Title

[DRAFT] Synopsis 29 - Builtin Functions [DRAFT]

Version

Maintainer:    Rod Adams <rod@rodadams.net>
Date:          12 Mar 2005
Last Modified: 03 Apr 2005

This document attempts to document the list of builtin functions in Perl 6. It assumes familiarity with Perl 5 and prior synopses.

Notes

In Perl 6, all builtin functions belong to a named package. Not all functions are guaranteed to be imported into the global package ::*. In addition, the list of functions imported into ::* will be subject to change with each release of Perl. Authors wishing to "Future Proof" their code should either specifically import the functions they will be using, or always refer to the functions by their full name.

After 6.0.0 comes out, global aliases will not be removed lightly, and will never be removed at all without having gone through a deprecation cycle of at least a year. In any event, you can specify that you want the interface for a particular version of Perl, and that can be emulated by later versions of Perl to the extent that security updates allow.

Where code is given here, it is intended to define semantics, not to dictate implementation.

Type Declarations

The following type declarations are assumed:

Char

The root class of all "character" types, regardless of level.

This is a subtype of Str, limited to a length of 1 at it's highest supported Unicode level.

Subclasses (things that are isa Char):

LanguageChar aka LChar
Grapheme aka Grf
CodePoint aka CdPt
Byte: Yes, Byte is both a string and a number.

MatchTest

type MatchTest ::= Scalar | Junction;

Used to supply a test to match against. Assume ~~ will be used against it.

Function Packages

Math::Basic

abs

multi sub  Num::abs (  Num  $x              ) returns Num
multi sub Math::Basic::abs (: Num ?$x = $CALLER::_ ) returns Num

Absolute Value.

floor

multi sub  Num::floor (  Num  $x            ) returns Int

Returns the highest integer not greater than $x.

ceiling

multi sub  Num::ceiling (  Num  $x          ) returns Int
&Num::ceil ::= &Num::Ceiling;

Returns the lowest integer not less than $x.

round

multi sub  Num::round (  Num  $x            ) returns Int

Returns the nearest integer to $x, away from zero. In other words, the absolute value, rounded up.

truncate

multi sub  Num::truncate (  Num  $x         ) returns Int
our &Num::int ::= &Num::truncate;

Returns the closest integer to $x, rounding towards 0. This is the default rounding function used by an int() cast, for historic reasons.

exp

multi sub  Num::exp (  Num  $exponent             : Num +$base) returns Num
multi sub Math::Basic::exp (: Num ?$exponent = $CALLER::_, Num +$base) returns Num

Performs similar to $base ** $exponent. $base defaults to the constant e.

log

multi sub  Num::log (  Num  $x             : Num +$base) returns Num
multi sub Math::Basic::log (: Num ?$x = $CALLER::_, Num +$base) returns Num

Logarithm of base $base, default Natural. Calling with $x == 0 is an error.

log10

&log10<> := &log<>.assuming:base(10);

rand

multi sub Math::Basic::rand (: Num ?$x = 1) returns Num

Psuedo random number between 0 and $x.

sign

multi sub  Num::sign (  Num  $x             ) returns Int
multi sub Math::Basic::sign (: Num ?$x = $CALLER::_) returns Int {
  if !defined($x) { return undef };
  if $x < 0       { return -1    };
  if $x > 0       { return  1    };
  if $x == 0      { return  0    };
  undef;
}

srand

multi sub Math::Basic::srand (: Num ?$seed)

Seed the generator rand uses. $seed defaults to some combination of various platform dependent characteristics to yield a non- deterministic seed.

sqrt

multi sub  Num::sqrt (  Num  $x             ) returns Num
multi sub Math::Basic::sqrt (: Num ?$x = $CALLER::_) returns Num

$x ** 0.5

Math::Trig

Standard Trig Functions

multi sub Num::func (  Num  $x             : +$base) returns Num
multi sub Math::Trig::func (: Num ?$x = $CALLER::_, +$base) returns Num

where func is one of: sin, cos, tan, asin, acos, atan, sec, cosec, cotan, asec, acosec, acotan, sinh, cosh, tanh, asinh, acosh, atanh, sech, cosech, cotanh, asech, acosech, acotanh.

Performs the various trigonmetric functions.

Option $base is used to declare your how you measure your angles. Given the value of an arc representing a single full revolution.

$base   Result
----    -------
/:i ^r/ Radians  (2*pi)
/:i ^d/ Degrees  (360)
/:i ^g/ Gradians (400)
Num     Units of 1 revolution.

atan

multi sub Math::Trig::atan (Num $y, Num $x : Num +$base) returns Num

This second form of atan computes the arctangent of $y/$x, and takes the quadrant into account. Otherwise behaves as other trigonometric functions. Replaces Perl 5 atan2.

pi

multi sub Math::Trig::pi () returns Num

Array

delete

multi method Array::delete (@array : *@indices) returns List

Sets elements specified by @indices in the invocant to a non-existent state, as if they never had a value. Deleted elements at the end of an Array shorten the length of the Array, unless doing so would violate an is shape() definition.

@indices is interpreted the same way as subscripting is in terms of slices and multidimensionality. See Synopsis 9 for details.

Returns the value(s) previously held in deleted locations.

An unary form is expected. See Hash::delete.

exists

multi method Array::exists (@array : Int *@indices) returns Bool

True if the specified Array element has been assigned to. This is not the same as being defined.

Supplying a different number of indices than invocant has dimensions is an error.

An unary form is expected. See Hash::delete.

pop

&Array::pop<Array> := &Array::splice<Array>.assuming(:offset(-1) :length(1));

multi sub Array::pop () returns Scalar {
  pop @CALLER::_;
}

push

multi sub Array::push (@array is rw : *@values) returns Int {
  Array::splice(@array, @array.elems, 0, @values);
  @array.elems;
}

shift

&Array::shift<Array> := &Array::splice<Array>.assuming(:offset(0) :length(1));

multi sub Array::shift () returns Scalar {
  Array::shift @CALLER::_;
}

splice

multi sub Array::splice (       @array is rw 
                                : Int ?$offset = 0,
                                  Int ?$length,
                                      *@values
                               ) returns List is rw

Behaves similar as Perl 5 splice.

If @array is multidimensional, splice operates only on the first dimension, and works with Array References.

unshift

multi sub Array::unshift (@array is rw : *@values) returns Int {
  Array::splice(@array, 0, 0, @values);
  @array.elems;
}

keys

kv

pairs

values

multi sub Array::keys   (@array : MatchTest *@indextests) returns Int|List
multi sub Array::kv     (@array : MatchTest *@indextests) returns Int|List
multi sub Array::pairs  (@array : MatchTest *@indextests) returns Int|(List of Pair)
multi sub Array::values (@array : MatchTest *@indextests) returns Int|List

Iterates the elements of @array, in order.

If @indextests are provided, only elements whose indices match $index ~~ any(@indextests) are iterated.

What is returned at each element of the iteration varies with function. values returns the value of the associated element; kv returns a 2 element list in (index, value) order, pairs a Pair(index, value).

@array is considered single dimensional. If it is in fact multi- dimensional, the values returned will be array references to the sub array.

In Scalar context, they all return the count of elements that would have been iterated.

List

grep

multi sub Array::grep (@values :      Code *&test  ) returns Lazy
multi sub Array::grep (@values,   MatchTest $test  ) returns Lazy
multi sub  List::grep (MatchTest $test :   *@values) returns Lazy {
  gather {
    for @values -> $x {
      take $x if $x ~~ $test;
    }
  }
}

join

multi sub Array::join (@values,   Str $delimiter) returns Str
multi sub  List::join (Str $delimiter : *@values) returns Str {
  my $str = ~@values[0];
  for 1..@values.end {
    $str ~= $delimiter ~ @values[$_];
  }
  $str;
}
&join<> := &join<Str>.assuming:delimiter(' ');

map

multi sub Array::map (@values,   Code $expression) returns Lazy 
multi sub  List::map (Code $expression : *@values) returns Lazy {
  gather {
    while @values {
      take $expression
         .( splice(@values, 0, $expression.arity) );
    }
  }
}

reduce

multi sub Array::reduce (@values : Code *&expression) returns Scalar
multi sub  List::reduce (Code $expression : *@values) returns Scalar {
  my $res;
  for @values -> $cur {
       FIRST {$res = $cur; next;}
    $res = &$expression($res, $cur);
  }
  $res;
}

reverse

multi sub Hash::reverse (%hash) returns Hash is default {
  my %result;
  for %hash.kv -> $k, $v {
    %result{$v} = $k;
  }
  %result;
}

multi sub Array::reverse (   @values) returns Lazy|Str {
multi sub  List::reverse (: *@values) returns Lazy|Str {
  given want {
    when List {
      gather {
        1 while take pop @values;
      }
    }
    when Scalar {
      reverse @values ==> join;
    }
  }
}

sort

type KeyExtractor  ::= Code(Any) returns Any;
type Comparator    ::= Code(Any, Any) returns Int;
type SortCriterion ::= KeyExtractor
                     | Comparator
                     | Pair(KeyExtractor, Comparator);

multi sub Array::sort(                 @values is rw,
                                             *&by
                             :           Bit +$inplace
                            ) returns Array

multi sub Array::sort(                 @values is rw,
                               SortCriterion  @by
                             :           Bit +$inplace
                            ) returns Array

multi sub Array::sort(                 @values is rw
                             : SortCriterion +$by = &infix:<cmp>,
                                         Bit +$inplace
                            ) returns Array

multi sub  List::sort(  SortCriterion  @by
                             :               *@values
                            ) returns List

multi sub  List::sort(: SortCriterion  $by = &infix:<cmp>,
                                             *@values
                            ) returns List

Returns @values sorted, using criteria $by or @by for comparisions. @by differs from $by in that each criteria is applied, in order, until a non-zero (tie) result is achieved.

Criterion can take a few different forms:

Comparator: A closure with arity of 2, which returns negative/zero/positive, signaling the first arguement should be before/tied with/after the second in the final ordering of the List. aka "The Perl 5 way"
KeyExtractor: A closure with arity of 1, which returns the "key" by which to sort. If the closure returns a Num, <=> is used for comparison, otherwise cmp.
Pair(KeyExtractor, Comparator): A combination of the two methods above, for when one wishs to take advantage of the internal caching of keys that is expected to happen, but wishes to compare them with something other than <=> or cmp.

Any Criterion may recieve either or both of the traits is descending and is insensitive to reverse the order of sort, or the adjust the case sensitivity of cmp as a Comparator.

If all criteria are exhausted when comparing two elements, sort should return them in the same relative order they had in @values.

If $inplace is specified, the array is sorted in place.

See http://www.nntp.perl.org/group/perl.perl6.language/16578 for more details and examples.

zip

multi sub Lists::zip (: Array *@lists, Bit +$shortest) returns Lazy {
  gather {
    while $shortest ?? all (@lists) !! any(@lists) {
      for @lists -> @list {
        take shift @list;
      }
    }
  }
}

Hash

delete

multi method Hash::delete (: *@keys) returns List
multi method Hash::delete (   $key ) returns Scalar is default

Deletes the elements specified by $key or $keys from the invocant. returns the value(s) that were associated to those keys.

Unary Form

Implementations should create a suitable macro, or otherwise support the unary form delete %hash{$key} in all it's forms. Below are some example translations. This list is not exhaustive.

delete %hash{$key}                %hash.delete{$key}
delete %hash<key>                 %hash.delete{'key'}
delete %hash<key1>{@keys}         %hash<key1>.delete{@keys}

exists

multi method Hash::exists ($key) returns Bool

True if invocant has an element whose key matches $key, false otherwise.

An unary form is expected. See Hash::delete

keys

kv

pairs

values

multi sub Hash::keys   (%hash : MatchTest *@keytests) returns Int|List
multi sub Hash::kv     (%hash : MatchTest *@keytests) returns Int|List
multi sub Hash::pairs  (%hash : MatchTest *@keytests) returns Int|(List of Pair)
multi sub Hash::values (%hash : MatchTest *@keytests) returns Int|List

Iterates the elements of %hash in no apparent order, but the order will be the same between successive calls to these functions, as long as %hash doesn't change.

If @keytests are provided, only elements whose keys evaluate $key ~~ any(@keytests) as true are iterated.

What is returned at each element of the iteration varies with function. keys only returns the key; values the value; kv returns both as a 2 element list in (key, value) order, pairs a Pair(key, value).

Note that kv %hash returns the same as zip(keys %hash; values %hash)

In Scalar context, they all return the count of elements that would have been iterated.

The lvalue form of keys is not longer supported. Use the .buckets property instead.

Str

General notes about strings:

A Str can exist at several Unicode levels at once. Which level you interact with typically depends on what your current lexical context has declared the "working unicode level to be". Default is LChars.

Attempting to use a string at a level higher it can support is handled without warning. The highest supported level is simply mapped char for char to the desired level. However, attempting to stuff something into the string at a higher level that doesn't map to the lower level is an error (for example, attempting to store Kanji in a Byte uplifted to an LChar).

Attempting to use a string at a level lower than what it supports is not allowed.

If a function takes a Str and returns a Str, the returned Str will support the same levels as the input, unless specified otherwise.

chop

multi sub Str::chop (  Str  $string is rw                 ) returns Char
multi sub Str::chop (: Str *@strings = ($CALLER::_) is rw ) returns Char

Trims the last character from $string, and returns it. Called with a list, it chops each item in turn, and returns the last character chopped.

chomp

multi sub Str::chomp (  Str  $string is rw                 ) returns Int
multi sub Str::chomp (: Str *@strings = ($CALLER::_) is rw ) returns Int

Related to chop, only removes trailing chars that match /\n/. In either case, it returns the number of chars removed.

Note: Most users should consider setting their I/O handles to autochomp instead of this step.

lc

multi sub Str::lc         (  Str  $string              ) returns Str
multi sub Str::lc         (: Str ?$string = $CALLER::_ ) returns Str

Returns the input string after converting each character to it's lowercase form, if uppercase.

lcfirst

multi sub Str::lcfirst    (  Str  $string              ) returns Str
multi sub Str::lcfirst    (: Str ?$string = $CALLER::_ ) returns Str

Like lc, but only affects the first character.

uc

multi sub Str::uc         (  Str  $string              ) returns Str
multi sub Str::uc         (: Str ?$string = $CALLER::_ ) returns Str

Returns the input string after converting each character to it's uppercase form, if lowercase. This is not a Unicode "titlecase" operation, but a full "uppercase".

ucfirst

multi sub Str::ucfirst    (  Str  $string              ) returns Str
multi sub Str::ucfirst    (: Str ?$string = $CALLER::_ ) returns Str

Performs a Unicode "titlecase" operation on the first character of the string.

capitalize

multi sub Str::capitalize (  Str  $string              ) returns Str
multi sub Str::capitalize (: Str ?$string = $CALLER::_ ) returns Str

Has the effect of first doing an lc on the entire string, then performing a s:g/(\w+)/{ucfirst $1}/ on it.

length

index

pack

pos

quotemeta

rindex

split

multi sub Str::split (  Str $delimiter ,  Str ?$input = $CALLER::_, Int ?$limit = inf ) returns List
multi sub Str::split ( Rule $delimiter ,  Str ?$input = $CALLER::_, Int ?$limit = inf ) returns List
multi sub Str::split (      Str $input :  Str $delimiter          , Int ?$limit = inf ) returns List
multi sub Str::split (      Str $input : Rule $delimiter          , Int ?$limit = inf ) returns List
&split<> := &split<Str>.assuming:delimiter(' ');

sprintf

substr

multi sub substr(Str $s, StrPos $start  : StrPos ?$end,     ?$replace)
multi sub substr(Str $s, StrPos $start,   StrLen $length  : ?$replace)
multi sub substr(Str $s, StrLen $offset : StrLen ?$length,  ?$replace)

unpack

vec

Control::Basic

eval

multi sub Control::Basic::eval (: Str $code = $CALLER::_, Str +$lang = 'Perl6')

Execute $code as if it were code written in $lang. Perl6 is the only required language, but supporting Perl5 is strongly recommended.

Returns whatever $code returns, or undef on error.

evalfile

multi sub Control::Basic::evalfile (Str $filename : Str +$lang = 'Perl6')

Behaves like, and replaces Perl 5 do EXPR, with optional $lang support.

exit

multi sub Control::Basic::exit (: Int ?$status = 0)

Stops all program execution, and returns $status to the calling environment.

nothing

multi sub Control::Basic::nothing ()

No operation. Literally does nothing.

sleep

multi sub Control::Basic::sleep (: Num ?$for = Inf ) returns Num

Attempt to sleep for up to $for seconds. Implementations are only obligated to support integral seconds, but higher resolutions are preferred.

die

fail

TODO: Research the exception handling system.

Conversions

bless

sub

chr

ord

Question: I think these should be strictly Code Point level activitities, but I'm not sure. They likely need to be renamed, as well.

list

multi sub Conversions::List:list (: *@list) returns List

Forces List Context on it's arguements, and returns them.

scalar

multi sub Conversions::Scalar:scalar ($scalar) returns Scalar

Forces generic Scalar context on it's arguement, and returns it.

0x, 0o, 0b, 0d

multi sub prefix::<0x> (: Str ?$hexstr = $CALLER::_) returns Num
multi sub prefix::<0o> (: Str ?$octstr = $CALLER::_) returns Num
multi sub prefix::<0b> (: Str ?$binstr = $CALLER::_) returns Num
multi sub prefix::<0d> (: Str ?$binstr = $CALLER::_) returns Num

Interprets string as a number, with a default hexadecimal/octal/binary/decimal radix. Any radix mentioned inside the string will be override this operator. Returns undef on failure.

Replaces Perl 5 hex and oct.

Time::Local

gmtime
localtime
time

TODO

study
defined
undef
scalar
want
caller

Obsolete

dbmopen, dbmclose

use DB_File;

dump

With Parrot?

each

See Hash::kv or Hash::pairs instead.

format, formline, write

See Exgesis 7.

/[msg|sem|shm].*/

use IPC::SysV;

ref

Can be done with $var.meta.name, but you're likely better off performing an isa, or just $var ~~ TYPE.

reset

Was there a good use for this?

prototype

&func.meta.signature;

Pending Apocalypse

The following functions are pending a future Apocalypse/Synopsis/p6l Discussion before progress can be made:

A/S14: Tied Variables: tie tied untie
A/S16: IPC / IO / Signals: -X accept alarm bind binmode chown close closedir connect eof fcntl fileno flock getc getpeername /[get|set][host|net|proto|serv|sock].*/ glob ioctl link listen lstat mkdir open opendir pipe print printf read readdir readline readlink readpipe recv rename rewinddir rmdir seek seekdir select(both) send setsockopt shutdown slurp socket socketpair stat symlink syscall sysopen sysread sysseek syswrite tell telldir truncate umask unlink utime warn
A/S??: OS Interaction: chroot crypt exec getlogin /[get|set][pw|gr].*/ kill setpgrp setpriority system times
A/S17: Threads and Multiprocessing: fork lock wait waitpid

Additions

Is your favorite function, which you spent weeks successfully arguing on perl6-language to get accepted, nowhere on this document? Have no fear. Email rod@rodadams.net with a brief description and a link to the thread on http://www.nntp.perl.org/group/perl.perl6.language, and it'll get listed.

Post errors to perl6-language.

Provide feedback

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Control::Basic

Conversions

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TODO

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Pending Apocalypse

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Pending Apocalypse

Additions