DESCRIPTION §

A (hopefully) comprehensive list of Perl builtin functions with their Raku equivalents with notes on variations between them where necessary.

NOTE §

This document is an attempt to guide you from the functions in Perl's perlfunc document to their equivalents in Raku. For full documentation on the Raku functions, follow the links in this document to their respective documentation.

One general comment: Raku takes its objects a lot more seriously than Perl. In Raku, everything is an object, although the language is flexible enough to not force you to work in an object oriented manner if you do not wish to do so. What this does mean, however, is that a lot of things that are function calls of the form function(@args) are now also method calls of the form @args.function (In rare cases, there is only a method call). This should be obvious in the following text, but it probably behooves you to get into that frame of mind now.

Also, unless otherwise stated, the use of the term "function" here will mean a function in the style of func(@args), while "method" will refer to a function in the style of @args.func.

Alphabetical listing of Perl functions §

Filetests §

Raku gives you a couple of options when it comes to file tests. You can do a smartmatch (~~) or you can call a method.

In Raku, you don't need to actually open a filehandle in the traditional way (although you can) to do a filetest. You can simply append .IO to the filename. For instance, here is how to check if a file is readable using smartmatch:

'/path/to/file'.IO ~~ :r

You can, of course, use an already opened filehandle. Here, using the filehandle $fh, is an example, using the method syntax for the file test:

$fh.r

Most of the former filetests have colon equivalents for use with smartmatch:

All of these tests can be used as methods (without the colon).

Three tests, however, only have method equivalents:

$fh.modified; # -M $fh 
$fh.accessed; # -A $fh 
$fh.changed;  # -C $fh 

The remaining filetests in Perl do not appear to be implemented in Raku.

The documentation for this can be found at File test operators.

There is more information on reading and writing files at io. Also, the section on open() below may be helpful.

The Raku ecosystem has a module P5-X which exports the behavior as much as possible in Raku.

abs §

Works as a function (abs($x)), but also as a method. One gotcha, however - method calls bind more tightly than -, so, for example, -15.abs evaluates as -(15.abs) giving you -15. In this example, you would have to do something like (-15).abs.

abs also operates on $_ in the absence of a value, but not as a function, and as a method you need to call it as .abs rather than simply abs.

The Raku ecosystem has a module P5math which exports an abs function that mimics the original Perl behavior as much as possible.

accept §

accept is a method you can call on a server, e. g. $server.accept(). Instead of returning a packed address, it returns a socket, most likely an IO::Socket object of some sort.

alarm §

alarm() is no more. But it is possible to have code execute after a certain time has elapsed, or at a given time:

Promise.in(5).then: { say "five seconds have passed" }
 
Promise.at(now + 5).then: { say "five seconds have passed" }

In Raku, this does *not* involve any (dummy) signals.

atan2 §

Available as a function as well as being able to be used as a method. For instance, these are equivalent:

atan2(100);
100.atan2;

bind §

[NEEDS FURTHER RESEARCH] No sign of a socket-related bind() in Raku. At a guess, whatever socket binding is needed happens when you create a new socket object.

binmode §

Instead of this, you would use :bin as the file mode when opening the socket. E. g. my $fh = open("path/to/file", :bin);

bless §

With the changes in class creation in Raku, this may find less use than in Perl, and is a method as well as a function. The Raku docs say "Creates a new object of the same type as the invocant, uses the named arguments to initialize attributes, and returns the created object." If you're porting a module from Perl to Raku, it's quite possible you'll want to use new for creating objects rather than bless, although there may be some situations in which the latter may still be useful.

break §

It does not exist in Raku. For breaking out of given blocks, you should probably take a look at proceed and succeed.

caller §

There are a couple different ways to get at caller information in Raku. The basic functionality is provided through callframe now. However, Raku constructs call frames for regular blocks, not just for subroutines, so there are more frames to look through. The following will retrieve the basic information that caller can return:

my $frame   = callframe(0); # OR just callframe() 
my ($subroutine, $package);
if $frame.code ~~ Routine {
    $subroutine = $frame.code.name;
    $package    = $frame.code.package;
}
my $file    = $frame.file;
my $line    = $frame.line;

Many of the other details returned by caller are specific to Perl and have no meaning in Raku.

You can also get some of the information for the current frame or routine frame by using the dynamic variables &?ROUTINE, &?BLOCK, $?PACKAGE, $?FILE, and $?LINE. For many purposes, Backtrace may provide an easier way to browse through the call stack.

The Raku ecosystem has a module P5caller which exports a caller function that mimics the original Perl behavior as much as possible.

chdir §

Works as it does in Perl but must take an argument. The behavior of chdir() (with regards to looking at HOME and LOGDIR) is not supported.

In Raku, chdir only changes the $*CWD dynamic variable. It does not actually change the default directory from the OS's point of view; the special dynamic-variable routine &*chdir can be used for that, if needed.

This is done this way, because there is no concept of a "default directory per OS thread". And since Raku does not fork, but only does threading, it was felt that the "current directory" concept should be in the $*CWD dynamic variable, which can be lexically scoped, and thus can be thread-safe.

The Raku ecosystem has a module P5chdir which exports a chdir function that mimics the original Perl behavior as much as possible, including looking at HOME and LOGDIR.

chmod §

Functions as under Perl, with the difference that octal numbers are represented differently (0o755 rather than 0755). You may also use it as a method, e. g. $fh.chmod(0o755).

chomp §

The behavior of chomp is different than in Perl. It leaves the target unaffected and returns a copy of the target with a final logical newline removed, e.g. $x = "howdy\n";$y = chomp($x); results in $x containing "howdy\n" and $y containing "howdy". Also works as a method, e.g. $y = $x.chomp. As with many other methods, also works with assignment to modify the target in place, e.g. $x.=chomp results in $x containing "howdy".

Note that chomp() (without arguments) is not supported in Raku.

The Raku ecosystem has a module P5chomp which exports a chomp function that mimics the original Perl behavior as much as possible.

chop §

As with chomp, in Raku, this returns the chopped string, rather than chopping in place. I. e. $x = "howdy";$y = chop($x); results in $x being "howdy" and $y being "howd". Also works as a method: $y = $x.chop.

Note that chop() (without arguments) is not supported in Raku.

The Raku ecosystem has a module P5chomp which exports a chop function that mimics the original Perl behavior as much as possible.

.head2 chown

chown is not in Raku.

chr §

Similar to the Perl version, coerces the target to an integer, and uses that as a Unicode code point to return the relevant character. Can be used as a function and a method:

chr(65); # "A" 
65.chr;  # "A"

Note that chr() (without arguments) is not supported in Raku.

The Raku ecosystem has a module P5chr which exports a chr function that mimics the original Perl behavior as much as possible.

chroot §

chroot is not in Raku.

close §

As in Perl, closes a filehandle. Returns a Boolean value. Both close $fh and $fh.close will work.

Note that close() (without arguments) is not supported in Raku.

closedir §

Not supported in Raku.

The Raku ecosystem has a module P5opendir which exports a closedir function that mimics the original Perl behavior as much as possible.

connect §

Use connect from IO::Socket::Async for an asynchronous socket or create a IO::Socket::INET socket for a synchronous one.

continue §

Instead of a continue block, you should use a NEXT block. The closest analog to a bare continue; in Perl appears to be proceed/succeed.

cos §

Works as in Perl.

cos also operates on $_ in the absence of a value, but not as a function, and as a method you need to call it as .cos rather than simply cos.

The Raku ecosystem has a module P5math which exports a cos function that mimics the original Perl behavior as much as possible.

crypt §

Not available in Raku.

The Raku ecosystem has a module P5math which exports a crypt function that mimics the original Perl behavior as much as possible.

dbm functions §

These functions have largely been superseded in Perl, and are unlikely to ever turn up in Raku (although any assumptions about the Raku database implementation may be premature).

defined §

Probably does what you expect, but technically it returns False on the type object, and True otherwise. This may make more sense when you realize that $num.raku is the type Any if you haven't assigned anything to it, and the assigned value if you have. Can, of course be used as a method: $num.defined. And any newly created class can have its own .defined method, thereby deciding how and when it should be considered undefined.

Note that defined() (without arguments) is not supported in Raku.

The Raku ecosystem has a module P5defined which exports a defined function that mimics the original Perl behavior as much as possible.

delete §

Raku replaces this with the new adverb syntax, specifically the :delete adverb. E. g. my $deleted_value = %hash{$key}:delete; and my $deleted_value = @array[$i]:delete;.

die §

Works similarly to the Perl version, but Raku's Exception mechanism may give you more power and flexibility than is available in Perl. See exceptions. To omit the stacktrace and location, like Perl's die "...\n", use:

note "...";
exit 1;

do §

Similar to the Perl version. Note that there must be a space between the do and the block.

Has been replaced in Raku by EVALFILE.

dump §

According to S29, dump has been... dumped.

each §

There is no exact equivalent, but you can use %hash.kv which returns a list of keys and values. For example: for %hash.kv -> $k, $v { say "$k: $v" }

Incidentally, what we have there with the -> is called a pointy block and, though there are a number of examples in the documentation, there doesn't seem to be a really clear explanation of how they work. https://design.raku.org/S04.html#The_for_statement may be of some help here, as well as the design document at https://design.raku.org/S06.html#%22Pointy_blocks%22. There is also some information at https://en.wikibooks.org/wiki/Perl_6_Programming/Blocks_and_Closures#Pointy_Blocks

The Raku ecosystem has a module P5each which exports an each function that mimics the original Perl behavior as much as possible.

eof §

In Raku, this is not usable as a function, but only as a method. I. e. $filehandle.eof. Returns True if at end of file.

eval §

The closest replacement is the EVAL function. However, this function has to be allowed explicitly using a pragma to work in the same way. Note that EVAL does not do any exception handling!

evalbytes §

No equivalent.

exec §

Nothing in Raku exactly replicates the Perl exec. shell and run are similar to Perl's system, but exec's behavior of not returning after executing a system command would have to be emulated by something like shell($command);exit(); or possibly exit shell($command);.

Neither of these workarounds have the behavior (on Unix-like systems) of replacing your Perl program's process with the new program; notably, they will not work for the practice in some long-running daemons of periodically redoing exec on themselves to reset their state or force operating-system cleanup. Nor will they serve exec's function of returning stale resources to the operating system.

If you want exec for these behaviors, you can use an exec* function via the NativeCall interface. Consult your operating system manual pages for exec (or other similarly-named calls such as execl, execv, execvp, or execvpe). (Beware: these calls are not generally portable between Unix-like operating system families.) Given those caveats, the Raku ecosystem Native::Exec module exports an exec function for Unix-like systems.

exists §

In Raku, this is not a function, but an adverb:

%hash{$key}:exists;
@array[$i]:exists;

exit §

Appears to do the same thing as in Perl.

exp §

Same as in Perl.

exp also operates on $_ in the absence of a value, but not as a function, and as a method you need to call it as .exp rather than simply exp.

The Raku ecosystem has a module P5math which exports an exp function that mimics the original Perl behavior as much as possible.

fc §

Looks like it does the same thing as in Perl except that calling it without arguments is not supported in Raku.

The Raku ecosystem has a module P5fc which exports a fc function that mimics the original Perl behavior as much as possible.

fcntl §

Appears not to be in Raku.

__FILE__ §

Replaced by $?FILE which is slightly different from __FILE__ in that it is always an absolute path, rather than a relative one in the Perl case.

The Raku ecosystem has a module P5__FILE__ which exports a __FILE__ term that mimics the original Perl behavior as much as possible.

fileno §

The native-descriptor method on IO::Handle returns the equivalent of fileno.

The Raku ecosystem has a module P5fileno which exports a fileno function that mimics the original Perl behavior as much as possible.

flock §

Currently unimplemented.

fork §

There is no built-in fork function. While it's possible to call it using NativeCall, it's highly unlikely that the resulting process will be usable.

Raku provides extensive support for, and internally uses, threads. However, fork only clones the thread that called fork, resulting in a process that will be missing its other threads, which will have been in unknown states and probably holding locks. Even if a Raku program doesn't knowingly start any threads, the compiler may create some of its own in the process of precompilation, and the VMs that Raku runs on also create their own internal worker threads for doing things like optimization and GC in the background. Thus, the presence of threads is pretty much assured, and there's no reasonable way to make fork reliably work in this case.

formats §

Raku does not have built-in formats.

getc §

Reads a single character from the input stream as in Perl. May now also be used as a method: $filehandle.getc

getpeername §

S29 lists it, but the implementation does not seem clear or, for that matter, implemented.

getpgrp §

Will not be implemented.

The Raku ecosystem has a module P5getpriority which exports a getpgrp function that mimics the original Perl behavior as much as possible.

getppid §

Will not be implemented.

The Raku ecosystem has a module P5getpriority which exports a getppid function that mimics the original Perl behavior as much as possible.

getpriority §

Will not be implemented.

The Raku ecosystem has a module P5getpriority which exports a getpriority function that mimics the original Perl behavior as much as possible.

get and set functions §

The Raku ecosystem has a module P5getpwnam which exports the endpwent, getlogin, getpwent, getpwnam, getpwuid and setpwent functions that mimic the original Perl behavior as much as possible.

The Raku ecosystem has a module P5getgrnam which exports the endgrent, getgrent, getgrgid, getgrnam and setgrent functions that mimic the original Perl behavior as much as possible.

The Raku ecosystem has a module P5getnetbyname which exports the endnetent, getnetent, getnetbyaddr, getnetbyname and setnetent functions that mimic the original Perl behavior as much as possible.

The Raku ecosystem has a module P5getservbyname which exports the endservent, getservent, getservbyname, getservbyport and setservent functions that mimic the original Perl behavior as much as possible.

The Raku ecosystem has a module P5getprotobyname which exports the endprotoent, getprotoent, getprotobyname, getprotobynumber and setprotoent functions that mimic the original Perl behavior as much as possible.

[NEEDS FURTHER RESEARCH] Apparently this range of functions are to be handled by roles like User, Group, etc.

getsock* §

[NEEDS FURTHER RESEARCH] These are likely implemented by some kind of IO::Socket object, but details are unclear.

glob §

Not available in core, although some of the functionality is offered by dir routine and its test argument.

See IO::Glob module in ecosystem

gmtime §

Like the various parts of localtime, gmtime's functionality appears to in the DateTime object. To get a UTC version of a DateTime object for the current time, for instance, use my $gmtime = DateTime.now.utc.

The Raku ecosystem has a module P5localtime which exports a gmtime function that mimics the original Perl behavior as much as possible.

goto §

The syntax for goto LABEL is already accepted, but the runtime part of goto is not yet implemented. So this will result in a runtime error:

FOO: goto FOO; # Label.goto() not yet implemented. Sorry.

grep §

Still in Raku, with the caveat that the block form now requires a comma after the block. I.e. @foo = grep { $_ = "bars" }, @baz. Can also be used as a method: @foo = @bar.grep(/^f/)

hex §

In Raku an expression must be specified.

Replaced by the adverbial form :16. E. g. :16("aF") returns 175. This is Str->Int.

The opposite result can be achieved (Int->Str) by using the .base method: 0xaF.base(10)

It just so happens that .Str defaults to base 10, so if you just say 0xaF, that will also print 175, but that may not be immediately obvious, so may not be the best way to go for this.

The Raku ecosystem has a module P5hex which exports a hex function that mimics the original Perl behavior as much as possible.

import §

Was never a builtin function in Perl in the first place. In Raku, typically, one declares functions as exportable or not, and all the exportable ones are exported. Nevertheless, selective importing is possible, but beyond the scope of this document. For details, see this section.

index §

Works as in Perl. Can also now be used as a method: "howdy!".index("how"); # 0. Main difference with Perl is that Nil is returned instead of -1 when the substring is not found. This is very useful in combination with the with command:

with index("foo","o") -> $index {
    say "Found it at $index";
}
else {
    say "Not found"
}

The Raku ecosystem has a module P5index which exports an index function that mimics the original Perl behavior as much as possible.

int §

There is a truncate function in Raku (also usable as a method) that does what Perl's int does. You may want to use that as a direct translation of Perl code, but in Raku, you can just as easily call the .Int method on the number. 3.9.Int; # 3 and 3.9.truncate are equivalent.

Please note that int does have a meaning in Raku. It is type that can be used to indicate a native integer:

my int $a = 42;   # a native integer, similar to Perl's integer values

int also operates on $_ in the absence of a value, but not as a function, and as a method you need to call it as .int rather than simply int.

The Raku ecosystem has a module P5math which exports an int function that mimics the original Perl behavior as much as possible.

ioctl §

Currently unimplemented in Raku.

join §

Works as in Perl, and also works as a method: @x.join(",")

keys §

Works as in Perl, and can also be used as a method: %hash.keys

kill §

No pre-defined core alternative exists. A non-portable method can be to use NativeCall:

use NativeCall;
sub kill(int32, int32) is native {*};
kill $*PID, 9; # OUTPUT: «Killed␤»

To kill processes that were started by creating a Proc::Async, use Proc::Async.kill method.

last §

Same as in Perl.

lc §

Works as in Perl, and also as a method: "UGH".lc. In Raku an expression must be specified.

The Raku ecosystem has a module P5lc which exports an lc function that mimics the original Perl behavior as much as possible.

lcfirst §

Does not exist in Raku.

The Raku ecosystem has a module P5lcfirst which exports an lcfirst function that mimics the original Perl behavior as much as possible.

length §

Replaced by chars, typically used as a method ($string.chars), but also works as a function.

The Raku ecosystem has a module P5length which exports an length function that mimics the original Perl behavior as much as possible.

__LINE__ §

Replaced by $?LINE.

The Raku ecosystem has a module P5__FILE__ which exports a __LINE__ term that mimics the original Perl behavior as much as possible.

link §

See link

listen §

Not clearly documented, but it appears that listen will be a method you would call on some variety of IO::Socket object.

local §

The Raku equivalent is temp. Unlike local, however, the value of the given variable is not immediately unset: it retains its original value until assigned to.

localtime §

Most of the functionality of localtime is found in DateTime. The specific parts of localtime can be found as follows:

my $d = DateTime.now;
my $sec  = $d.second; # Potentially includes fractional seconds 
my $min  = $d.minute;
my $hour = $d.hour;
my $mday = $d.day-of-month; # or $d.day; 1..31 
my $mon  = $d.month; # 1..12 
my $year = $d.year;
my $wday = $d.day-of-week; # 1 => Monday, 2 => Tuesday, etc. 
my $yday = $d.day-of-year; # 1..366 

Please note that ranges are not 0-based in Raku, as shown in the comments in the example.

There does not currently appear to be a way to get Perl's $isdst. Also, the result of scalar(localtime) that Perl provides is not available. $d.Str will give something along the lines of "2015-06-29T12:49:31-04:00".

The Raku ecosystem has a module P5localtime which exports a localtime function that mimics the original Perl behavior as much as possible.

lock §

There currently is no equivalent for this In Raku. There is a Lock class for creating a Lock object, that can be locked/unlocked as needed. But such a lock does not refer to any external objects.

log §

Same as in Perl.

log also operates on $_ in the absence of a value, but not as a function, and as a method you need to call it as .log rather than simply log.

The Raku ecosystem has a module P5math which exports a log function that mimics the original Perl behavior as much as possible.

lstat §

Likely implemented somewhere in one of the IO classes in Raku, but it is not clear where at this time.

m// §

Regular expression syntax is somewhat different in Raku, but the match operator still exists. If you're trying to rewrite some Perl code, the most important difference is that =~ is replaced by the smartmatch operator, ~~. Similarly, !~ is replaced by !~~. Options for regex operators are adverbs and are complicated. For details, see Adverbs

map §

As a function, the only difference between Perl and Raku is that, if you're using a block, the block must be followed by a comma. Can also be used as a method: @new = @old.map: { $_ * 2 }

mkdir §

Works as in Perl. When giving a multi-level directory specification, it will automatically create non-existing intermediate directories with the same MASK (similar to what "make_path" does of the File::Path module in Perl).

The zero argument (implicit $_) version is not permitted in Raku.

msg* §

Not builtins in Raku. May appear in an external module at some point. Maybe.

my §

Works as in Perl.

next §

The same in Raku.

no §

In Raku, this is usable for pragmas such as strict, but not for modules or versions.

oct §

Replaced by the adverbial form :8. E. g. :8("100") returns 64.

If you want to deal with strings that start in 0x, 0o, or 0b, you can just use the prefix:<+> operator.

The Raku ecosystem has a module P5hex which exports an oct function that mimics the original Perl behavior as much as possible.

open §

The most obvious change from Perl is the file mode syntax. To open a file for reading only, you would say open("file", :r). For write- only, read-write, and append, you would use :w, :rw, and :a respectively. There are also options for encoding and how the filehandle deals with newlines. Details here.

Another important change is that filehandles don't get automatically closed on scope exit. It's necessary to call close explicitly.

opendir §

No replacement. See &dir/IO::Path.dir for alternatives.

The Raku ecosystem has a module P5opendir which exports an opendir function that mimics the original Perl behavior as much as possible.

ord §

Same as in Perl. May be used as a method: "howdy!".ord; # 104

Note that ord() (without arguments) is not supported in Raku.

The Raku ecosystem has a module P5chr which exports a ord function that mimics the original Perl behavior as much as possible.

our §

The same in Raku.

pack §

Available in Raku when use experimental :pack has been specified in the scope where pack needs to be called. The template options are currently more restricted than they are in Perl. The current documented list can be found at unpack.

The Raku ecosystem has a module P5pack which exports a pack function that mimics the original Perl behavior as much as possible and which has a bigger set of supported features than the experimental Raku version.

package §

S10 indicates that package can be used in Raku, but only with a block. I. e. package Foo { ... } means that the code within the block would be in package Foo. There is a special case where a declaration of the form package Foo; as the first statement in a file indicates that the rest of the file is Perl code, but the usefulness of this is unclear. In fact, as modules and classes are declared with distinct keywords (such as class), it's unlikely you will use package directly in Raku.

__PACKAGE__ §

Replaced by $?PACKAGE which is slightly different from __PACKAGE__ in that it is the actual package object. You should call the .^name method on it to get a string.

The Raku ecosystem has a module P5__FILE__ which exports a __PACKAGE__ term that mimics the original Perl behavior as much as possible.

pipe §

Depending on your needs, see Channel to shuttle data between threads (and Concurrency tutorial for other options), or see Proc type for piping to and from processes.

pop §

Works in Raku, and can also be used as a method. I. e. my $x = pop @a; and my $x = @a.pop; are equivalent.

The non-parameter version of pop does not exist. Also, if the array is empty, a Failure will be returned in Raku, which will throw if the value is actually used in a significant way.

If you are using only defined values in your array, you can use the with function to handle this case:

with pop @array -> $popped {
    say "popped '$popped' of the array";
}
else {
    say "there was nothing to pop";
}

The Raku ecosystem has a module P5push which exports a pop function that mimics the original Perl behavior as much as possible.

pos §

Not available in Raku. The closest equivalent is the :c adverb, which defaults to $/.to if $/ is true, and 0 if it isn't. For information on :c, see Continue.

print §

print can be used as a function in Raku, writing to standard out. To use print as a function with a filehandle instead of standard out, you can use a method call: $fh.print("howdy!")

The Raku ecosystem has a module P5print which exports a print function that mimics the original Perl behavior as much as possible.

printf §

Raku version is similar; see sprintf for details on acceptable format directives. To print to a filehandle other than STDOUT, use the .printf method on that filehandle.

The Raku ecosystem has a module P5print which exports a printf function that mimics the original Perl behavior as much as possible.

prototype §

Not available in Raku. The closest equivalent is .signature. E. g. say &sprintf.signature results in "(Cool $format, *@args)".

push §

Works as in Perl, as well as being available as a method: @a.push("foo");. Note: the flattening behavior is different in Raku: @b.push: @a will push @a into @b as a single element. See also the append method.

Also note that push in Raku returns the array to which was pushed, contrary to Perl where it returns the new number of elements.

The Raku ecosystem has a module P5push which exports a push function that mimics the original Perl behavior as much as possible.

quoting §

These survive the transition to Raku. Some notes:

q/.../;  # is still equivalent to using single quotes.
qq/.../; # is still equivalent to using double quotes.
qw/.../; # is more commonly written as <...> in Raku.

There are some added quoting constructs and equivalents, as explained at quoting.

Has been replaced by rx/.../.

No direct equivalent, i.e. nothing that just returns the string with all the ASCII non-word characters backslashed. In regexes, however, using $foo will treat $foo as a literal string, and using <$foo> will interpret the contents of $foo as regex code. Note that the angle brackets are doing something different here than they do outside a regex. For more information on this, see https://design.raku.org/S05.html#Extensible_metasyntax_(%3C...%3E)

The Raku ecosystem has a module P5quotemeta which exports a quotemeta function that mimics the original Perl behavior as much as possible.

rand §

rand by itself works as it does in Perl, but you can no longer give it an argument. You can, however, use it as a method on a number to get that behavior. I. e. the Perl rand(100) is equivalent to 100.rand in Raku. Additionally, you can get a random integer by using something like (^100).pick. For why you are able to do that, see ^ operator and pick.

The Raku ecosystem has a module P5math which exports a rand function that mimics the original Perl behavior as much as possible.

read §

read is found in IO::Handle and IO::Socket in Raku. It reads the specified number of bytes (rather than characters) from the relevant handle or socket. The use of an offset available in Perl is not documented to exist at this time.

readdir §

Not a builtin function. To iterate through the contents of a directory, take a look at dir routine.

The Raku ecosystem has a module P5opendir which exports a readdir function that mimics the original Perl behavior as much as possible.

readline §

Not available in Raku. You most likely want to use the .lines method in some way. For more detailed information on reading from files, see io.

readlink §

Appears to be gone from Raku. There is a method resolve in IO::Path that will follow symlinks if the OS / Filesystem supports them.

The Raku ecosystem has a module P5readlink which exports a readlink function that mimics the original Perl behavior as much as possible.

readpipe §

Doesn't appear to be working in Raku, but qx// is functional, so it might be lurking around in some class that isn't obvious.

recv §

Appears to be in IO::Socket. Not extensively documented at this time.

redo §

Unchanged in Raku.

ref §

Gone. To quote S29, "If you really want the type name, you can use $var.WHAT.^name.

The Raku ecosystem has a module P5ref which exports a ref function that mimics the original Perl behavior as much as possible.

rename §

Still available in Raku.

requires §

No equivalent.

reset §

No equivalent.

The Raku ecosystem has a module P5reset which exports a reset function that mimics the original Perl behavior as much as possible.

return §

Appears to be available in Raku, although not clearly documented.

reverse §

In Raku, this only reverses the elements of a list. reverse(@a) or @a.reverse. To reverse the characters in a string, use the .flip method.

reverse without parameters is not supported in Raku.

The Raku ecosystem has a module P5reverse which exports a reverse function that mimics the original Perl behavior as much as possible.

rewinddir §

Not supported in Raku.

The Raku ecosystem has a module P5opendir which exports a rewinddir function that mimics the original Perl behavior as much as possible.

rindex §

Works as in Perl, and may also be used as a method. E. g. $x = "babaganush";say $x.rindex("a"); say $x.rindex("a", 3); # 5, 3. Main difference with Perl is that Nil is returned instead of -1 when the substring is not found. This is very useful in combination with the with command:

with index("foo","o") -> $index {
    say "Found it at $index";
}
else {
    say "Not found"
}

The Raku ecosystem has a module P5index which exports a rindex function that mimics the original Perl behavior as much as possible.

rmdir §

Works in Raku and can also be used as a method. rmdir "Foo"; and "Foo".IO.rmdir; are equivalent.

s/// §

Regular expression syntax is somewhat different in Raku, but the substitution operator exists. If you're trying to rewrite some Perl code, the most important difference is that =~ is replaced by the smartmatch operator, ~~. Similarly, !~ is !~~. Options for regex operators are adverbs and are complicated. For details, see Adverbs page

say §

say can be used as a function, defaulting to standard out. To use say as a function with a filehandle instead of standard out, you need to put a colon after the filehandle. I. e. say $fh: "Howdy!". The use of the colon as an "invocant marker" here is discussed at https://design.raku.org/S03.html#line_4019. Alternately, you can use a method call: $fh.say("howdy!")

The Raku ecosystem has a module P5print which exports a say function that mimics the original Perl behavior as much as possible.

scalar §

Gone. Apparently "very" gone.

Some functions of the modules created for the CPAN Butterfly Plan accept a :scalar named parameter to indicate that the scalar behavior of the function is required.

seek §

Not documented in any real way yet, but listed as a method of the IO::Handle class.

The Raku ecosystem has a module P5seek which exports a seek function that mimics the original Perl behavior as much as possible.

seekdir §

Not supported in Raku.

The Raku ecosystem has a module P5opendir which exports a seekdir function that mimics the original Perl behavior as much as possible.

select §

"[S]elect as a global concept is dead." When I asked around about select, I was told that $*OUT and such are overridable in dynamic scope, and that IO::Capture::Simple (at https://github.com/sergot/IO-Capture-Simple) may be of use for something you might be doing with the value of select.

semctl §

No longer in core.

semget §

No longer in core.

semop §

No longer in core.

send §

Can be found in the IO::Socket class.

setpgrp §

Will not be implemented.

The Raku ecosystem has a module P5getpriority which exports a setpgrp function that mimics the original Perl behavior as much as possible.

setpriority §

Will not be implemented.

The Raku ecosystem has a module P5getpriority which exports a setpriority function that mimics the original Perl behavior as much as possible.

setsockopt §

Not documented, but probably hiding in an IO class somewhere.

shift §

Works in Raku, and can also be used as a method. I. e. my $x = shift @a; and my $x = @a.shift; are equivalent.

The non-parameter version of shift does not exist. Also, if the array is empty, a Failure will be returned in Raku, which will throw if the value is actually used in a significant way.

If you are using only defined values in your array, you can use the with function to handle this case:

with shift @array -> $shifted {
    say "shifted '$shifted' of the array";
}
else {
    say "there was nothing to shift";
}

The Raku ecosystem has a module P5shift which exports a shift function that mimics the original Perl behavior as much as possible.

shm* §

Gone from the core. May turn up in a module somewhere.

shutdown §

Not documented, but likely moved into IO::Socket.

sin §

Same as in Perl.

sin also operates on $_ in the absence of a value, but not as a function, and as a method you need to call it as .sin rather than simply sin.

The Raku ecosystem has a module P5math which exports a sin function that mimics the original Perl behavior as much as possible.

sleep §

Still works as in Perl, but is not limited to integer values for seconds. And it always returns Nil.

If you're interested in the return values of sleep to ensure sleeping until a specified time, then you should use sleep-until in Raku (which takes an Instant).

If you're interested in running some code every N seconds, and you don't care on which thread it runs, you should probably use react and whenever with a Supply.interval.

The Raku ecosystem has a module P5sleep which exports a sleep function that mimics the original Perl behavior as much as possible.

sockets §

Not currently documented, but will likely wind up in IO::Socket.

sort §

sort exists in Raku, but is somewhat different. $a and $b are no longer special (see Special Variables) and sort routines no longer return positive integers, negative integers, or 0, but rather Order::Less, Order::Same, or Order::More objects. See sort for details. May also be used as a method I. e. sort(@a) is equivalent to @a.sort.

splice §

Available in Raku. Can also be used as a method. splice(@foo, 2, 3, <M N O P>); is equivalent to @foo.splice(2, 3, <M N O P>); .

split §

Works mostly as in Perl. There are some exceptions, though. To get the special behavior of using the empty string, you must actually use the empty string - the special case of the empty pattern // being treated as the empty string does not apply. If you use a regex for the split, it will use the regex, while a literal string will be treated literally. If you wish to have the delimiters included in the resulting list, you need to use the named parameter :all, like this: split(';', "a;b;c", :all) # a ; b ; c Empty chunks are not removed from the result list as they are in Perl. For that behavior, see comb. Details on split are here. Unsurprisingly, split also now works as a method: "a;b;c".split(';')

split now requires a pattern. For the equivalent of Perl's behavior of splitting on whitespace when no pattern is specified, use words (or use split with /\s+/ as the pattern and :skip-empty as a named argument).

sprintf §

Works as in Perl. The formats currently available are:

Compatibility:

Perl (non-)compatibility:

There are modifiers for integers, but they're mainly no-ops, as the semantics aren't settled:

sqrt §

Same as in Perl.

sqrt also operates on $_ in the absence of a value, but not as a function, and as a method you need to call it as .sqrt rather than simply sqrt.

The Raku ecosystem has a module P5math which exports a sqrt function that mimics the original Perl behavior as much as possible.

srand §

Available in Raku.

stat §

Unlikely to be implemented as a built in function since it's POSIX specific, but available through the NativeCall interface.

state §

Available in Raku, see state.

study §

study is no more.

The Raku ecosystem has a module P5study which exports a study function that mimics the original Perl behavior as much as possible.

sub §

Unsurprisingly, we still have subroutines! You can have a signature in your subroutine which allows you to specify arguments. Nevertheless, in the absence of a signature (and only in the absence of a signature), @_ still contains what is passed to the function. So, in theory, you don't need to change that aspect of a function if porting from Perl to Raku (although you should probably consider the option of using a signature). For all the gory details, see functions.

__SUB__ §

Replaced by &?ROUTINE which is slightly different from __SUB__ in that it is the actual Sub (or Method) object. You should call the .name method on it to get a string.

The Raku ecosystem has a module P5__FILE__ which exports a __SUB__ term that mimics the original Perl behavior as much as possible.

substr §

See substr-rw.

Can be used as a function or a method. Can't be used on Str literals, as they are immutable.

    my $a = 'Cheesy';
    $a.substr-rw(4,1)="k"; # returns 'k' 
    say $a; # OUTPUT: «Cheeky␤» 
 
    substr-rw($a, 0, 3) = "Lea";
    say $a; # OUTPUT: «Leaky␤» 

See substr.

Can be used as a function or a method. substr("hola!", 1, 3) and "hola!".substr(1, 3) both return "ola".

symlink §

See symlink.

syscall §

Not a builtin in Raku. Most likely out in a module somewhere, but it's currently unclear where.

sys* §

As with the non-sys versions of these functions, are probably lurking in the IO classes somewhere.

system §

For this, you probably want (run) or (shell routine).

syswrite §

As with sysopen and friends, this has moved into the IO classes.

tell §

As a method on IO::Handle.

telldir §

Not supported in Raku.

The Raku ecosystem has a module P5opendir which exports a telldir function that mimics the original Perl behavior as much as possible.

tie §

The Raku alternative to tying a scalar, is the Proxy container. For example:

sub lval() {
  Proxy.new(
    FETCH => method () { ...},
    STORE => method ($new) { ... }
  )
}

This makes lval a left-value sub. Whenever the value is requested, the FETCH method is called. And whenever it is used in an assignment, the STORE method is called.

For arrays and hashes (objects that do the Positional and/or Associative role), one only needs to provide the methods that these roles require to get the functionality that tie provides in Perl. These are documented in the Subscripts section.

The Raku ecosystem has a module P5tie which exports tie / tied functions that mimics the original Perl behavior as much as possible.

time §

Number of seconds since epoch (as an Int), same as in Perl.

times §

Not available in Raku.

The Raku ecosystem has a module P5times which exports a times function that mimics the original Perl behavior as much as possible.

tr/// §

Works similarly to how it does in Perl. The one caveat is that ranges are specified differently. Instead of using a range "a-z", you would use "a..z", i.e. with Perl's range operator. In Raku, tr/// has a method version, called trans, which offers a few additional features.

Perl's /r flag is instead implemented as TR/// operator. The y/// equivalent does not exist.

truncate §

Not currently implemented (2018.04).

uc §

Works as a function and a method. uc("ha") and "ha".uc both return "HA". There is no support for the parameterless version.

The Raku ecosystem has a module P5lc which exports a uc function that mimics the original Perl behavior as much as possible.

ucfirst §

Raku has done away with ucfirst. The title case function tc or tclc probably does what you need; in the first case, it does "title case", which might correspond to different characters in different alphabets; it defaults to upper case if there's no title case mapping. On the other hand, tclc applies tc and then puts the rest of the characters in lower case.

The Raku ecosystem has a module P5lcfirst which exports a ucfirst function that mimics the original Perl behavior as much as possible.

undef §

There is no undef in Raku. You can't undefine a function, and the closest equivalent value is probably Nil, but you'll likely have no use for that.

If you were using something like (undef, $file, $line) = caller;, you would just get the filename and line number directly in Raku instead of discarding the first result of caller. caller has been replaced by callframe in Raku, so the equivalent statement would be ($file, $line) = callframe.annotations<file line>;

The Raku ecosystem has a module P5defined which exports an undef function that mimics the original Perl behavior as much as possible.

unlink §

Still available. Usable as a method: "filename".IO.unlink

The zero argument (implicit $_) version of unlink is not available in Raku.

unpack §

Available in Raku when use experimental :pack has been specified in the scope where unpack needs to be called. The template options are currently more restricted than they are in Perl. The current documented list can be found at unpack.

The Raku ecosystem has a module P5pack which exports an unpack function that mimics the original Perl behavior as much as possible and which has a bigger set of supported features than the experimental Raku version.

unshift §

Works as in Perl, as well as being available as a method: @a.unshift("foo");. Note: the flattening behavior is different in Raku: @b.unshift: @a will unshift @a into @b as a single element. See also the prepend method.

Also note that unshift in Raku returns the array to which was pushed, contrary to Perl where it returns the new number of elements.

The Raku ecosystem has a module P5shift which exports an unshift function that mimics the original Perl behavior as much as possible.

untie §

Not supported in Raku, but see tie for the whole story.

The Raku ecosystem has a module P5tie which exports an untie function that mimics the original Perl behavior as much as possible.

use §

In Perl, this requires a minimum version of the perl executable in order to run. In Raku, this requires a version of the specification, (e.g. 6.c), which can be implemented by various Raku executables.

utime §

No equivalent.

values §

Available in Raku. Can also be used as a method. values %hash is equivalent to %hash.values.

vec §

There is no support for vec() in Raku.

S29 says "Should replace vec with declared buffer/array of bit, uint2, uint4, etc." Support for bit, uint2, uint4 has not landed yet. But support for uint8, int8, uint16, int16, uint32, int32, uint64, int64 as well as the system sized uint and int have landed. In scalar forms, as well as in array and shaped array (aka matrix) forms.

wait §

[NEEDS FURTHER RESEARCH] Unclear where this has gone. There's a wait method in Supply, and an await method in both Channel and Promise. Which, if any or all, of these is a direct equivalent of Perl's wait is unclear.

waitpid §

As with wait, the disposition of this is unclear.

wantarray §

There is no wantarray in Raku; however, there are very easy ways to cover many of the use cases which wantarray filled.

First, since Raku does not need special reference syntax to contain a List or Array in a Scalar, simply returning a list may be all that is needed:

sub listofstuff {
    return 1, 2, 3;
}
my $a = listofstuff();
print $a;                      # prints "123" 
print join("<", listofstuff()) # prints "1<2<3"

One of the most common use cases is to provide either an array of lines or elements, or a prettier string than would be produced by simply printing the array. One can mix in a custom .Str method for this purpose:

sub prettylist(*@origlist) {
    @origlist but role {
        method Str { self.join("<") }
    }
}
print prettylist(1, 2, 3);  # prints "1<2<3" 
print join(">", prettylist(3, 2, 1)); # prints "3>2>1"

In the above example, the returned list may be lazy, and the .Str method is not called until stringification happens, so no extra work is done to generate something which is not asked for.

Another use case is to create methods which are mutators when called in void context but produce copies during assignment. It is generally considered better form in Raku not to do so, even more so because void context does not exist in Raku, with the closest equivalent being sink context, since users can quite easily turn any copy-producing method into a mutator using the .= operator:

my $a = "foo\n";
$a.ords.say; # says "(102 111 111 10)" 
$a .= chomp;
$a.ords.say; # says "(102 111 111)"

However if you have your heart set on using the same function name for both operations, you can get most of the way there by mixing in a .sink method, which will be called when the result finds itself in sink context. There are some caveats however, so again, this is not advised:

multi sub increment($b is rw) {
    ($b + 1) does role { method sink { $b++ } }
}
multi sub increment($b) {
    $b + 1
}
my $a = 1;
increment($a);
say $a;                 # says "2" 
my $b = increment($a);
say $a, $b;             # says "2 3" 
# ...users will just have to be aware that they should not accidentally 
# sink a stored value later, though this requires some effort to 
# actually do: 
sub identity($c is rw) { $c };
$a = 1;
$b = increment($a);
identity($b);
$a.say;                  # says "2"

warn §

warn throws a resumable exception. To simply print a message to $*ERR, you would use the note function. For more on exceptions, see Exceptions.

write §

Formats are gone from Raku, so this no longer works.

y/// §

This synonym for tr/// is gone. For functionality, see the entry for tr///.