=head1 Title Synopsis 29 - Builtin Functions =head1 Version Author: Rod Adams Maintainer: Larry Wall Date: 12 Mar 2005 Last Modified: 15 May 2006 Version: 3 This document attempts to document the list of builtin functions in Perl 6. It assumes familiarity with Perl 5 and prior synopses. The document is now the official S29. It's still here in the pugs repository temporarily to allow easy access to pugs implementors, but eventually it will be copied over to svn.perl.org. Despite its being "official", feel free to hack on it as long as it's in the pugs space. -law =head1 Notes In Perl 6, all builtin functions belong to a named package. Not all functions are guaranteed to be imported into the global package C<::*>. In addition, the list of functions imported into C<::*> 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. =head1 Type Declarations The following type declarations are assumed: =over =item AnyChar The root class of all "character" types, regardless of level. This is a subtype of C, limited to a length of 1 at it's highest supported Unicode level. The type name C is aliased to the maximum supported Unicode level in the current lexical scope (where "current" is taken to mean the eventual lexical scope for generic code (roles and macros), not the scope in which the generic code is defined). In other words, use C when you don't care which level you're writing for. Subclasses (things that are C): =over =item LinguaChar or Ling (language-defined characters) =item GraphemeChar or Graf (language-independent graphemes) =item CodePoint or Uni (Unicode codepoints) =item Byte Yes, Byte is both a string and a number. =back =item MatchTest subset MatchTest of Item | Junction; Used to supply a test to match against. Assume C<~~> will be used against it. =back =head1 Function Packages =head2 Math::Basic =over =item abs our Num multi Num::abs ( Num $x ) our Num multi Math::Basic::abs ( Num $x ) Absolute Value. =item floor our Int multi Num::floor ( Num $x ) Returns the highest integer not greater than $x. =item ceiling our Int multi Num::ceiling ( Num $x ) &Num::ceil ::= &Num::ceiling; Returns the lowest integer not less than $x. =item round our Int multi Num::round ( Num $x ) our Int multi Int ( Num $x ) Returns the nearest integer to $x. The algorithm is floor($x + 0.5). (Other rounding algorithms will be given extended names beginning with "round".) =item truncate our Int multi Num::truncate ( Num $x ) our &Num::int ::= &Num::truncate; Returns the closest integer to $x whose absolute value is not greater than the absolute value of $x. (In other words, just chuck any fractional part.) This is the default rounding function used by an C cast, for historic reasons. But see Int constructor above for a rounded version. =item exp our Num multi Num::exp ( Num $exponent: Num :$base = Num::e ) our Num multi Math::Basic::exp ( Num $exponent, Num :$base = Num::e ) Performs similar to C<$base ** $exponent>. C<$base> defaults to the constant I. =item log our Num multi Num::log ( Num $x: Num :$base ) our Num multi Math::Basic::log ( Num $x, Num :$base ) Logarithm of base C<$base>, default Natural. Calling with C<$x == 0> is an error. =item log10 &log10 := &log.assuming:base(10); =item rand our Num multi Math::Basic::rand ( Num $x = 1 ) Pseudo random number in range C<< 0 ..^ $x >>. That is, C<0> is theoretically possible, while C<$x> is not. =item sign our Int multi Num::sign ( Num $x ) our Int multi Math::Basic::sign ( Num $x ) if !defined($x) { return undef }; if $x < 0 { return -1 }; if $x > 0 { return 1 }; if $x == 0 { return 0 }; fail; } or more succinctly: our Int multi Math::Basic::sign ( Num $x ) $x <=> 0; } =item srand multi Math::Basic::srand ( Num $seed = default_seed_algorithm()) Seed the generator C uses. C<$seed> defaults to some combination of various platform dependent characteristics to yield a non-deterministic seed. Note that you get one C for free when you start a Perl program, so you I call C yourself if you wish to specify a deterministic seed (or if you wish to be differently nondeterministic). =item sqrt our Num multi Num::sqrt ( Num $x ) our Complex multi Complex::sqrt ( Num $x ) our Complex multi Complex::sqrt ( Complex $x ) our Num multi Math::Basic::sqrt ( Num $x ) C<$x ** 0.5> =item e constant Num Num::e = exp(1); =item pi constant Num Num::pi = atan(1,1) * 4; constant Int Int::pi = 3; =item i constant Complex Complex::i = Complex::sqrt(-1); =item one constant Int Int::one = round(-e ** (-i * pi)); # :-) =back =head2 Math::Trig =over 4 =item I our Num multi Num::func ( Num $x : :$base = 'radians' ) our Num multi Math::Trig::func ( Num $x, :$base = 'radians' ) where I 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 C<:$base> is used to declare 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. Note that module currying can be used within a lexical scope to specify a consistent base so you don't have to supply it with every call: my module Trig ::= Math::Trig.assuming(:base); This overrides the default of "radians". =item atan our Num multi Math::Trig::atan2 ( Num $y, Num $x = 1 : Num :$base ) This second form of C computes the arctangent of $y/$x, and takes the quadrant into account. Otherwise behaves as other trigonometric functions. [Note: changed atan back to atan2, or the default $x = 1 will confuse MMD. The other alternative would be to remove the default. --law] =back =head2 Array =over =item delete our List multi method Array::delete (@array : *@indices ) Sets elements specified by C<@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 C definition. C<@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 C. =item exists our Bool multi method Array::exists (@array : Int *@indices ) 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 C. =item pop &Array::pop := &Array::splice.assuming(:offset(-1) :length(1)); our Scalar multi Array::pop ( ) Array::pop @+_; } =item push our Int multi Array::push ( @array is rw : *@values ) Array::splice(@array, @array.elems, 0, @values); @array.elems; } =item shift &Array::shift := &Array::splice.assuming(:offset(0) :length(1)); our Scalar multi Array::shift ( ) Array::shift @+_; } =item splice multi List Array::splice ( @array is rw : Int $offset = 0, Int $length, *@values ) is rw Behaves similar as Perl 5 C. If C<@array> is multidimensional, C operates only on the first dimension, and works with Array References. =item unshift our Int multi Array::unshift ( @array is rw : *@values ) Array::splice(@array, 0, 0, @values); @array.elems; } =item keys =item kv =item pairs =item values multi Int|List Array::keys ( @array : MatchTest *@indextests ) multi Int|List Array::kv ( @array : MatchTest *@indextests ) multi Int|(List of Pair) Array::pairs (@array : MatchTest *@indextests ) multi Int|List Array::values ( @array : MatchTest *@indextests ) (XXX these signatures are wrong. -luqui) Iterates the elements of C<@array>, in order. If C<@indextests> are provided, only elements whose indices match C<$index ~~ any(@indextests)> are iterated. What is returned at each element of the iteration varies with function. C returns the value of the associated element; C returns a 2 element list in (index, value) order, C a C. C<@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. =back =head2 List =over =item grep our Lazy multi Array::grep ( @values : Code *&test ) our Lazy multi Array::grep ( @values : MatchTest $test ) our Lazy multi List::grep ( MatchTest $test : *@values ) gather { for @values -> $x { take $x if $x ~~ $test; } } } =item join our Str multi Array::join ( @values : Str $delimiter ) our Str multi List::join ( Str $delimiter : *@values ) my $str = ~@values[0]; for 1..@values.end { $str ~= $delimiter ~ @values[$_]; } $str; } &join := &join.assuming:delimiter(' '); =item map our Lazy multi Array::map ( @values : Code *&expression ) our Lazy multi List::map ( Code $expression : *@values ) gather { while @values { take $expression .( splice(@values, 0, $expression.arity) ); } } } =item reduce our Scalar multi Array::reduce ( @values : Code *&expression ) our Scalar multi List::reduce ( Code $expression : *@values ) my $res; for @values -> $cur { FIRST {$res = $cur; next;} $res = &$expression($res, $cur); } $res; } =item reverse our Hash multi Hash::reverse ( %hash ) (my %result){%hash.values} = %hash.keys; %result; } multi Lazy Array::reverse ( @values ) multi Lazy List::reverse ( *@values ) gather { 1 while take pop @values; } } multi Str Str::reverse ( $str ) split('', $str).reverse.join ) =item sort subset KeyExtractor of Code(Any --> Any); subset Comparator of Code(Any, Any --> Int ); subset SortCriterion of KeyExtractor | Comparator | Pair(KeyExtractor, Comparator); our Array multi Array::sort( @values is rw, *&by: Bit :$inplace ) our Array multi Array::sort( @values is rw, SortCriterion @by: Bit :$inplace ) our Array multi Array::sort( @values is rw: SortCriterion :$by = &infix:, Bit :$inplace ) our List multi List::sort( SortCriterion @by: *@values ) our List multi List::sort( SortCriterion $by = &infix:, *@values ) Returns C<@values> sorted, using criteria C<$by> or C<@by> for comparisons. C<@by> differs from C<$by> in that each criteria is applied, in order, until a non-zero (tie) result is achieved. Criterion can take a few different forms: =over 8 =item Comparator A closure with arity of 2, which returns negative/zero/positive, signaling the first arguement should be before/tied with/after the second in the final ordering of the List. aka "The Perl 5 way" =item KeyExtractor A closure with arity of 1, which returns the "key" by which to sort. If the closure returns a Num, C=E> is used for comparison, otherwise C. =item Pair(KeyExtractor, Comparator) A combination of the two methods above, for when one wishs to take advantage of the internal caching of keys that is expected to happen, but wishes to compare them with something other than C=E> or C. =back Any Criterion may recieve either or both of the traits C and C to reverse the order of sort, or the adjust the case sensitivity of C as a Comparator. If all criteria are exhausted when comparing two elements, sort should return them in the same relative order they had in C<@values>. If C<$inplace> is specified, the array is sorted in place. See L for more details and examples. =item zip our Lazy multi List::zip ( Array *@lists, Bit :$shortest ) { gather { while $shortest ?? all(@lists) !! any(@lists) { for @lists -> @list { take shift @list; } } } } [Note: This should be the definition of each() now. The zip function needs to build tuples of the "across" values. Also, it maybe probably be in terms of longest non-infinite. -law] =back =head2 Hash =over 4 =item delete our List multi method Hash::delete ( *@keys ) our Scalar multi method Hash::delete ( $key ) is default Deletes the elements specified by C<$key> or C<$keys> from the invocant. returns the value(s) that were associated to those keys. =over =item Unary Form Implementations should create a suitable macro, or otherwise support the unary form C in all its forms. Below are some example translations. This list is I exhaustive. delete %hash{$key} %hash.delete{$key} delete %hash %hash.delete{'key'} delete %hash{@keys} %hash.delete{@keys} =back =item exists our Bool multi method Hash::exists ( $key ) True if invocant has an element whose key matches C<$key>, false otherwise. A unary form is expected. See Hash::delete. See also Code::exists to determine if a function has been declared. (Use defined() to determine whether the function body is defined. A body of ... counts as undefined.) =item keys =item kv =item pairs =item values multi Int|List Hash::keys ( %hash : MatchTest *@keytests ) multi Int|List Hash::kv ( %hash : MatchTest *@keytests ) multi Int|(List of Pair) Hash::pairs (%hash : MatchTest *@keytests ) multi Int|List Hash::values ( %hash : MatchTest *@keytests ) Iterates the elements of C<%hash> in no apparent order, but the order will be the same between successive calls to these functions, as long as C<%hash> doesn't change. If C<@keytests> are provided, only elements whose keys evaluate C<$key ~~ any(@keytests)> as true are iterated. What is returned at each element of the iteration varies with function. C only returns the key; C the value; C returns both as a 2 element list in (key, value) order, C a C. Note that C returns the same as C In Scalar context, they all return the count of elements that would have been iterated. The lvalue form of C is not longer supported. Use the C<.buckets> property instead. =back =head2 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 GChar. [Q: Default can't be LChar because we don't go into "language" mode unless there's a specific language declaration saying either exactly what language we're going into, or what environmental parameter to pay attention to to select our language. So I believe the default should be GChar. -law] Attempting to use a string at a level higher it can support is handled without warning. The current highest supported level of the string is simply mapped Char for Char to the new higher level. However, attempting to stuff something of a higher level a lower-level string is an error (for example, attempting to store Kanji in a Byte string). And explicit conversion function must be used to tell it how you want it encoded. Attempting to use a string at a level lower than what it supports is not allowed. If a function takes a C and returns a C, the returned C will support the same levels as the input, unless specified otherwise. =over =item p5chop our Char multi P5emul::Str::p5chop ( Str $string is rw ) our Char multi P5emul::Str::p5chop ( Str *@strings = ($+_) is rw ) Trims the last character from C<$string>, and returns it. Called with a list, it chops each item in turn, and returns the last character chopped. =item chop our Str method Str::chop ( Str $string: ) Returns string with one Char removed from the end. =item p5chomp our Int multi P5emul::Str::p5chomp ( Str $string is rw ) our Int multi P5emul::Str::p5chomp ( Str *@strings = ($+_) is rw ) Related to C, only removes trailing chars that match C. In either case, it returns the number of chars removed. =item chomp our Str method Str::chomp ( Str $string: ) Returns string with newline removed from the end. An arbitrary terminator can be removed if the input filehandle has marked the string for where the "newline" begins. (Presumably this is stored as a property of the string.) Otherwise a standard newline is removed. Note: Most users should just let their I/O handles autochomp instead. (Autochomping is the default.) =item lc our Str multi Str::lc ( Str $string ) Returns the input string after converting each character to its lowercase form, if uppercase. =item lcfirst our Str multi Str::lcfirst ( Str $string ) Like C, but only affects the first character. =item uc our Str multi Str::uc ( Str $string ) Returns the input string after converting each character to its uppercase form, if lowercase. This is not a Unicode "titlecase" operation, but a full "uppercase". =item ucfirst our Str multi Str::ucfirst ( Str $string ) Performs a Unicode "titlecase" operation on the first character of the string. =item capitalize our Str multi Str::capitalize ( Str $string ) Has the effect of first doing an C on the entire string, then performing a C on it. =item length This word is banned in Perl 6. You must specify units. =item index Needs to be in terms of StrPos, not Int. =item pack =item pos =item quotemeta =item rindex Needs to be in terms of StrPos, not Int. =item split our List multi Str::split ( Str $delimiter , Str $input_, Int $limit = inf ) our List multi Str::split ( Rule $delimiter = /\s+/, Str $input, Int $limit = inf ) our List multi Str::split ( Str $input : Str $delimiter , Int $limit = inf ) our List multi Str::split ( Str $input : Rule $delimiter , Int $limit = inf ) String delimiters must not be treated as rules but as constants. The default is no longer S<' '> since that would be interpreted as a constant. P5's C<< split('S< >') >> will translate to C<.words> or some such. Null trailing fields are no longer trimmed by default. We might add some kind of :trim flag or introduce a trimlist function of some sort. =item sprintf =item substr multi substr (Str $s, StrPos $start : StrPos $end, $replace) multi substr (Str $s, StrPos $start, StrLen $length : $replace) multi substr (Str $s, StrLen $offset : StrLen $length, $replace) =item unpack =item vec Should replace vec with declared arrays of bit, uint2, uint4, etc. =item words our List multi Str::words ( Rule $matcher = /\S+/, Str $input, Int $limit = inf ) our List multi Str::words ( Str $input : Rule $matcher = /\S+/, Int $limit = inf ) =back =head2 Control::Basic =over =item eval multi Control::Basic::eval ( Str $code, Grammar :$lang = CALLER::<$?PARSER>) Execute C<$code> as if it were code written in C<$lang>. The default is the language in effect at the exact location of the eval call. Returns whatever C<$code> returns, or undef on error. =item evalfile multi Control::Basic::evalfile (Str $filename : Grammar :$lang = Perl6) Behaves like, and replaces Perl 5 C, with optional C<$lang> support. =item exit multi Control::Basic::exit ( Int $status = 0) Stops all program execution, and returns C<$status> to the calling environment. =item nothing multi Control::Basic::nothing () No operation. Literally does nothing. =item sleep our Num multi Control::Basic::sleep ( Num $for = Inf ) Attempt to sleep for up to C<$for> seconds. Implementations are obligated to support subsecond resolutions if that is at all possible. [Q: what about multithreading? do we just sleep this thread? need to coordinate with entire async model. -law] =item die =item fail B: Research the exception handling system. =back =head2 Conversions =over =item bless sub =item chr =item ord B: I think these should be strictly Code Point level activitities, but I'm not sure. They likely need to be renamed, as well. =item list our List multi Conversions::List::list ( *@list ) Forces List Context on it's arguements, and returns them. =item item our Item multi Conversions::Item::item ( $item ) Forces generic Item context on its argument, and returns it. =item :16, :8, :2, :10 our Num multi prefix:<:16> ( Str $hexstr ) our Num multi prefix:<:8> ( Str $octstr ) our Num multi prefix:<:2> ( Str $binstr ) our Num multi prefix:<:10> ( Str $decstr ) etc. Interprets string as a number, with a default hexadecimal/octal/binary/decimal radix. Any radix prefix (0b, 0d, 0x, 0o) mentioned inside the string will override this operator (this statement is true: 10 == :8("0d10")), except 0b and 0d will be interpreted as hex digits by :16 (C). Cs on failure. These aren't really functions, syntactically, but adverbial forms that just happen to allow a parenthesize argument. But more typically you'll see :4<222> :16 and such. Replaces Perl 5 C and C. =back =head2 Time::Local =over =item gmtime =item localtime =item time =back =head2 I =over 4 =item defined Same as Perl 5, only takes extra optional argument to ask if value is defined with respect to a particular role: $x.defined(SomeRole); A value may be defined according to one role and undefined according to another. Without the extra argument, defaults to the definition of defined supplied by the type of the object. =item undefine Perl 5's unary C function is renamed C to avoid confusion with the value C (which is always 0-ary now). =item want =item caller =item each Unlike Perl 5's each, C is a general method that traverses any composite container in a type-specific manner. For P5-like traversal, see C or C instead, and put into C instead of C. Perhaps there is a C emulation. =back =head2 Obsolete =over 4 =item dbmopen, dbmclose use DB_File; =item dump Dumped. =item format, formline, write See Exegesis 7. =item /[msg|sem|shm].*/ use IPC::SysV; =item local Replaced by C which, unlike C, defaults to not changing the value. =item ref There is no ref() any more, since it was almost always used to get the type name in Perl 5. If you really want the type name, you can use C<$var.meta.name> or C<$var.^name>. If you really want P5 ref semantics, use C. But if you're just wanting to test against a type, you're likely better off performing an C or C or C, or just C<$var ~~ TYPE>. =item reset Was there a I use for this? =item prototype &func.meta.signature; &func.^signature; =item study Algorithm was too anglo-centric. Could be brought back if generalized somehow. =back =item % $num1 % $num2 Does a floating point modulus operation, i.e. 5.5 % 1 == 0.5 and 5 % 2.5 == 0. =back =head2 Pending Apocalypse The following functions are classified by Apocalypse/Synopsis numbers. =over 4 =item A/S14: Tied Variables tie tied untie (now implemented as container classes? my $foo is ....? is tie the meta operation on the container type for 'rebless' - macro tie ( $var, $class, *@args ) { CODE { variable($var).meta.rebless( $class, *@args ) } } ) These are replaced by container types. The compiler is free to assume that any lexical variable is never going to change its container type unless some representation is made to that effect in the declaration. Note: P5's tied() is roughly replaced by P6's variable(). =item 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 =item A/S??: OS Interaction chroot crypt exec getlogin /[get|set][pw|gr].*/ kill setpgrp setpriority system times ... These are probably going to be part of POSIX, automatically imported to GLOBAL B the platform is the right one Note: system() should be renamed to sys() or sh() or run() or some such to avoid P5-induced boolean inversion confusion, plus huffmanize it a little better. I'm thinking run() might be best for MMD reasons. --law Note: exec should also be renamed to something clearer and "final" and huffmanly longer. I'm thinking runinstead(). And maybe the function behind qq:x should be rungather() rather than readpipe(). -law =item A/S17: Threads and Multiprocessing fork lock wait waitpid # FIXME audrey drafted synopsis 17 =back =head1 Additions Please post errors and feedback to perl6-language. If you are making a general laundry list, please separate messages by topic.