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description=Raku with grammars, multiple dispatch, lazy lists and exact rationals — run by Raku++ in a browser tab, from a 3 ms command line, or compiled to a standalone binary.;

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Text of the page (random words):
mple com port 8080 limits timeout 30 retries 3 config for ini parse config section s say s name s pair map _ key _ value join sequences that never end the operator continues a sequence from the pattern you started and lists are lazy so an infinite one costs nothing until you ask it for a piece my powers 1 2 4 say powers 10 say 1 grep is prime 8 my triangular 1 running sums of an endless list say triangular 8 decimals that add up 0 1 0 2 0 3 is true decimal literals are kept as exact rationals rather than binary floating point so money and measurements behave the way you were taught they would say 0 1 0 2 0 3 say 1 3 nude numerator and denominator exactly say 1 3 1 6 say 2 3 raku one value that is several values a junction holds many values at once and collapses to a single answer when you compare against it no loop no grep no boolean bookkeeping my n 42 say so n any 3 42 100 say so n all 1 2 3 say so camelia all a e l operators that operate on operators folds an operator across a list keeps the running results applies one to every element they are built out of ordinary operators rather than being special cases so they work with the ones you define yourself my r 1 2 4 8 say r reduce with say r 2 apply to each say r running totals say 1 5 map 2 characters the way a reader counts them a string is a sequence of graphemes not bytes and not code points so an accented letter and a family emoji each count as the one character you can see the character database is in the language too names in both directions properties numeric values and unicode script classes usable straight from a regex say zoë chars graphemes not bytes or code points say chars one family one character say ß fc eq ss fc real case folding say π uniname say so ωμέγα script greek and roles phasers custom operators with their own precedence native types a bignum tower promises and channels nativecall into c the tour walks through them in about an hour the specification is the reference the party trick interpreters all the way down the playground s dropdown carries five complete interpreters for other languages each one written in raku pick the python one put a python program in the standard input box and press run what answers you in a second or so is three interpreters stacked on top of each other inside a browser tab with no server anywhere in the picture fizzbuzz py your python program typed into the input box is parsed and executed by python raku a python 3 interpreter 1 487 lines of raku which is itself parsed and executed by raku a raku interpreter written in c 17 compiled ahead of time to webassembly running in the tab you are reading this in with no server behind it showcase written in raku interprets lisp 432 lines a scheme subset closures and an exact numeric tower included forth 223 lines forth a stack machine and a word dictionary perl 1 644 lines perl 5 with its own regex engine python 1 487 lines python 3 off side rule and all javascript 2 167 lines javascript and typescript classes and closures included every name above is a link it opens the playground with that interpreter loaded and a program already in the input box and runs it the five are projects in the showcase each with a page of its own the grammar the evaluator and where its edges are run a python program on it they are not toys built to look good on a landing page each one is a mid size program that exercises a different corner of raku grammars and a tree walking evaluator a full precedence ladder sigil variables and context an indent dedent tokenizer and each was written partly to find bugs in raku which it duly did the long version with where every millisecond goes interpreters all the way down the numbers what it costs to run cold start is under 4 ms interpreted and 2 9 ms as a compiled binary say hello process start included because there is no vm to bring up first after that the same program can be interpreted or compiled with exe and what compiling is worth depends on what the program spends its time doing 2 4 at most nothing measurable on three of the eighteen benchmarks and three run faster interpreted the interpreter compiles some shapes itself as it runs a sub of integer arithmetic and a loop over int str num and rat variables and plain arrays and hashes which is why its tight loop its hashes its given when and its recursion below are within a few milliseconds of the binary best of six runs process start included lower is better benchmark interpreted compiled speed up string building 4 3 ms 3 4 ms 1 3 hashes 7 5 ms 7 3 ms 1 0 tight loop 5 2 ms 3 2 ms 1 6 given when 6 4 ms 3 3 ms 1 9 regex 27 8 ms 18 0 ms 1 5 naive recursion 13 9 ms 5 8 ms 2 4 appending to a string with appends in place in every mode so building a large string is linear rather than quadratic work the browser engine is the same interpreter again and lands within 1 3 6 8 of the native interpreter on these kernels all seventeen benchmarks beside rakudo and mutsu same machine same sitting and the method benchmarks md every kernel release over release on all four engines plus what the o optimizer adds on top the performance dashboard more than one core threads that actually use them start and await promises supplies channels and react whenever the same shapes as the reference implementation since v3 0 0 worker threads use every core by default independent work runs at once with no env var to remember rakupp_gil 1 is the escape hatch back to the cooperative global lock n independent workers nothing shared between them the method page s own kernel sub work seed my int s 0 my int x seed for m x x 1103515245 12345 2147483647 s s x 7 s my r await n map start work _ n workers n units of work plain loop one thread n start blocks speed up 1 61 ms 72 ms 0 85 2 123 ms 74 ms 1 66 4 250 ms 77 ms 3 25 8 491 ms 137 ms 3 58 each row does n units of 300 000 iterations so the work doubles from row to row the plain loop s time doubles with it and a start column that stays flat is the speed up a contention free fan out measured with no env var this is the shipping default under rakupp_gil 1 every row sits at 0 98 1 00 timed from inside the program with now on an apple m3 4 performance 4 efficiency cores 2026 10 07 one start block is a loss 0 85 because interpreted code runs about 15 slower on every thread while any worker is live four workers on the four performance cores give 3 25 and eight half of them on the slower efficiency cores only a tenth more change the shape and the number changes with it four threads incrementing one shared atomicint finish at 0 76 slower than one thread doing all the work while a counter per worker gives 3 13 and a loop that raku compiles in a plain run but not while other threads are live loses to its own plain loop 0 38 until its routine takes its inputs as parameters and is compiled whole 3 76 that is why the method page insists you report the thread count beside the ratio and the threads faq has the short answers this is also the one section here you cannot try in the editors above a browser tab runs the interpreter single threaded without a start hyper for and hyper hand a block to the worker threads in batches and a hyper operator over plain numbers runs as a native loop split over the cores the same work four ways one computation four forms all four give the same list my a 1_000_000 map num my m a map _ 3 sqrt one thread in order my h a hyper map _ 3 sqrt the block on worker threads my f hyper for a _ 3 sqrt the loop on worker threads my o a 3 sqrt a native loop over the cores form time against map map 322 ms 1 0 hyper map 162 ms 2 0 hyper for 90 ms 3 6 a 3 sqrt 24 ms 13 a million nums median of three runs on the same m3 2026 10 09 map keeps to one thread because it promises order hyper map calls the block afresh for each element where hyper for keeps one scope per worker the operator form is no interpreted code at all int and num lists under the comparisons sqrt and the other numeric methods run natively on several cores from 32 768 elements and anything else takes the element by element path with the same answer the hyper faq has which form to reach for and when each one loses what you can build with it servers not just scripts asynchronous sockets are in the box io socket async for clients and servers signal for a shutdown that closes cleanly and tls through io socket async ssl when the system has an openssl to talk to a server is a react block a tcp echo server whole save it run it leave it running react whenever io socket async listen 127 0 0 1 15480 conn whenever conn supply bin data await conn write echo encode data conn close then from another terminal talk to it with nc printf hello nc 127 0 0 1 15480 echo hello each of these is a real program in the repository and each compiles to a standalone binary with exe the tiles open each project s page in the showcase how to run it a live session how it works with the source one click further a pastebin an http server written straight onto raw sockets no framework underneath no framework needed open its page a static file server rakus point it at a folder open a browser it is what this site is developed against locally open its page a chat server many clients at once one thread each driven from as many terminals as you care to open open its page a key value store redis shaped with its own text protocol on tcp the can it hold a connection open and talk test open its page a markdown converter a grammar with an actions class that emits html as it parses markdown in a styled page out open its page a distribution inspector seventeen ecosystem distributions doing the work dependency graphs validation reports open its page all of them with what each one is meant to prove the showcase the networking guide clients servers graceful shutdown https is networking md what else is in the binary it is a toolchain not just a runtime a linter a syntax highlighter an ast dump a profiler and a native compiler in the one executable with no plugins to install and nothing to configure every transcript below is real output from this version lint ten rules before it runs at all rakupp lint app raku app raku 2 warning n is declared but never used unused variable app raku 3 warning condition is a constant the branch always runs constant condition app raku 4 note return as the final statement is redundant the block s last value is returned automatically redundant return rakupp lint 2 warnings 1 note in app raku eight warnings and two advisory notes deliberately built to under report rather than cry wolf faced with eval or a symbolic reference a rule switches itself off rather than guess warnings exit non zero so ci can gate on it notes do not highlight the highlighter this page is using rakupp highlight ansi e my x 42 say x is x my x 42 say x is x rakupp highlight html e my x 42 say x is x div class highlight pre span span span class k my span span class nv x span span class mi 42 span span class nb say span span class s x is x span pre div the terminal form paints straight in as above the html form emits standard pygments classes so it drops into a stylesheet you already have the same highlighter colours this site the course and compiled to webassembly along with everything else the editors on this page live as you type into them ast what it made of your program rakupp ast e say 1 2 3 program call say binary intlit 1 binary intlit 2 intlit 3 for answering did it parse that the way i meant without a debugger c checks the syntax without running anything and cpp prints the c that exe would compile add o to read the optimized codegen instead exe one file 10 mb 2 5 ms to start rakupp exe hello raku o hello compiled native hello raku hello ls lh hello rwxr xr x 9 8m hello about a second to compile and the size barely moves with the program a 46 line mandelbrot and a 106 line json grammar both come out at 9 9m because what dominates is the runtime linked in beside them the machine that runs the result needs nothing installed not even raku also in there profile which prints a routine level wall time profile after the run or json for a tool to read bundle and aot which produce standalone binaries that carry the interpreter rather than replacing it target js which writes the program as javascript for node or a browser and the perl one liner family n p a i bak which cluster the way you expect cli md is the full list the install page has the short one parse once precompiled modules and programs raku can cache the parsed form of what it runs so the next run does not re read and re parse text that has not changed it is off until you ask nothing is written to your disk before then and it comes as two switches rather than one because the two halves are worth very different amounts two switches and the two that tell you what is going on rakupp precomp modules on cache the parse of the modules you use rakupp precomp files on cache the program s own parse rakupp precomp info what is on where it lives what it holds rakupp precomp clean empty it always safe modules worth it immediately a dependency tree is a lot of source and none of it changes between runs if you turn on one switch turn on this one though the margin is narrower than it once was so measure your own program if the difference matters use xml 10 files 1 110 lines start up no cache 6 0 ms cached 4 8 ms programs only the big ones a script s own parse is already sub millisecond and a small program s floor is process start up not parsing it pays from about a thousand lines up bare file saved 50 lines 0 1 ms 1 000 lines 1 5 ms 20 000 lines 32 3 ms across the 22 fastest programs in examples 12 to 106 lines each turning the file cache on made no measurable difference at all and the run that writes an entry pays for it that asymmetry is why these are two switches one is nearly always right the other is a judgement about your own program both settings persist and what is stored is the parse not your source caching md has the method what invalidates an entry and how to look inside it take one home install it one binary no runtime to install beside it no package manager required if you would rather not use one one command macos linux the bsds curl fssl https raku online install sh sh windows in powershell irm https raku online install windows ps1 iex or on windows don t type anything download the installer a wizard with an add remove programs entry no root no administrator a per user prefix on your path with rakupp upgrade to keep it current homebrew guix nix and every archive then run something a file a one liner or standard input rakupp program raku rakupp e say 1 100 grep is prime sum rakupp ne say if error server log task shaped answers in the faq self contained archives for macos universal linux x86 64 and arm64 static openbsd x86 64 and windows x64 static crt are on the releases page there are also guix and nix channels and it builds from source with cmake and any c 17 compiler no third party libraries that includes linux on ri...