that invert
expands list values into multiple pairs.
my = Map.new('a' => (2, 3), 'b' => 17);say .invert; # OUTPUT: «(2 => a 3 => a 17 => b)»
method kv
Defined as:
method kv(Map: --> Seq)
Returns a Seq
of keys and values interleaved.
Map.new('a', 1, 'b', 2).kv # (a 1 b 2)
method Int
Defined as:
method Int(Map: --> Int)
Returns the number of pairs stored in the Map
(same as .elems
).
my = Map.new('a' => 2, 'b' => 17);say .Int; # OUTPUT: «2»
method Numeric
Defined as:
method Numeric(Map: --> Int)
Returns the number of pairs stored in the Map
(same as .elems
).
my = Map.new('a' => 2, 'b' => 17);say .Numeric; # OUTPUT: «2»
method Bool
Defined as:
method Bool(Map: --> Bool)
Returns True
if the invocant contains at least one key/value pair.
my = Map.new('a' => 2, 'b' => 17);say .Bool; # OUTPUT: «True»
method Capture
Defined as:
method Capture(Map: --> Capture)
Returns a Capture where each key, if any, has been converted to a named argument with the same value as it had in the original Map
. The returned Capture
will not contain any positional arguments.
my = Map.new('a' => 2, 'b' => 17);my = .Capture;my-sub(|); # RESULT: «2, 17»sub my-sub(:, :)
Type Graph
Map
Stand-alone image: vector
Routines supplied by role Iterable
Map does role Iterable, which provides the following methods:
(Iterable) method iterator
Defined as:
method iterator(--> Iterator)
Method stub that ensures all classes doing the Iterable
role have a method iterator
.
It is supposed to return an Iterator.
say (1..10).iterator;
(Iterable) method flat
Defined as:
method flat(--> Iterable)
Returns another Iterable that flattens out all iterables that the first one returns.
For example
say (<a b>, 'c').elems; # OUTPUT: «2»say (<a b>, 'c').flat.elems; # OUTPUT: «3»
because <a b>
is a List and thus iterable, so (<a b>, 'c').flat
returns ('a', 'b', 'c')
, which has three elems.
Note that the flattening is recursive, so ((("a", "b"), "c"), "d").flat
returns ("a", "b", "c", "d")
, but it does not flatten itemized sublists:
say ($('a', 'b'), 'c').perl; # OUTPUT: «($("a", "b"), "c")»
(Iterable) method lazy
Defined as:
method lazy(--> Iterable)
Returns a lazy iterable wrapping the invocant.
say (1 ... 1000).is-lazy; # OUTPUT: «False»say (1 ... 1000).lazy.is-lazy; # OUTPUT: «True»
(Iterable) method hyper
Defined as:
method hyper(Int(Cool) : = 64, Int(Cool) : = 4 --> Iterable)
Returns another Iterable that is potentially iterated in parallel, with a given batch size and degree of parallelism.
The order of elements is preserved.
say ([1..100].hyper.map().list);
Use hyper
in situations where it is OK to do the processing of items in parallel, and the output order should be kept relative to the input order. See race
for situations where items are processed in parallel and the output order does not matter.
Options degree and batch
The degree
option (short for "degree of parallelism") configures how many parallel workers should be started. To start 4 workers (e.g. to use at most 4 cores), pass :4degree
to the hyper
or race
method. Note that in some cases, choosing a degree higher than the available CPU cores can make sense, for example I/O bound work or latency-heavy tasks like web crawling. For CPU-bound work, however, it makes no sense to pick a number higher than the CPU core count.
The batch
size option configures the number of items sent to a given parallel worker at once. It allows for making a throughput/latency trade-off. If, for example, an operation is long-running per item, and you need the first results as soon as possible, set it to 1. That means every parallel worker gets 1 item to process at a time, and reports the result as soon as possible. In consequence, the overhead for inter-thread communication is maximized. In the other extreme, if you have 1000 items to process and 10 workers, and you give every worker a batch of 100 items, you will incur minimal overhead for dispatching the items, but you will only get the first results when 100 items are processed by the fastest worker (or, for hyper
, when the worker getting the first batch returns.) Also, if not all items take the same amount of time to process, you might run into the situation where some workers are already done and sit around without being able to help with the remaining work. In situations where not all items take the same time to process, and you don't want too much inter-thread communication overhead, picking a number somewhere in the middle makes sense. Your aim might be to keep all workers about evenly busy to make best use of the resources available.
Blog post on the semantics of hyper and race
(Iterable) method race
Defined as:
method race(Int(Cool) : = 64, Int(Cool) : = 4 --> Iterable)
Returns another Iterable that is potentially iterated in parallel, with a given batch size and degree of parallelism (number of parallel workers).
Unlike hyper
, race
does not preserve the order of elements.
say ([1..100].race.map().list);
Use race in situations where it is OK to do the processing of items in parallel, and the output order does not matter. See hyper
for situations where you want items processed in parallel and the output order should be kept relative to the input order.
Blog post on the semantics of hyper and race
See hyper
for an explanation of :$batch and :$degree.
Routines supplied by class Cool
Map inherits from class Cool, which provides the following methods:
(Cool) routine abs
Defined as:
sub abs(Numeric() )method abs()
Coerces the invocant (or in the sub form, the argument) to Numeric and returns the absolute value (that is, a non-negative number).
say (-2).abs; # OUTPUT: «2»say abs "6+8i"; # OUTPUT: «10»
(Cool) method conj
Defined as:
method conj()
Coerces the invocant to Numeric and returns the complex conjugate (that is, the number with the sign of the imaginary part negated).
say (1+2i).conj; # OUTPUT: «1-2i»
(Cool) routine sqrt
Defined as:
sub sqrt(Numeric(Cool) )method sqrt()
Coerces the invocant to Numeric (or in the sub form, the argument) and returns the square root, that is, a non-negative number that, when multiplied with itself, produces the original number.
say 4.sqrt; # OUTPUT: «2»say sqrt(2); # OUTPUT: «1.4142135623731»
(Cool) method sign
Defined as:
method sign()
Coerces the invocant to Numeric and returns its sign, that is, 0 if the number is 0, 1 for positive and -1 for negative values.
say 6.sign; # OUTPUT: «1»say (-6).sign; # OUTPUT: «-1»say "0".sign; # OUTPUT: «0»
(Cool) method rand
Defined as:
method rand()
Coerces the invocant to Num and returns a pseudo-random value between zero and the number.
say 1e5.rand; # OUTPUT: «33128.495184283»
(Cool) routine sin
Defined as:
sub sin(Numeric(Cool))method sin()
Coerces the invocant (or in the sub form, the argument) to Numeric, interprets it as radians, returns its sine.
say sin(0); # OUTPUT: «0»say sin(pi/4); # OUTPUT: «0.707106781186547»say sin(pi/2); # OUTPUT: «1»
Note that Perl 6 is no computer algebra system, so sin(pi)
typically does not produce an exact 0, but rather a very small floating-point number.
(Cool) routine asin
Defined as:
sub asin(Numeric(Cool))method asin()
Coerces the invocant (or in the sub form, the argument) to Numeric, and returns its arc-sine in radians.
say 0.1.asin; # OUTPUT: «0.10016742116156»say asin(0.1); # OUTPUT: «0.10016742116156»
(Cool) routine cos
Defined as:
sub cos(Numeric(Cool))method cos()
Coerces the invocant (or in sub form, the argument) to Numeric, interprets it as radians, returns its cosine.
say 0.cos; # OUTPUT: «1»say pi.cos; # OUTPUT: «-1»say cos(pi/2); # OUTPUT: «6.12323399573677e-17»
(Cool) routine acos
Defined as:
sub acos(Numeric(Cool))method acos()
Coerces the invocant (or in sub form, the argument) to Numeric, and returns its arc-cosine in radians.
say 1.acos; # OUTPUT: «0»say acos(-1); # OUTPUT: «3.14159265358979»
(Cool) routine tan
Defined as:
sub tan(Numeric(Cool))method tan()
Coerces the invocant (or in sub form, the argument) to Numeric, interprets it as radians, returns its tangent.
say tan(3); # OUTPUT: «-0.142546543074278»say 3.tan; # OUTPUT: «-0.142546543074278»
(Cool) routine atan
Defined as:
sub atan(Numeric(Cool))method atan()
Coerces the invocant (or in sub form, the argument) to Numeric, and returns its arc-tangent in radians.
say atan(3); # OUTPUT: «1.24904577239825»say 3.atan; # OUTPUT: «1.24904577239825»
(Cool) routine atan2
Defined as:
sub atan2(Numeric() , Numeric() = 1e0)method atan2( = 1e0)
Coerces the arguments (including the invocant in the method form) to Numeric, and returns their two-argument arc-tangent in radians.
say atan2(3); # OUTPUT: «1.24904577239825»say 3.atan2; # OUTPUT: «1.24904577239825»
(Cool) method sec
Defined as:
sub sec(Numeric(Cool))method sec()
Coerces the invocant (or in sub form, its argument) to Numeric, interprets it as radians, returns its secant, that is, the reciprocal of its cosine.
say 45.sec; # OUTPUT: «1.90359440740442»say sec(45); # OUTPUT: «1.90359440740442»
(Cool) routine asec
Defined as:
sub asec(Numeric(Cool))method asec()
Coerces the invocant (or in sub form, its argument) to Numeric, and returns its arc-secant in radians.
say 1.asec; # OUTPUT: «0»say sqrt(2).asec; # OUTPUT: «0.785398163397448»
(Cool) routine cosec
Defined as:
sub cosec(Numeric(Cool))method cosec()
Coerces the invocant (or in sub form, its argument) to Numeric, interprets it as radians, returns its cosecant, that is, the reciprocal of its sine.
say 0.45.cosec; # OUTPUT: «2.29903273150897»say cosec(0.45); # OUTPUT: «2.29903273150897»
(Cool) routine acosec
Defined as:
sub acosec(Numeric(Cool))method acosec()
Coerces the invocant (or in sub form, its argument) to Numeric, and returns its arc-cosecant in radians.
say 45.acosec; # OUTPUT: «0.0222240516182672»say acosec(45) # OUTPUT: «0.0222240516182672»
(Cool) routine cotan
Defined as:
sub cotan(Numeric(Cool))method cotan()
Coerces the invocant (or in sub form, its argument) to Numeric, interprets it as radians, returns its cotangent, that is, the reciprocal of its tangent.
say 45.cotan; # OUTPUT: «0.617369623783555»say cotan(45); # OUTPUT: «0.617369623783555»
(Cool) routine acotan
Defined as:
sub acotan(Numeric(Cool))method acotan()
Coerces the invocant (or in sub form, its argument) to Numeric, and returns its arc-cotangent in radians.
say 45.acotan; # OUTPUT: «0.0222185653267191»say acotan(45) # OUTPUT: «0.0222185653267191»
(Cool) routine sinh
Defined as:
sub sinh(Numeric(Cool))method sinh()
Coerces the invocant (or in method form, its argument) to Numeric, and returns its Sine hyperbolicus.
say 1.sinh; # OUTPUT: «1.1752011936438»say sinh(1); # OUTPUT: «1.1752011936438»
(Cool) routine asinh
Defined as:
sub asinh(Numeric(Cool))method asinh()
Coerces the invocant (or in sub form, its argument) to Numeric, and returns its Inverse Sine hyperbolicus.
say 1.asinh; # OUTPUT: «0.881373587019543»say asinh(1); # OUTPUT: «0.881373587019543»
(Cool) routine cosh
Defined as:
sub cosh(Numeric(Cool))method cosh()
Coerces the invocant (or in sub form, its argument) to Numeric, and returns its Cosine hyperbolicus.
say cosh(0.5); # OUTPUT: «1.12762596520638»
(Cool) routine acosh
Defined as:
sub acosh(Numeric(Cool))method acosh()
Coerces the invocant (or in sub form, its argument) to Numeric, and returns its Inverse Cosine hyperbolicus.
say acosh(45); # OUTPUT: «4.4996861906715»
(Cool) routine tanh
Defined as:
sub tanh(Numeric(Cool))method tanh()
Coerces the invocant (or in sub form, its argument) to Numeric, interprets it as radians and returns its Tangent hyperbolicus.
say tanh(0.5); # OUTPUT: «0.46211715726001»say tanh(atanh(0.5)); # OUTPUT: «0.5»
(Cool) routine atanh
Defined as:
sub atanh(Numeric(Cool))method atanh()
Coerces the invocant (or in sub form, its argument) to Numeric, and returns its Inverse tangent hyperbolicus.
say atanh(0.5); # OUTPUT: «0.549306144334055»
(Cool) routine sech
Defined as:
sub sech(Numeric(Cool))method sech()
Coerces the invocant (or in sub form, its argument) to Numeric, and returns its Secant hyperbolicus.
say 0.sech; # OUTPUT: «1»
(Cool) routine asech
Defined as:
sub asech(Numeric(Cool))method asech()
Coerces the invocant (or in sub form, its argument) to Numeric, and returns its Inverse hyperbolic secant.
say 0.8.asech; # OUTPUT: «0.693147180559945»
(Cool) routine cosech
Defined as:
sub cosech(Numeric(Cool))method cosech()
Coerces the invocant (or in sub form, its argument) to Numeric, and returns its Hyperbolic cosecant.
say cosech(pi/2); # OUTPUT: «0.434537208094696»
(Cool) routine acosech
Defined as:
sub acosech(Numeric(Cool))method acosech()
Coerces the invocant (or in sub form, its argument) to Numeric, and returns its Inverse hyperbolic cosecant.
say acosech(4.5); # OUTPUT: «0.220432720979802»
(Cool) routine cotanh
Defined as:
sub cotanh(Numeric(Cool))method cotanh()
Coerces the invocant (or in sub form, its argument) to Numeric, and returns its Hyperbolic cotangent.
say cotanh(pi); # OUTPUT: «1.00374187319732»
(Cool) routine acotanh
Defined as:
sub acotanh(Numeric(Cool))method acotanh()
Coerces the invocant (or in sub form, its argument) to Numeric, and returns its Inverse hyperbolic cotangent.
say acotanh(2.5); # OUTPUT: «0.423648930193602»
(Cool) routine cis
Defined as:
sub cis(Numeric(Cool))method cis()
Coerces the invocant (or in sub form, its argument) to Numeric, and returns cos(argument) + i*sin(argument).
say cis(pi/4); # OUTPUT: «0.707106781186548+0.707106781186547i»
(Cool) routine log
Defined as:
multi sub log(Numeric(Cool) , Numeric(Cool) ?)multi method log(Cool: Cool ?)
Coerces the arguments (including the invocant in the method form) to Numeric, and returns its Logarithm to base $base
, or to base e
(Euler's Number) if no base was supplied (Natural logarithm). Returns NaN
if $base
is negative. Throws an exception if $base
is 1
.
say (e*e).log; # OUTPUT: «2»
(Cool) routine log10
Defined as:
multi sub log10(Cool(Numeric))multi method log10()
Coerces the invocant (or in the sub form, the invocant) to Numeric, and returns its Logarithm to base 10, that is, a number that approximately produces the original number when raised to the power of 10. Returns NaN
for negative arguments and -Inf
for 0
.
say log10(1001); # OUTPUT: «3.00043407747932»
(Cool) method exp
Defined as:
multi sub exp(Cool , Cool ?)multi method exp(Cool: Cool ?)
Coerces the arguments (including the invocant in the method from) to Numeric, and returns $base
raised to the power of the first number. If no $base
is supplied, e
(Euler's Number) is used.
say 0.exp; # OUTPUT: «1»say 1.exp; # OUTPUT: «2.71828182845905»say 10.exp; # OUTPUT: «22026.4657948067»
(Cool) method unpolar
Defined as:
method unpolar(Numeric(Cool))
Coerces the arguments (including the invocant in the method form) to Numeric, and returns a complex number from the given polar coordinates. The invocant (or the first argument in sub form) is the magnitude while the argument (i.e. the second argument in sub form) is the angle. The angle is assumed to be in radians.
say sqrt(2).unpolar(pi/4); # OUTPUT: «1+1i»
(Cool) routine round
Defined as:
multi sub round(Numeric(Cool))multi method round(Cool: = 1)
Coerces the invocant (or in sub form, its argument) to Numeric, and rounds it to the unit of $unit
. If $unit
is 1, rounds to the nearest integer.
say 1.7.round; # OUTPUT: «2»say 1.07.round(0.1); # OUTPUT: «1.1»say 21.round(10); # OUTPUT: «20»
Always rounds up if the number is at mid-point:
say (−.5 ).round; # OUTPUT: «0»say ( .5 ).round; # OUTPUT: «1»say (−.55).round(.1); # OUTPUT: «-0.5»say ( .55).round(.1); # OUTPUT: «0.6»
(Cool) routine floor
Defined as:
multi sub floor(Numeric(Cool))multi method floor
Coerces the invocant (or in sub form, its argument) to Numeric, and rounds it downwards to the nearest integer.
say "1.99".floor; # OUTPUT: «1»say "-1.9".floor; # OUTPUT: «-2»say 0.floor; # OUTPUT: «0»
(Cool) routine ceiling
Defined as:
multi sub ceiling(Numeric(Cool))multi method ceiling
Coerces the invocant (or in sub form, its argument) to Numeric, and rounds it upwards to the nearest integer.
say "1".ceiling; # OUTPUT: «1»say "-0.9".ceiling; # OUTPUT: «0»say "42.1".ceiling; # OUTPUT: «43»
(Cool) routine truncate
Defined as:
multi sub truncate(Numeric(Cool))multi method truncate()
Coerces the invocant (or in sub form, its argument) to Numeric, and rounds it towards zero.
say 1.2.truncate; # OUTPUT: «1»say truncate -1.2; # OUTPUT: «-1»
(Cool) routine ord
Defined as:
sub ord(Str(Cool))method ord()
Coerces the invocant (or in sub form, its argument) to Str, and returns the Unicode code point number of the first code point.
say 'a'.ord; # OUTPUT: «97»
The inverse operation is chr.
Mnemonic: returns an ordinal number
(Cool) method path
Defined as:
method path()
DEPRECATED. Existed only in the Rakudo implementation and isn't part of any language released. Issues deprecation warnings in 6.d language and will be removed entirely when 6.e language is released.
Stringifies the invocant and converts it to IO::Path object. Use the .IO method
instead.
(Cool) routine chr
Defined as:
sub chr(Int(Cool))method chr()
Coerces the invocant (or in sub form, its argument) to Int, interprets it as a Unicode code points, and returns a string made of that code point.
say '65'.chr; # OUTPUT: «A»
The inverse operation is ord.
Mnemonic: turns an integer into a character.
(Cool) routine chars
Defined as:
sub chars(Str(Cool))method chars()
Coerces the invocant (or in sub form, its argument) to Str, and returns the number of characters in the string. Please note that on the JVM, you currently get codepoints instead of graphemes.
say 'møp'.chars; # OUTPUT: «3»say 'ã̷̠̬̊'.chars; # OUTPUT: «1»say '👨👩👧👦🏿'.chars; # OUTPUT: «1»
Graphemes are user visible characters. That is, this is what the user thinks of as a “character”.
Graphemes can contain more than one codepoint. Typically the number of graphemes and codepoints differs when Prepend
or Extend
characters are involved (also known as Combining characters), but there are many other cases when this may happen. Another example is \c[ZWJ]
(Zero-width joiner).
You can check Grapheme_Cluster_Break
property of a character in order to see how it is going to behave:
say ‘ã̷̠̬̊’.uniprops(‘Grapheme_Cluster_Break’); # OUTPUT: «(Other Extend Extend Extend Extend)»say ‘👨👩👧👦🏿’.uniprops(‘Grapheme_Cluster_Break’); # OUTPUT: «(E_Base_GAZ ZWJ E_Base_GAZ ZWJ E_Base_GAZ ZWJ E_Base_GAZ E_Modifier)»
You can read more about graphemes in the Unicode Standard, which Perl 6 tightly follows.
(Cool) routine codes
Defined as:
sub codes(Str(Cool))method codes()
Coerces the invocant (or in sub form, its argument) to Str, and returns the number of Unicode code points.
say 'møp'.codes; # OUTPUT: «3»
The same result will be obtained with
say +'møp'.ords; # OUTPUT: «3»
ords first obtains the actual codepoints, so there might be a difference in speed.
(Cool) routine flip
Defined as:
sub flip(Str(Cool))method flip()
Coerces the invocant (or in sub form, its argument) to Str, and returns a reversed version.
say 421.flip; # OUTPUT: «124»
(Cool) routine trim
Defined as:
sub trim(Str(Cool))method trim()
Coerces the invocant (or in sub form, its argument) to Str, and returns the string with both leading and trailing whitespace stripped.
my = ' abc '.trim;say "<$stripped>"; # OUTPUT: «<abc>»
(Cool) routine trim-leading
Defined as:
sub trim-leading(Str(Cool))method trim-leading()
Coerces the invocant (or in sub form, its argument) to Str, and returns the string with leading whitespace stripped.
my = ' abc '.trim-leading;say "<$stripped>"; # OUTPUT: «<abc >»
(Cool) routine trim-trailing
Defined as:
sub trim-trailing(Str(Cool))method trim-trailing()
Coerces the invocant (or in sub form, its argument) to Str, and returns the string with trailing whitespace stripped.
my = ' abc '.trim-trailing;say "<$stripped>"; # OUTPUT: «< abc>»
(Cool) routine lc
Defined as:
sub lc(Str(Cool))method lc()
Coerces the invocant (or in sub form, its argument) to Str, and returns it case-folded to lower case.
say "ABC".lc; # OUTPUT: «abc»
(Cool) routine uc
Defined as:
sub uc(Str(Cool))method uc()
Coerces the invocant (or in sub form, its argument) to Str, and returns it case-folded to upper case (capital letters).
say "Abc".uc; # OUTPUT: «ABC»
(Cool) routine fc
Defined as:
sub fc(Str(Cool))method fc()
Coerces the invocant (or in sub form, its argument) to Str, and returns the result a Unicode "case fold" operation suitable for doing caseless string comparisons. (In general, the returned string is unlikely to be useful for any purpose other than comparison.)
say "groß".fc; # OUTPUT: «gross»
(Cool) routine tc
Defined as:
sub tc(Str(Cool))method tc()
Coerces the invocant (or in sub form, its argument) to Str, and returns it with the first letter case-folded to title case (or where not available, upper case).
say "abC".tc; # OUTPUT: «AbC»
(Cool) routine tclc
Defined as:
sub tclc(Str(Cool))method tclc()
Coerces the invocant (or in sub form, its argument) to Str, and returns it with the first letter case-folded to title case (or where not available, upper case), and the rest of the string case-folded to lower case.
say 'abC'.tclc; # OUTPUT: «Abc»
(Cool) routine wordcase
Defined as:
sub wordcase(Str(Cool) , : = , Mu : = True)method wordcase(: = , Mu : = True)
Coerces the invocant (or in sub form, the first argument) to Str, and filters each word that smart-matches against $where
through the &filter
. With the default filter (first character to upper case, rest to lower) and matcher (which accepts everything), this title-cases each word:
say "perl 6 programming".wordcase; # OUTPUT: «Perl 6 Programming»
With a matcher:
say "have fun working on perl".wordcase(:where());# Have fun Working on Perl
With a customer filter too:
say "have fun working on perl".wordcase(:filter(), :where());# HAVE fun WORKING on PERL
(Cool) routine samecase
Defined as:
sub samecase(Cool , Cool )method samecase(Cool: Cool )
Coerces the invocant (or in sub form, the first argument) to Str, and returns a copy of $string
with case information for each individual character changed according to $pattern
. (The pattern string can contain three types of characters, i.e. uppercase, lowercase and caseless. For a given character in $pattern
its case information determines the case of the corresponding character in the result.) If $string
is longer than $pattern
, the case information from the last character of $pattern
is applied to the remaining characters of $string
.
say "perL 6".samecase("A__a__"); # OUTPUT: «Perl 6»say "pERL 6".samecase("Ab"); # OUTPUT: «Perl 6»
(Cool) method uniprop
Defined as:
multi sub uniprop(Str(Cool), |c)multi sub uniprop(Int , Stringy )multi sub uniprop(Str, , Stringy )multi method uniprop(|c)
Interprets the invocant as a Str, and returns the unicode property of the first character. If no property is specified returns the General Category. Returns a Bool for Boolean properties.
say 'a'.uniprop; # OUTPUT: «Ll»say '1'.uniprop; # OUTPUT: «Nd»say 'a'.uniprop('Alphabetic'); # OUTPUT: «True»say '1'.uniprop('Alphabetic'); # OUTPUT: «False»
(Cool) method uniprops
Defined as:
sub uniprops(Str , Stringy = "General_Category")
Interprets the invocant as a Str, and returns the unicode property for each character as a Seq. If no property is specified returns the General Category. Returns a Bool for Boolean properties. Similar to uniprop
(Cool) method uniname
Defined as:
sub uniname(Str(Cool) --> Str)method uniname(--> Str)
Interprets the invocant / first argument as a Str, and returns the Unicode codepoint name of the first codepoint of the first character. See uninames for a routine that works with multiple codepoints, and uniparse for the opposite direction.
# Camelia in Unicodesay ‘»ö«’.uniname;# OUTPUT: «"RIGHT-POINTING DOUBLE ANGLE QUOTATION MARK"»say "Ḍ̇".uniname; # Note, doesn't show "COMBINING DOT ABOVE"# OUTPUT: «"LATIN CAPITAL LETTER D WITH DOT BELOW"»# Find the char with the longest Unicode name.say (0..0x1FFFF).sort(*.uniname.chars)[].chr.uniname;# OUTPUT: ««ARABIC LIGATURE UIGHUR KIRGHIZ YEH WITH HAMZA ABOVE WITH ALEF MAKSURA INITIAL FORM»»
(Cool) method uninames
Defined as:
sub uninames(Str)method uninames()
Returns of a Seq of Unicode names for the all the codepoints in the Str provided.
say ‘»ö«’.uninames.perl;# OUTPUT: «("RIGHT-POINTING DOUBLE ANGLE QUOTATION MARK", "LATIN SMALL LETTER O WITH DIAERESIS", "LEFT-POINTING DOUBLE ANGLE QUOTATION MARK").Seq»
Note this example, which gets a Seq where each element is a Seq of all the codepoints in that character.
say "Ḍ̇'oh".comb>>.uninames.perl;# OUTPUT: «(("LATIN CAPITAL LETTER D WITH DOT BELOW", "COMBINING DOT ABOVE").Seq, ("APOSTROPHE",).Seq, ("LATIN SMALL LETTER O",).Seq, ("LATIN SMALL LETTER H",).Seq)»
See uniparse for the opposite direction.
(Cool) method unimatch
Defined as:
multi sub unimatch(Str , |c)multi unimatch(Int , Stringy , Stringy = )
Checks if the given integer codepoint or the first letter of the string given have a unicode property equal to the value you give. If you supply the Unicode property to be checked it will only return True if that property matches the given value.
say unimatch 'A', 'Latin'; # OUTPUT: «True»say unimatch 'A', 'Latin', 'Script'; # OUTPUT: «True»say unimatch 'A', 'Ll'; # OUTPUT: «True»
(Cool) routine chop
Defined as:
sub chop(Str(Cool))method chop()
Coerces the invocant (or in sub form, its argument) to Str, and returns it with the last character removed.
say 'perl'.chop; # OUTPUT: «per»
(Cool) routine chomp
Defined as:
sub chomp(Str(Cool))method chomp()
Coerces the invocant (or in sub form, its argument) to Str, and returns it with the last character removed, if it is a logical newline.
say 'ab'.chomp.chars; # OUTPUT: «2»say "a\n".chomp.chars; # OUTPUT: «1»
(Cool) routine substr
Defined as:
sub substr(Str(Cool) , |c)method substr(|c)
Coerces the invocant (or in the sub form, the first argument) to Str, and calls Str.substr with the arguments.
(Cool) routine ords
Defined as:
sub ords(Str(Cool) )method ords()
Coerces the invocant (or in the sub form, the first argument) to Str, and returns a list of Unicode codepoints for each character.
say "Camelia".ords; # OUTPUT: «67 97 109 101 108 105 97»say ords 10; # OUTPUT: «49 48»
This is the list-returning version of ord. The inverse operation in chrs. If you are only interested in the number of codepoints, codes is a possibly faster option.
(Cool) routine chrs
Defined as:
sub chrs(* --> Str)method chrs()
Coerces the invocant (or in the sub form, the argument list) to a list of integers, and returns the string created by interpreting each integer as a Unicode codepoint, and joining the characters.
say <67 97 109 101 108 105 97>.chrs; # OUTPUT: «Camelia»
This is the list-input version of chr. The inverse operation is ords.
(Cool) routine split
Defined as:
multi sub split( Str , Str(Cool) , = Inf, :, :, :, :, :)multi sub split(Regex , Str(Cool) , = Inf, :, :, :, :, :)multi sub split(, Str(Cool) , = Inf, :, :, :, :, :)multi method split( Str , = Inf, :, :, :, :, :)multi method split(Regex , = Inf, :, :, :, :, :)multi method split(, = Inf, :, :, :, :, :)
Coerces the invocant (or in the sub form, the second argument) to Str, and splits it into pieces based on delimiters found in the string.
If $delimiter
is a string, it is searched for literally and not treated as a regex. You can also provide multiple delimiters by specifying them as a list; mixing Cool and Regex objects is OK.
say split(';', "a;b;c").perl; # OUTPUT: «("a", "b", "c")»say split(';', "a;b;c", 2).perl; # OUTPUT: «("a", "b;c").Seq»say split(';', "a;b;c,d").perl; # OUTPUT: «("a", "b", "c,d")»say split(/\;/, "a;b;c,d").perl; # OUTPUT: «("a", "b", "c,d")»say split(//, "a;b;c,d").perl; # OUTPUT: «("a", "b", "c", "d")»say split(['a', /b+/, 4], '1a2bb345').perl; # OUTPUT: «("1", "2", "3", "5")»
By default, split omits the matches, and returns a list of only those parts of the string that did not match. Specifying one of the :k, :v, :kv, :p
adverbs changes that. Think of the matches as a list that is interleaved with the non-matching parts.
The :v
interleaves the values of that list, which will be either Match objects, if a Regex was used as a matcher in the split, or Str objects, if a Cool was used as matcher. If multiple delimiters are specified, Match objects will be generated for all of them, unless all of the delimiters are Cool.
say 'abc'.split(/b/, :v); # OUTPUT: «(a 「b」 c)»say 'abc'.split('b', :v); # OUTPUT: «(a b c)»
:k
interleaves the keys, that is, the indexes:
say 'abc'.split(/b/, :k); # OUTPUT: «(a 0 c)»
:kv
adds both indexes and matches:
say 'abc'.split(/b/, :kv); # OUTPUT: «(a 0 「b」 c)»
and :p
adds them as Pairs, using the same types for values as :v
does:
say 'abc'.split(/b/, :p); # OUTPUT: «(a 0 => 「b」 c)»say 'abc'.split('b', :p); # OUTPUT: «(a 0 => b c)»
You can only use one of the :k, :v, :kv, :p
adverbs in a single call to split
.
Note that empty chunks are not removed from the result list. For that behavior, use the `:skip-empty` named argument:
say ("f,,b,c,d".split: /","/ ).perl; # OUTPUT: «("f", "", "b", "c", "d")»say ("f,,b,c,d".split: /","/, :skip-empty).perl; # OUTPUT: «("f", "b", "c", "d")»
See also: comb.
(Cool) routine lines
Defined as:
sub lines(Str(Cool))method lines()
Coerces the invocant (and in sub form, the argument) to Str, decomposes it into lines (with the newline characters stripped), and returns the list of lines.
say lines("a\nb\n").join('|'); # OUTPUT: «a|b»say "some\nmore\nlines".lines.elems; # OUTPUT: «3»
This method can be used as part of an IO::Path
to process a file line-by-line, since IO::Path
objects inherit from Cool
, e.g.:
for 'huge-csv'.IO.lines -># or if you'll be processing latermy = 'huge-csv'.IO.lines;
Without any arguments, sub lines
operates on $*ARGFILES
, which defaults to $*IN
in the absence of any filenames.
To modify values in place use is copy
to force a writable container.
for .lines -> is copy
(Cool) method words
Defined as:
method words(Int() )
Coerces the invocant to Str, and returns a list of words that make up the string (and if $limit
is supplied, only the first $limit
words).
say 'The quick brown fox'.words.join('|'); # OUTPUT: «The|quick|brown|fox»say 'The quick brown fox'.words(2).join('|'); # OUTPUT: «The|quick»
Only whitespace counts as word boundaries
say "isn't, can't".words.join('|'); # OUTPUT: «isn't,|can't»
(Cool) routine comb
Defined as:
multi sub comb(Regex , Str(Cool) , = * --> Seq)multi method comb(Regex , = * --> Seq)
Returns all (or if supplied, at most $limit
) matches of the invocant (method form) or the second argument (sub form) against the Regex as a list of strings.
say "6 or 12".comb(/\d+/).join(", "); # OUTPUT: «6, 12»
(Cool) method contains
multi method contains(Cool: Str(Cool) , Cool ? --> Bool)
Coerces the invocant and first argument to Str, and searches for $needle
in the string starting from $start
. Returns True
if $needle
is found.
say "Hello, World".contains('Hello'); # OUTPUT: «True»say "Hello, World".contains('hello'); # OUTPUT: «False»say "Hello, World".contains(','); # OUTPUT: «True»say "Hello, World".contains(',', 3); # OUTPUT: «True»say "Hello, World".contains(',', 10); # OUTPUT: «False»
Note that because of how a List or Array is coerced into a Str, the results may sometimes be surprising. See traps.
(Cool) routine index
Defined as:
multi sub index(Str(Cool) , Str , Int(Cool) = 0 --> Int)multi method index(Str(Cool) , Int(Cool) = 0 --> Int)
Coerces the first two arguments (in method form, also counting the invocant) to Str, and searches for $needle
in the string starting from $startpos
. It returns the offset into the string where $needle
was found, and an undefined value if it was not found.
See the documentation in type Str for examples.
(Cool) routine rindex
Defined as:
multi sub rindex(Str(Cool) , Str(Cool) , Int(Cool) = .chars)multi method rindex(Str(Cool) : Str(Cool) , Int(Cool) = .chars)
Coerces the first two arguments (including the invocant in method form) to Str and $startpos
to Int, and returns the last position of $needle
in $haystack
not after $startpos
. Returns an undefined value if $needle
wasn't found.
See the documentation in type Str for examples.
(Cool) routine match
Defined as:
multi method match(Cool: , *)
Coerces the invocant to Str and calls the method match on it.
(Cool) method fmt
Defined as:
method fmt( = '%s' --> Str)
Uses $format
to return a formatted representation of the invocant.
For more information about formats strings, see sprintf.
say 11.fmt('This Int equals %03d'); # OUTPUT: «This Int equals 011»say '16'.fmt('Hexadecimal %x'); # OUTPUT: «Hexadecimal 10»
(Cool) routine roots
Defined as:
multi sub roots(Numeric(Cool) , Int(Cool) )multi method roots(Int(Cool) )
Coerces the first argument (and in method form, the invocant) to Numeric and the second ($n
) to Int, and produces a list of $n
Complex $n
-roots, which means numbers that, raised to the $n
th power, approximately produce the original number.
For example
my = 16;my = .roots(4);say ;for -># OUTPUT:«2+0i 1.22464679914735e-16+2i -2+2.44929359829471e-16i -3.67394039744206e-16-2i»# OUTPUT:«1.77635683940025e-15»# OUTPUT:«4.30267170434156e-15»# OUTPUT:«8.03651692704705e-15»# OUTPUT:«1.04441561648202e-14»
(Cool) method IO
Defined as:
method IO(--> IO::Path)
Coerces the invocant to IO::Path.
.say for '.'.IO.dir; # gives a directory listing
(Cool) routine EVAL
Defined as:
method EVAL(*)
sub EVAL( where Cool|Blob, : = 'perl6')
Method form calls subroutine form with invocant as $code
, passing along named args, if any. Subroutine form coerces Cool $code
to Str. If $code
is a Blob, it'll be processed using the same encoding as the $lang
compiler would: for perl6
, uses the encoding specified via --encoding
command line argument, or utf-8
if none were given; for Perl5
, processes using same rules as perl
.
This works as-is with a literal string parameter. More complex input, such as a variable or string with embedded code, is illegal by default. This can be overridden in any of several ways:
use MONKEY-SEE-NO-EVAL;use MONKEY; # shortcut that turns on all MONKEY pragmasuse Test;# any of the above allows:EVAL "say "; # OUTPUT: «10»
Symbols in the current lexical scope are visible to code in an EVAL
.
my = 42;EVAL 'say $answer;'; # OUTPUT: «42»
However, since the set of symbols in a lexical scope is immutable after compile time, an EVAL can never introduce symbols into the surrounding scope.
EVAL 'my $lives = 9'; say ; # error, $lives not declared
Furthermore, the EVAL
is evaluated in the current package:
say ::answer; # OUTPUT: «42»
And also the current language, meaning any added syntax is available:
sub infix:<mean>(*) is assoc<list>EVAL 'say 2 mean 6 mean 4'; # OUTPUT: «4»
An EVAL
statement evaluates to the result of the last statement:
sub infix:<mean>(*) is assoc<list>say EVAL 'say 1; 2 mean 6 mean 4'; # OUTPUT: «14»
EVAL
is also a gateway for executing code in other languages:
EVAL "use v5.20; say 'Hello from perl5!'", :lang<Perl5>;
(Cool) routine EVALFILE
Defined as:
sub EVALFILE( where Blob|Cool, : = 'perl6')
Slurps the specified file and evaluates it. Behaves the same way as EVAL
with regard to Blob decoding, scoping, and the $lang
parameter. Evaluates to the value produced by the final statement in the file.
EVALFILE "foo.p6";
Routines supplied by class Any
Map inherits from class Any, which provides the following methods:
(Any) method ACCEPTS
Defined as:
multi method ACCEPTS(Any: Mu )
Usage:
EXPR.ACCEPTS(EXPR);
Returns True
if $other === self
(i.e. it checks object identity).
Many built-in types override this for more specific comparisons
(Any) method any
Defined as:
method any(--> Junction)
Interprets the invocant as a list and creates an any-Junction from it.
say so 2 == <1 2 3>.any; # OUTPUT: «True»say so 5 == <1 2 3>.any; # OUTPUT: «False»
(Any) method all
Defined as:
method all(--> Junction)
Interprets the invocant as a list and creates an all-Junction from it.
say so 1 < <2 3 4>.all; # OUTPUT: «True»say so 3 < <2 3 4>.all; # OUTPUT: «False»
(Any) method one
Defined as:
method one(--> Junction)
Interprets the invocant as a list and creates a one-Junction from it.
say so 1 == (1, 2, 3).one; # OUTPUT: «True»say so 1 == (1, 2, 1).one; # OUTPUT: «False»
(Any) method none
Defined as:
method none(--> Junction)
Interprets the invocant as a list and creates a none-Junction from it.
say so 1 == (1, 2, 3).none; # OUTPUT: «False»say so 4 == (1, 2, 3).none; # OUTPUT: «True»
(Any) method list
Defined as:
multi method list(Any: -->List)multi method list(Any \SELF: -->List)
Applies the infix ,
operator to the invocant and returns the resulting List:
say 42.list.^name; # OUTPUT: «List»say 42.list.elems; # OUTPUT: «1»
(Any) method push
Defined as:
method push(|values --> Positional)
The method push is defined for undefined invocants and allows for autovivifying undefined to an empty Array, unless the undefined value implements Positional already. The argument provided will then be pushed into the newly created Array.
my ;say <a>; # OUTPUT: «(Any)» <-- Undefined<a>.push(1); # .push on Anysay ; # OUTPUT: «{a => [1]}» <-- Note the Array
(Any) routine reverse
Defined as:
multi sub reverse(* --> Seq)multi method reverse(List: --> Seq)
Returns a Seq with the same elements in reverse order.
Note that reverse
always refers to reversing elements of a list; to reverse the characters in a string, use flip.
Examples:
say <hello world!>.reverse; # OUTPUT: «(world! hello)»say reverse ^10; # OUTPUT: «(9 8 7 6 5 4 3 2 1 0)»
(Any) method sort
Defined as:
multi method sort()multi method sort()
Sorts iterables with cmp or given code object and returns a new Seq. Optionally, takes a Callable as a positional parameter, specifying how to sort.
Examples:
say <b c a>.sort; # OUTPUT: «(a b c)»say 'bca'.comb.sort.join; # OUTPUT: «abc»say 'bca'.comb.sort().join; # OUTPUT: «cba»say '231'.comb.sort(:«<=>»).join; # OUTPUT: «123»
(Any) method map
Defined as:
multi method map(\SELF: ;; :, :)
map
will iterate over the invocant and apply the number of positional parameters of the code object from the invocant per call. The returned values of the code object will become elements of the returned Seq.
The :$label
and :$item
are useful only internally, since for
loops get converted to map
s. The :$label
takes an existing Label to label the .map
's loop with and :$item
controls whether the iteration will occur over (SELF,)
(if :$item
is set) or SELF
.
(Any) method deepmap
Defined as:
method deepmap( --> List) is nodal
deepmap
will apply &block
to each element and return a new List with the return values of &block
, unless the element does the Iterable role. For those elements deepmap will descend recursively into the sublist.
say [[1,2,3],[[4,5],6,7]].deepmap(* + 1);# OUTPUT: «[[2 3 4] [[5 6] 7 8]]»
(Any) method duckmap
Defined as:
method duckmap() is rw is nodal
duckmap
will apply &block
on each element and return a new list with defined return values of the block. For undefined return values, duckmap will try to descend into the element if that element implements Iterable.
<a b c d e f g>.duckmap(-> where <c d e>.any ).say;# OUTPUT: «(a b C D E f g)»(('d', 'e'), 'f').duckmap(-> where <e f>.any ).say;# OUTPUT: «((d E) F)»
(Any) method nodemap
Defined as:
method nodemap( --> List) is nodal
nodemap
will apply &block
to each element and return a new List with the return values of &block
. In contrast to deepmap it will not descend recursively into sublists if it finds elements which does the Iterable role.
say [[1,2,3], [[4,5],6,7], 7].nodemap(*+1);# OUTPUT: «(4, 4, 8)»say [[2, 3], [4, [5, 6]]]».nodemap(*+1)# OUTPUT: «((3 4) (5 3))»
The examples above would have produced the exact same results if we had used map instead of nodemap
. The difference between the two lies in the fact that map flattens out slips while nodemap
doesn't.
say [[2,3], [[4,5],6,7], 7].nodemap();# OUTPUT: «(() () 7)»say [[2,3], [[4,5],6,7], 7].map();# OUTPUT: «(7)»
(Any) method flat
Defined as:
method flat(--> Seq) is nodal
Interprets the invocant as a list, flattens non-containerized Iterables into a flat list, and returns that list. Keep in mind Map and Hash types are Iterable and so will be flattened into lists of pairs.
say ((1, 2), (3), %(:42a)); # OUTPUT: «((1 2) 3 {a => 42})»say ((1, 2), (3), %(:42a)).flat; # OUTPUT: «(1 2 3 a => 42)»
Note that Arrays containerize their elements by default, and so flat
will not flatten them. You can use hyper method call to call .List
method on all the inner Iterables and so de-containerize them, so that flat
can flatten them:
say [[1, 2, 3], [(4, 5), 6, 7]] .flat; # OUTPUT: «([1 2 3] [(4 5) 6 7])»say [[1, 2, 3], [(4, 5), 6, 7]]».List.flat; # OUTPUT: «(1 2 3 4 5 6 7)»
For more fine-tuned options, see deepmap, duckmap, and signature destructuring
(Any) method eager
Defined as:
method eager(--> Seq) is nodal
Interprets the invocant as a List, evaluates it eagerly, and returns that List.
my = 1..5;say ; # OUTPUT: «1..5»say .eager; # OUTPUT: «(1 2 3 4 5)»
(Any) method elems
Defined as:
method elems(--> Int) is nodal
Interprets the invocant as a list, and returns the number of elements in the list.
say 42.elems; # OUTPUT: «1»say <a b c>.elems; # OUTPUT: «3»
(Any) method end
method end(--> Any) is nodal
Interprets the invocant as a list, and returns the last index of that list.
say 6.end; # OUTPUT: «0»say <a b c>.end; # OUTPUT: «2»
(Any) method pairup
Defined as:
method pairup(--> Seq) is nodal
Interprets the invocant as a list, and constructs a list of pairs from it, in the same way that assignment to a Hash does. That is, it takes two consecutive elements and constructs a pair from them, unless the item in the key position already is a pair (in which case the pair is passed through, and the next list item, if any, is considered to be a key again).
say (a => 1, 'b', 'c').pairup.perl; # OUTPUT: «(:a(1), :b("c")).Seq»
(Any) sub exit
Defined as:
sub exit(Int() = 0)
Exits the current process with return code $status
or zero if no value has been specified. The exit value ($status
), when different from zero, has to be opportunely evaluated from the process that catches it (e.g., a shell).
exit
does prevent the LEAVE phaser to be executed.
exit
should be used as last resort only to signal the parent process about an exit code different from zero, and should not be used to terminate exceptionally a method or a sub: use exceptions instead.
It is worth noting that the only way to return an exit code different from zero from a Main function is by means of using exit
.
(Any) sub item
Defined as:
proto sub item(|) is puremulti item(\x)multi item(|c)multi item(Mu )
Forces given object to be evaluated in item context and returns the value of it.
say item([1,2,3]).perl; # OUTPUT: «$[1, 2, 3]»say item( %( apple => 10 ) ).perl; # OUTPUT: «${:apple(10)}»say item("abc").perl; # OUTPUT: «"abc"»
You can also use $
as item contextualizer.
say $[1,2,3].perl; # OUTPUT: «$[1, 2, 3]»say $("abc").perl; # OUTPUT: «"abc"»
(Any) method Array
Defined as:
method Array(--> Array) is nodal
Coerce the invocant to Array.
(Any) method List
Defined as:
method List(--> List) is nodal
Coerce the invocant to List, using the list method.
(Any) method Hash
Defined as:
proto method Hash(|) is nodalmulti method Hash( --> Hash)
Coerce the invocant to Hash by invoking the method hash
on it.
(Any) method hash
Defined as:
proto method hash(|) is nodalmulti method hash(Any: --> Hash)multi method hash(Any: --> Hash)
Creates a new Hash, empty in the case the invocant is undefined, or coerces the invocant to an Hash
in the case it is defined.
my ; # $d is Anysay .hash; # OUTPUT: {}.append: 'a', 'b';say .hash; # OUTPUT: {a => b}
(Any) method Slip
Defined as:
method Slip(--> Slip) is nodal
Coerce the invocant to Slip.
(Any) method Map
Defined as:
method Map(--> Map) is nodal
Coerce the invocant to Map.
(Any) method Bag
Defined as:
method Bag(--> Bag) is nodal
Coerce the invocant to Bag, whereby Positionals are treated as lists of values.
(Any) method BagHash
Defined as:
method BagHash(--> BagHash) is nodal
Coerce the invocant to BagHash, whereby Positionals are treated as lists of values.
(Any) method Set
Defined as:
method Set(--> Set) is nodal
Coerce the invocant to Set, whereby Positionals are treated as lists of values.
(Any) method SetHash
Defined as:
method SetHash(--> SetHash) is nodal
Coerce the invocant to SetHash, whereby Positionals are treated as lists of values.
(Any) method Mix
Defined as:
method Mix(--> Mix) is nodal
Coerce the invocant to Mix, whereby Positionals are treated as lists of values.
(Any) method MixHash
Defined as:
method MixHash(--> MixHash) is nodal
Coerce the invocant to MixHash, whereby Positionals are treated as lists of values.
(Any) method Supply
Defined as:
method Supply(--> Supply) is nodal
Coerce the invocant first to a list
by applying the invocant's .list
method, and then to a Supply.
(Any) method min
Defined As:
multi method min(--> Any)multi method min( --> Any)
Coerces to Iterable and returns the numerically smallest element.
If a Callable positional argument is provided, each value is passed into the filter, and its return value is compared instead of the original value. The original value is still the one returned from min
.
say (1,7,3).min(); # OUTPUT:«1»say (1,7,3).min(); # OUTPUT:«7»
(Any) method max
Defined As:
multi method max(--> Any)multi method max( --> Any)
Coerces to Iterable and returns the numerically largest element.
If a Callable positional argument is provided, each value is passed into the filter, and its return value is compared instead of the original value. The original value is still the one returned from max
.
say (1,7,3).max(); # OUTPUT:«7»say (1,7,3).max(); # OUTPUT:«1»
(Any) method minmax
Defined As:
multi method minmax(--> Range)multi method minmax( --> Range)
Returns a Range from the smallest to the largest element.
If a Callable positional argument is provided, each value is passed into the filter, and its return value is compared instead of the original value. The original values are still used in the returned Range.
say (1,7,3).minmax(); # OUTPUT:«1..7»say (1,7,3).minmax(); # OUTPUT:«7..1»
(Any) method minpairs
Defined As:
multi method minpairs(Any: --> Seq)
Calls .pairs
and returns a Seq with all of the Pairs with minimum values, as judged by the cmp
operator:
<a b c a b c>.minpairs.perl.put; # OUTPUT: «(0 => "a", 3 => "a").Seq»%(:42a, :75b).minpairs.perl.put; # OUTPUT: «(:a(42),).Seq»
(Any) method maxpairs
Defined As:
multi method maxpairs(Any: --> Seq)
Calls .pairs
and returns a Seq with all of the Pairs with maximum values, as judged by the cmp
operator:
<a b c a b c>.maxpairs.perl.put; # OUTPUT: «(2 => "c", 5 => "c").Seq»%(:42a, :75b).maxpairs.perl.put; # OUTPUT: «(:b(75),).Seq»
(Any) method keys
Defined As:
multi method keys(Any: --> List)multi method keys(Any: --> List)
For defined Any returns its keys after calling list
on it, otherwise calls list
and returns it.
say Any.keys; # OUTPUT: «()»
(Any) method flatmap
Defined As:
method flatmap(Any: --> Seq)
Coerces the Any to a list
by applying the .list
method and uses List.flatmap
on it.
say Any.flatmap(); # OUTPUT: «((Any))»
In the case of Any, Any.list
returns a 1-item list, as is shown.
(Any) method roll
Defined As:
multi method roll(--> Any)multi method roll( --> Seq)
Coerces the invocant Any to a list
by applying the .list
method and uses List.roll
on it.
say Any.roll; # OUTPUT: «(Any)»say Any.roll(5); # OUTPUT: «((Any) (Any) (Any) (Any) (Any))»
(Any) method pick
Defined As:
multi method pick(--> Any)multi method pick( --> Seq)
Coerces the Any to a list
by applying the .list
method and uses List.pick
on it.
say Any.pick; # OUTPUT: «(Any)»say Any.pick(5); # OUTPUT: «((Any))»
(Any) method skip
Defined As:
multi method skip(--> Seq)multi method skip( --> Seq)
Creates a Seq from 1-item list's iterator and uses Seq.skip
on it.
say Any.skip; # OUTPUT: «()»say Any.skip(5); # OUTPUT: «()»say Any.skip(-1); # OUTPUT: «((Any))»say Any.skip(*-1); # OUTPUT: «((Any))»
(Any) method prepend
Defined As:
multi method prepend(--> Array)multi method prepend( --> Array)
Initializes Any variable as empty Array and calls Array.prepend
on it.
my ;say .prepend; # OUTPUT: «[]»say ; # OUTPUT: «[]»my ;say .prepend(1,2,3); # OUTPUT: «[1 2 3]»
(Any) method unshift
Defined As:
multi method unshift(--> Array)multi method unshift( --> Array)
Initializes Any variable as empty Array and calls Array.unshift
on it.
my ;say .unshift; # OUTPUT: «[]»say ; # OUTPUT: «[]»my ;say .unshift([1,2,3]); # OUTPUT: «[[1 2 3]]»
(Any) method first
Defined As:
method first(Mu ?, :, :, :, :)
Treats the Any
as a 1-item list and uses List.first
on it.
say Any.first; # OUTPUT: «(Any)»
(Any) method unique
Defined As:
method unique(:, : --> Seq)
Treats the Any
as a 1-item list and uses List.unique
on it.
say Any.unique; # OUTPUT: «((Any))»
(Any) method repeated
Defined As:
method repeated(:, : --> Seq)
Treats the Any
as a 1-item list and uses List.repeated
on it.
say Any.repeated; # OUTPUT: «()»
(Any) method squish
Defined As:
method squish(:, : --> Seq)
Treats the Any
as a 1-item list and uses List.squish
on it.
say Any.squish; # OUTPUT: «((Any))»
(Any) method permutations
Defined As:
method permutations(--> Seq)
Treats the Any
as a 1-item list and uses List.permutations
on it.
say Any.permutations; # OUTPUT: «(((Any)))»
(Any) method categorize
Defined As:
method categorize( --> Hash)
Treats the Any
as a 1-item list and uses List.categorize
on it.
say Any.categorize(); # OUTPUT: «{(Any) => [(Any)]}»
(Any) method classify
Defined As:
method classify( -->Hash)
Treats the Any
as a 1-item list and uses List.classify
on it.
say Any.classify(); # OUTPUT: «{(Any) => [(Any)]}»
(Any) method produce
(Any) method pairs
Defined As:
multi method pairs(Any: -->List)multi method pairs(Any: -->List)
Returns an empty List if the invocant is undefined, otherwise converts the invocant to a List via the list
method and calls List.pairs on it:
say Any.pairs; # OUTPUT: «()»my ;say .pairs; # OUTPUT: «()»= Any.new;say .pairs; # OUTPUT: «(0 => Any.new)»
(Any) method antipairs
Defined As:
multi method antipairs(Any: -->List)multi method antipairs(Any: -->List)
Applies the method List.antipairs to the invocant, if it is defined, after having invoked list
on it. If the invocant is not defined, it returns an empty List:
my ;say .antipairs; # OUTPUT: «()»= Any.new;say .antipairs; # OUTPUT: «(Any.new => 0)»
(Any) method kv
Defined As:
multi method kv(Any: -->List)multi method kv(Any: -->List)
Returns an empty List if the invocant is not defined, otherwise it does invoke list
on the invocant and then returns the result of List.kv on the latter:
my ;say .kv; # OUTPUT: «()»= Any.new;say .kv; # OUTPUT: «(0 Any.new)»say Any.kv; # OUTPUT: «()»
(Any) method toggle
Defined as:
method toggle(Any: * where .all ~~ Callable, Bool : --> Seq)
Iterates over the invocant, producing a Seq, toggling whether the received values are propagated to the result on and off, depending on the results of calling Callables in @conditions
:
say ^10 .toggle: * < 4, * %% 2, ; # OUTPUT: «(0 1 2 3 6 7)»say ^10 .toggle: :off, * > 4; # OUTPUT: «(5 6 7 8 9)»
Imagine a switch that's either on or off (True
or False
), and values are produced if it's on. By default, the initial state of that switch is in "on" position, unless :$off
is set to a true value, in which case the initial state will be "off".
A Callable from the head of @conditions
is taken (if any are available) and it becomes the current tester. Each value from the original sequence is tested by calling the tester Callable with that value. The state of our imaginary switch is set to the return value from the tester: if it's truthy, set switch to "on", otherwise set it to "off".
Whenever the switch is toggled (i.e. switched from "off" to "on" or from "on" to "off"), the current tester Callable is replaced by the next Callable in @conditions
, if available, which will be used to test any further values. If no more tester Callables are available, the switch will remain in its current state until the end of iteration.
# our original sequence of elements:say list ^10; # OUTPUT: «(0 1 2 3 4 5 6 7 8 9)»# toggled result:say ^10 .toggle: * < 4, * %% 2, ; # OUTPUT: «(0 1 2 3 6 7)»# First tester Callable is `* < 4` and initial state of switch is "on".# As we iterate over our original sequence:# 0 => 0 < 4 === True switch is on, value gets into result, switch is# toggled, so we keep using the same Callable:# 1 => 1 < 4 === True same# 2 => 2 < 4 === True same# 3 => 3 < 4 === True same# 4 => 4 < 4 === False switch is now off, "4" does not make it into the# result. In addition, our switch got toggled, so# we're switching to the next tester Callable# 5 => 5 %% 2 === False switch is still off, keep trying to find a value# 6 => 6 %% 2 === True switch is now on, take "6" into result. The switch# toggled, so we'll use the next tester Callable# 7 => is-prime(7) === True switch is still on, take value and keep going# 8 => is-prime(8) === False switch is now off, "8" does not make it into# the result. The switch got toggled, but we# don't have any more tester Callables, so it# will remain off for the rest of the sequence.
Since the toggle of the switch's state loads the next tester Callable, setting :$off
to a True
value affects when first tester is discarded:
# our original sequence of elements:say <0 1 2>; # OUTPUT: «(0 1 2)»# toggled result:say <0 1 2>.toggle: * > 1; # OUTPUT: «()»# First tester Callable is `* > 1` and initial state of switch is "on".# As we iterate over our original sequence:# 0 => 0 > 1 === False switch is off, "0" does not make it into result.# In addition, switch got toggled, so we change the# tester Callable, and since we don't have any more# of them, the switch will remain "off" until the end
# our original sequence of elements:say <0 1 2>; # OUTPUT: «(0 1 2)»# toggled result:say <0 1 2>.toggle: :off, * > 1; # OUTPUT: «(2)»# First tester Callable is `* > 1` and initial state of switch is "off".# As we iterate over our original sequence:# 0 => 0 > 1 === False switch is off, "0" does not make it into result.# The switch did NOT get toggled this time, so we# keep using our current tester Callable# 1 => 1 > 1 === False same# 2 => 2 > 1 === True switch is on, "2" makes it into the result
(Any) method tree
Defined As:
method tree(--> Any)
Returns the class if it's undefined or if it's not iterable, returns the result of applying the tree
method to the elements if it's Iterable.
say Any.tree; # OUTPUT: «Any»
.tree
has different prototypes for Iterable elements.
my = ( 'A', ('B','C', ('E','F','G')));say .tree(1).flat.elems; # OUTPUT: «6»say .tree(2).flat.elems; # OUTPUT: «2»say .tree( *.join("-"), *.join("—"), *.join("|" )); # OUTPUT: «A-B—C—E|F|G»
With a number, it iteratively applies tree
to every element in the lower level; the first instance will apply .tree(0)
to every element in the array, and likewise for the next example.
The second prototype applies the Whatever
code passed as arguments to every level in turn; the first argument will go to level 1 and so on. tree
can, thus, be a great way to process complex all levels of complex, multi-level, data structures.
(Any) method nl-out
Defined As:
method nl-out(--> Str)
Returns Str with the value of "\n". See IO::Handle.nl-out
for the details.
say Any.nl-out; # OUTPUT: «»
(Any) method invert
Defined As:
method invert(--> List)
Returns an empty List.
say Any.invert; # OUTPUT: «()»
(Any) method combinations
Defined As:
method combinations(--> Seq)
Treats the Any
as a 1-item list and uses List.combinations
on it.
say Any.combinations; # OUTPUT: «(() ((Any)))»
(Any) method iterator
Defined As:
method iterator(--> Iterator)
Coerces the Any
to a list
by applying the .list
method and uses iterator
on it.
my = Any.iterator;say .pull-one; # OUTPUT: «(Any)»say .pull-one; # OUTPUT: «IterationEnd»
(Any) method grep
Defined As:
method grep(Mu , :, :, :, : --> Seq)
Coerces the Any
to a list
by applying the .list
method and uses List.grep
on it.
Based on $matcher
value can be either ((Any))
or empty List.
my ;say .grep(); # OUTPUT: «((Any))»say .grep(); # OUTPUT: «()»
(Any) method append
Defined As:
proto method append(|) is nodalmulti method append(Any \SELF: |values --> Array)
In the case the instance is not a positional-thing, it instantiate it as a new Array, otherwise clone the current instance. After that, it appends the values passed as arguments to the array obtained calling Array.append
on it.
my ;say .append; # OUTPUT: «[]»my ;say .append((1,2,3)); # OUTPUT: «[1 2 3]»
(Any) method values
Defined As:
method values(--> List)
Returns an empty List.
(Any) method collate
Defined As:
method collate(--> Seq)
TODO
(Any) method cache
Defined As:
method cache(--> List)
Provides a List representation of the object itself, calling the method list
on the instance.
Routines supplied by class Mu
Map inherits from class Mu, which provides the following methods:
(Mu) method defined
Declared as
multi method defined( --> Bool)
Returns False
on the type object, and True
otherwise.
say Int.defined; # OUTPUT: «False»say 42.defined; # OUTPUT: «True»
Very few types (like Failure) override defined
to return False
even for instances:
sub fails() ;say fails().defined; # OUTPUT: «False»
(Mu) routine defined
Declared as
multi sub defined(Mu --> Bool)
invokes the .defined
method on the object and returns its result.
(Mu) routine isa
multi method isa(Mu --> Bool)multi method isa(Str --> Bool)
Returns True
if the invocant is an instance of class $type
, a subset type or a derived class (through inheritance) of $type
.
my = 17;say .isa("Int"); # OUTPUT: «True»say .isa(Any); # OUTPUT: «True»
A more idiomatic way to do this is to use the smartmatch operator ~~ instead.
my = "String";say ~~ Str; # OUTPUT: «True»
(Mu) routine does
method does(Mu --> Bool)
Returns True
if and only if the invocant conforms to type $type
.
my = Date.new('2016-06-03');say .does(Dateish); # True (Date does role Dateish)say .does(Any); # True (Date is a subclass of Any)say .does(DateTime); # False (Date is not a subclass of DateTime)
Using the smart match operator ~~ is a more idiomatic alternative.
my = Date.new('2016-06-03');say ~~ Dateish; # OUTPUT: «True»say ~~ Any; # OUTPUT: «True»say ~~ DateTime; # OUTPUT: «False»
(Mu) routine Bool
multi sub Bool(Mu --> Bool)multi method Bool( --> Bool)
Returns False
on the type object, and True
otherwise.
Many built-in types override this to be False
for empty collections, the empty string or numerical zeros
say Mu.Bool; # OUTPUT: «False»say Mu.new.Bool; # OUTPUT: «True»say [1, 2, 3].Bool; # OUTPUT: «True»say [].Bool; # OUTPUT: «False»say %( hash => 'full' ).Bool; # OUTPUT: «True»say .Bool; # OUTPUT: «False»say "".Bool; # OUTPUT: «False»say 0.Bool; # OUTPUT: «False»say 1.Bool; # OUTPUT: «True»say "0".Bool; # OUTPUT: «True»
(Mu) method Capture
Declared as:
method Capture(Mu: --> Capture)
Returns a Capture with named arguments corresponding to invocant's public attributes:
.new.Capture.say; # OUTPUT: «\(:bar("something else"), :foo(42))»
(Mu) method Str
multi method Str(--> Str)
Returns a string representation of the invocant, intended to be machine readable. Method Str
warns on type objects, and produces the empty string.
say Mu.Str; # Use of uninitialized value of type Mu in string context.
(Mu) routine gist
multi sub gist(+args --> Str)multi method gist( --> Str)
Returns a string representation of the invocant, optimized for fast recognition by humans. As such lists will be truncated at 100 elements. Use .perl
to get all elements.
The default gist
method in Mu
re-dispatches to the perl method for defined invocants, and returns the type name in parenthesis for type object invocants. Many built-in classes override the case of instances to something more specific that may truncate output.
gist
is the method that say calls implicitly, so say $something
and say $something.gist
generally produce the same output.
say Mu.gist; # OUTPUT: «(Mu)»say Mu.new.gist; # OUTPUT: «Mu.new»
(Mu) routine perl
multi method perl(--> Str)
Returns a Perlish representation of the object (i.e., can usually be re-evaluated with EVAL to regenerate the object). The exact output of perl
is implementation specific, since there are generally many ways to write a Perl expression that produces a particular value
(Mu) method item
method item(Mu \item:) is raw
Forces the invocant to be evaluated in item context and returns the value of it.
say [1,2,3].item.perl; # OUTPUT: «$[1, 2, 3]»say %( apple => 10 ).item.perl; # OUTPUT: «${:apple(10)}»say "abc".item.perl; # OUTPUT: «"abc"»
(Mu) method self
method self(--> Mu)
Returns the object it is called on.
(Mu) method clone
method clone(*)
Creates a shallow clone of the invocant, including shallow cloning of private attributes. Alternative values for public attributes can be provided via named arguments with names matching the attributes' names.
my = Point2D.new(x => 2, y => 3);say ; # OUTPUT: «Point(2, 3)»say .clone(y => -5); # OUTPUT: «Point(2, -5)»
Note that .clone
does not go the extra mile to shallow-copy @.
and %.
sigiled attributes and, if modified, the modifications will still be available in the original object:
my = Foo.new;with my = .clone# Hash and Array attribute modifications in clone appear in original as well:say ; # OUTPUT: «Foo.new(foo => 42, bar => ["Z", "Y"], baz => {:X("W"), :Z("Y")}, …»say ; # OUTPUT: «Foo.new(foo => 70, bar => ["Z", "Y"], baz => {:X("W"), :Z("Y")}, …».boo.(); # OUTPUT: «Hi».boo.(); # OUTPUT: «Bye»
To clone those, you could implement your own .clone
that clones the appropriate attributes and passes the new values to Mu.clone
, for example, via nextwith
. Alternatively, your own .clone
could clone self first (using self.Mu::clone
or callsame
) and then manipulate the clone as needed, before returning it.
my = Bar.new;with my = .clone# Hash and Array attribute modifications in clone do not affect original:say ; # OUTPUT: «Bar.new(foo => ["a", "b"], bar => {:a("b"), :c("d")})»say ; # OUTPUT: «Bar.new(foo => ["Z", "Y"], bar => {:X("W"), :Z("Y")})»
(Mu) method new
multi method new(*)
Default method for constructing (create + initialize) new objects of a class. This method expects only named arguments which are then used to initialize attributes with accessors of the same name.
Classes may provide their own new
method to override this default.
new
triggers an object construction mechanism that calls submethods named BUILD
in each class of an inheritance hierarchy, if they exist. See the documentation on object construction for more information.
(Mu) method bless
method bless(* --> Mu)
Lower-level object construction method than new
.
Creates a new object of the same type as the invocant, uses the named arguments to initialize attributes, and returns the created object.
You can use this method when writing custom constructors:
my = Point.new(-1, 1);
(Though each time you write a custom constructor, remember that it makes subclassing harder).
(Mu) method CREATE
method CREATE(--> Mu)
Allocates a new object of the same type as the invocant, without initializing any attributes.
say Mu.CREATE.defined; # OUTPUT: «True»
(Mu) method print
multi method print(--> Bool)
Prints value to $*OUT
after stringification using .Str
method without adding a newline at end.
"abc\n".print; # RESULT: «abc»
(Mu) method put
multi method put(--> Bool)
Prints value to $*OUT
, adding a newline at end, and if necessary, stringifying non-Str
object using the .Str
method.
"abc".put; # RESULT: «abc»
(Mu) method say
multi method say(--> Bool)
Prints value to $*OUT
after stringification using gist method with newline at end. To produce machine readable output use .put
.
say 42; # OUTPUT: «42»
(Mu) method ACCEPTS
multi method ACCEPTS(Mu: )
ACCEPTS
is the method that smart matching with the infix ~~ operator and given/when invokes on the right-hand side (the matcher).
The Mu:U
multi performs a type check. Returns True
if $other
conforms to the invocant (which is always a type object or failure).
say 42 ~~ Mu; # OUTPUT: «True»say 42 ~~ Int; # OUTPUT: «True»say 42 ~~ Str; # OUTPUT: «False»
Note that there is no multi for defined invocants; this is to allow autothreading of junctions, which happens as a fallback mechanism when no direct candidate is available to dispatch to.
(Mu) method WHICH
multi method WHICH(--> ObjAt)
Returns an object of type ObjAt which uniquely identifies the object. Value types override this method which makes sure that two equivalent objects return the same return value from WHICH
.
say 42.WHICH eq 42.WHICH; # OUTPUT: «True»
(Mu) method WHERE
method WHERE(--> Int)
Returns an Int
representing the memory address of the object.
(Mu) method WHY
multi method WHY(--> Pod::Block::Declarator)
Returns the attached Pod::Block::Declarator.
For instance:
sub cast(Spell )say .WHY;# OUTPUT: «Initiate a specified spell normally(do not use for class 7 spells)»
See Pod declarator blocks for details about attaching Pod to variables, classes, functions, methods, etc.
(Mu) trait is export
multi sub trait_mod:<is>(Mu \type, :!)
Marks a type as being exported, that is, available to external users.
my is export
A user of a module or class automatically gets all the symbols imported that are marked as is export
.
See Exporting and Selective Importing Modules for more details.
(Mu) method return
method return()
The method return
will stop execution of a subroutine or method, run all relevant phasers and provide invocant as a return value to the caller. If a return type constraint is provided it will be checked unless the return value is Nil
. A control exception is raised and can be caught with CONTROL.
sub f ;say f(); # OUTPUT: «any(1, 2, 3)»
(Mu) method return-rw
Same as method return
except that return-rw
returns a writable container to the invocant (see more details here: return-rw
).
(Mu) method emit
method emit()
Emits the invocant into the enclosing supply or react block.
react# OUTPUT:# received Str (foo)# received Int (42)# received Rat (0.5)
(Mu) method take
method take()
Returns the invocant in the enclosing gather block.
sub insert(, +)say insert ':', <a b c>;# OUTPUT: «(a : b : c)»
(Mu) routine take
sub take(\item)
Takes the given item and passes it to the enclosing gather
block.
my = 6;my = 49;gather for ^.say; # six random values
(Mu) routine take-rw
sub take-rw(\item)
Returns the given item to the enclosing gather
block, without introducing a new container.
my = 1...3;sub f();for f() ;say ;# OUTPUT: «[2 3 4]»
(Mu) method so
method so()
Returns a Bool
value representing the logical non-negation of an expression. One can use this method similarly to the English sentence: "If that is so, then do this thing". For instance,
my = <-a -e -b -v>;my = any() eq '-v' | '-V';if .so# OUTPUT: «Verbose option detected in arguments»
(Mu) method not
method not()
Returns a Bool
value representing the logical negation of an expression. Thus it is the opposite of so
.
my = <-a -e -b>;my = any() eq '-v' | '-V';if .not# OUTPUT: «Verbose option not present in arguments»
Since there is also a prefix version of not
, the above code reads better like so:
my = <-a -e -b>;my = any() eq '-v' | '-V';if not# OUTPUT: «Verbose option not present in arguments»