role X::OS
Error reported by the operating system
Common role for all exceptions that are triggered by some error reported by the operating system (failed IO, system calls, fork, memory allocation).
Methods
method os-error
method os-error(--> Str)
Returns the error as reported by the operating system.
Type Graph
X::OS
Stand-alone image: vector
Routines supplied by class Exception
X::OS inherits from class Exception, which provides the following methods:
(Exception) method message
Defined as:
method message(Exception: --> Str)
This is a stub that must be overwritten by subclasses, and should return the exception message.
Special care should be taken that this method does not produce an exception itself.
try die "Something bad happened";if ($!)
(Exception) method backtrace
Defined as:
method backtrace(Exception: --> Backtrace)
Returns the backtrace associated with the exception. Only makes sense on exceptions that have been thrown at least once.
try die "Something bad happened";if ($!)
(Exception) method throw
Defined as:
method throw(Exception:)
Throws the exception.
my = X::AdHoc.new; # Totally finetry .throw; # Throwsif ($!) ; # Suppress the exception
(Exception) method resume
Defined as:
method resume(Exception:)
Resumes control flow where .throw
left it when handled in a CATCH
block.
# For example, resume control flow for any exceptionCATCH
(Exception) method rethrow
Defined as:
method rethrow(Exception:)
Rethrows an exception that has already been thrown at least once. This is different from throw
in that it preserves the original backtrace.
my = X::AdHoc.new(payload => "Bad situation");sub f() ;sub g() ;g;CATCH ;
(Exception) method fail
Defined as:
multi sub fail(*)multi sub fail(Exception )method fail(Exception:)
Exits the calling Routine
and returns a Failure object wrapping the exception $e
- or, for the *@text
form, an X::AdHoc exception constructed from the concatenation of @text
. If the caller activated fatal exceptions via the pragma use fatal;
, the exception is thrown instead of being returned as a Failure
.
sub copy-directory-tree ()
(Exception) method gist
Defined as:
multi method gist(Exception:)
Returns whatever the exception printer should produce for this exception. The default implementation returns message and backtrace separated by a newline.
my = X::AdHoc.new(payload => "This exception is pretty bad");try .throw;if ($!) ;# OUTPUT: «This exception is pretty bad# in block <unit> at <unknown file> line 1»
(Exception) sub die
Defined as:
multi sub die()multi sub die(*)multi sub die(Exception )method die(Exception:)
Throws a fatal Exception. The default exception handler prints each element of the list to $*ERR
(STDERR).
die "Important reason";
If the subroutine form is called without arguments, the value of $!
variable is checked. If it is set to a .DEFINITE
value, its value will be used as the Exception to throw if it's of type Exception, otherwise, it will be used as payload of X::AdHoc exception. If $!
is not .DEFINITE
, X::AdHoc with string "Died"
as payload will be thrown.
(Exception) sub warn
Defined as:
multi sub warn(*)
Throws a resumable warning exception, which is considered a control exception, and hence is invisible to most normal exception handlers. The outermost control handler will print the warning to $*ERR
. After printing the warning, the exception is resumed where it was thrown. To override this behavior, catch the exception in a CONTROL
block. A quietly {...}
block is the opposite of a try {...}
block in that it will suppress any warnings but pass fatal exceptions through.
To simply print to $*ERR
, please use note
instead. warn
should be reserved for use in threatening situations when you don't quite want to throw an exception.
warn "Warning message";
Routines supplied by class Any
X::OS 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
X::OS 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»