Esoteric, Obfuscated, Artistic Programming in Ruby Yusuke Endoh (@mametter) Cookpad Inc. Bath Ruby Conference 2018 (2018/03/23)

And Now for Something Completely Different — in Ruby Yusuke Endoh (@mametter) Cookpad Inc. Bath Ruby Conference 2018 (2018/03/23)

Yusuke Endoh (@mametter) • MRI committer – Was the release manager for 2.0 – Implemented coverage.so, keyword arguments, etc. • Branch coverage (Ruby 2.5) • Working at Cookpad Inc. – Cookpad employs two full-time Ruby committers (Koichi Sasada and me)

• A recipe sharing platform service – Monthly Average Users: 90 million – https://cookpad.com/uk PR: Cookpad Inc.

• A recipe sharing platform service – Monthly Average Users: 90 million – https://cookpad.com/uk PR: Cookpad Inc. We're hiring! HQ is in Bristol Aim to be No.1 in 100 countries (Now in 22 Languages and 68 Countries)

Today's Topic • "Completely different" Ruby programs – Ruby can do anything! • Agenda – 1. Ruby with limited letters – 2. Funny, self-descriptive Ruby programs

1. RUBY WITH LIMITED LETTERS

A Ruby program require "1234567890" 164494982952174876928097944808592 345203368399394864831728762954025 223544083864187912864887414172728 297936126807895282322033562499828 91940559064073941914244494205218

Demo • "Hello, world!" program by using only numbers – You can encode not only Hello world, but also any Ruby programs $ ruby H3110.rb Hello, Bath & Bristol Ruby! $ Hello world only by numbers

Internal • Gödel numbering • Ruby's black magic Hello world only by numbers

Internal: Gödel numbering • A technique to encode any given string to a natural number – In: a byte array 𝑛1 , 𝑛2 , 𝑛3 , 𝑛4 , 𝑛5 , … – Out:2𝑛1 × 3𝑛2 × 5𝑛3 × 7𝑛4 × 11𝑛5 × ⋯ – To decode it, use prime factorization • The gem uses much easier way – Encoding: str.unpack("H*")[0].hex – Decoding: [num.to_s(16)].pack("H*") Hello world only by numbers

Internal: Ruby's black magic • How to get the number – It is just placed at the toplevel of code • My answer: – ObjectSpace.each_object(Integer) • Unsure if this is portable, but it works anyway – Try to decode all enumerated integers, identify the desired Ruby code, and eval – See the source code (32 lines) in detail • https://github.com/mame/1234567890 Hello world only by numbers

How to install Hello world only by numbers $ gem install 1234567890_ Don't forget underscore! (rubygems.org required at least one letter)

Hello world only by "_" require "_" ____ _ _____ ____ __ ____ ____ __ ___ ____ __ __ _ ______ _____ ___ _ _ ___ _____ ______ ____ _ _ ____ _ _ ____ _ ____ __ __ ___ _ ______ ___ __ ______ _ ___ _____ __ ____ __ ___ ___ ______ ___ _ ______ ___ __ _ ___ _ ______ ___ __ ______ _ ____ __ _ ___ ______ ____ ____ __ __ ____ __ ___ ____ _ ____ ____ _ _ _ ______ ___ ___ __ _____ ____ __ ____ ___ _____ ___ ____ ___ __ _ ______ ____ _ ______ _____

Demo • "Hello, world!" program written using only underscores $ ruby __hello__.rb Hello, Bath & Bristol Ruby! $ Hello world only by "_"

Internal: Base-6 • Encode the Gödel number in Base-6 • Represent each digit with underscores – Use length (n+1) for digit n • Why base-6 is chosen? – To minimize the expected code length: log𝑏 126 × ൗ 𝑏 2 + 1 + 1 Hello world only by "_" 304313… ____ _ _____ ____ __ ____ …

You can install $ gem install _ Hello world only by "_"

Summary • Ruby beats letter limitation • More? – See my RubyConf 2017 talk begin begin begin public begin begin def each clear rescue begin begin begin end end end concat begin dup ensure concat begin clear concat concat concat concat concat concat size concat begin begin begin size end end end begin size end ensure begin clear end end end concat begin dup ensure concat begin clear begin concat concat size end until hex concat concat concat concat begin size end concat concat begin size end rescue upcase begin concat begin concat size end end begin size end ensure begin clear end end end concat begin dup ensure concat begin clear concat begin concat size end unless begin end begin concat concat concat begin size end end @_="_"=~/$/;_=@_+@_;$><<(""<<(_*_*_+@_)*_*_*_<< ((_+@_)*_*_*_+@_)*_*_+@_<<(((_+@_)*_*_+@_)*_+@_ )*_ *_ << ( ( (_+@_ )*_*_+ @_) * _+ + @_) * _*_ <<((((+ _+@_)*_ * _+ + +@_ )*_+@_)* _++ @_ )* _ ++@_ <<((_*_+@_ )*_ + + + @_)* _*_ <<_*_*_*_* _<< ( (_ * _ +@_) *_*_*_++@_ )*_<<(((_++@_)*_+@_)*_*_+@_)*_*_+@_<<((_+@_)*_* _*_*_ +@_)* _<<( ( (_+ +@_ )*_ ++ @_ ) *_+ @_) *_*_*_+ @_<< ( _* _ *_*_*_++ @_) *_+@_<< (((( _ ++ + +@_)* _*_ ++ @_ )* _ +@_)*_++ @_)*_ +@_<< (((( _+ + @_)*_*_+ @_)*_+@_)*_+@_)*_<<(((_+@_)*_*_*_+@_)*_+@_)*_<< _*_*_*_*_+@_<<(_*_+@_)*_)#_$`/^|:()[_-|?|_||:`/ Only symbols Only alphabets

2. FUNNY, SELF-DESCRIPTIVE RUBY PROGRAMS

Self-descriptive ??? eval(s=s= %w@proc{| n|z=32.ch r;k="[#{n +=1}]";u= ":>==;<==?"[m=n**4 %-15,m+13]||"#{$f= k}";d="Y.E.#{c=64. chr}*'')";$f||d<23&&m[-9,9 ]=d;puts(m)}}[1]#pY.E.@*'')

Self-descriptive FizzBuzz eval(s=s= %w@proc{| n|z=32.ch r;k="[#{n +=1}]";u= ":>==;<==?"[m=n**4 %-15,m+13]||"#{$f= k}";d="Y.E.#{c=64. chr}*'')";$f||d<23&&m[-9,9 ]=d;puts(m)}}[1]#pY.E.@*'') eval(s=s=%w@proc{|n|z=32.ch r;k="[#{n+=1}]";u=":>==;<== ?"[m=n**4%-15,m+13]||"#{$f= k}";d="Y.E.#{c=64.chr}*'')" ;$f||d<2 3&&m[-9,9 ]=d;puts( m)}}[2]#p roc{|n|z= 32.chr;k="[#{n+=1}]";u=":>= =;<==?"[m=n**4%-15,m+13]||" #{$f=k}";d="Y.E.#{c=64.chr} *'')";$f||d<==;<== ?"[m=n**4%-15,m+13]||"#{$f= k}";d="Y.E.#{c=64.chr}*'')" ;$f||d<23&&m[-9,9 ]=d;puts(m)}}#proc {|n|z=32. chr;k="[# {n+=1}]";u=":>==;< ==?"[m=n**4%-15,m+ 13]||"#{$f=k}";d="Y.E.#{c=6 4.chr}*'' )";$f||d< 23&&m[-9 ,9]=d;put s(m)}}pro c{|n|z=32 .chr;k="[ #{n+=1}]" ;u=":>==; <==?"[m=n **4%-15,m +13]||"#{ $f=k}";d= "Y.E.#{c= 64.chr}*' ')";$f||d <23&&m[-9,9]=d;pu ts(m)}}proc{|n|z=3 2.chr;k=" [#{n+=1}] ";u=":>==;<==?"[m= n**4%-15,Y.E.@*'') [3]

Internal • Reconstruct self • Reshape itself as the next number – Embedded font data – Fizzbuzz – Shaping • Output the result • Make it "executable ASCII-art" Self-descriptive FizzBuzz eval(s=s= %w@proc{| n|z=32.ch r;k="[#{n +=1}]";u= ":>==;<==?"[m=n**4 %-15,m+13]||"#{$f= k}";d="Y.E.#{c=64. chr}*'')";$f||d<23&&m[-9,9 ]=d;puts(m)}}[1]#pY.E.@*'')

Quine • A program that outputs itself • Trick – Step 1. Reconstruct self as a string – Step 2. Print it • Additional step makes Quine "funny" eval s="puts('eval s='+s.inspect)" Self-descriptive FizzBuzz

Embedded font data Self-descriptive FizzBuzz • Original data (165 bytes) • Replace spaces with "0", and "#" with "1" • Interpret each line as binary number (50 bytes) • Shorten them by to_s(36) (35 bytes) ### ## ### ### # # ### ### ### ### ### ### ## # # # # # # # # # # # # # # # # # # ## # # # ### ### ### ### ### # ### ### ### ## # # # # # # # # # # # # # # # # # # # ### ### ### ### # ### ### # ### ### # ## # ## 111 110 111 111 101 111 111 111 111 111 111 110 0 00 101 010 001 001 101 100 100 001 101 101 100 101 1 11 101 010 111 111 111 111 111 010 111 111 111 110 0 01 101 010 100 001 001 001 101 010 101 001 100 101 1 10 111 111 111 111 001 111 111 010 111 111 100 110 1 11 1073733623,2905756245,1063256021,2371130133,1063231487 0hr9u5z, 1c20fv9, 0hl19lh, 137pjpx, 0hl0qnz

Executable ASCII-art • Write a code with no space and backslash • Wrap it with "eval(%w(" and ").join)" • You can shape your code as you like puts"Hello,world!" eval(%w(puts"Hello,world!").join) eval(%w(pu ls "H el lo ,w or ld!")*"")# #=> Hello,world!

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Quine-relay • A Ruby code • that generates Rust code • that generates Scala code • … • that generates REXX code • that generates the original Ruby code 128 languages involved in total Quine-relay

Quine-relay • A Ruby code • that generates Rust code • that generates Scala code • … • that generates REXX code • that generates the original Ruby code 128 languages involved in total Quine-relay

Demo https://travis-ci.org/mame/quine-relay Quine-relay

Internal – Step 1. Reconstruct self as a string – Step 2. Wrap Python's Hello world – Step 3. Print it Quine-relay eval s="puts( 'eval s='+s.dump )" Ruby's Quine print( "Hello!" ) + Python's Hello world eval s="puts('print('+('eval s='+s.dump).dump+')')" ↓ RubyPython Quine

Internal • In theory: Repeat this process for 127 languages • In practical: The naïve approach explodes the size of intermediate code – To avoid this problem, it uses many tricks • compression algorithm • on-time code generation • etc. – See the generator in detail https://github.com/mame/quine-relay/blob/master/src/code-gen.rb Quine-relay

Monumental Quine A column object 3D model data Ruby code is inscribed You can buy it at Shapeways! https://www.shapeways.com/shops/mametter Execute the code 3D printer

Internal • The shorter is code, the cheaper ☺ – 3D printing fee: $15 per one line – The code does not contain complex-glyph letters ("3", "8", "g") to omit them from font data 33 eval(_=%[b='DEILMQTVY';eval((%[a=(-1)EE0.5;f=->EfVf.each_slice(2)Y;c=->wVz=->dVd.mapVd=d.rotate(1)YY ;Q=->k,l,mV((m-k)E(l-k).conT).arQ<0Y;y=[];x=0.99;o,T=w.partitionV|n|d=0;z[n].mapV|k,l|y<rVk,m,l=r;k=k[2],l,m[2];r[I]=Q[Ek]DDv.allMV|q|z[k].anyMV|k,l|q==k||Q[k,q,l]YYY;z[s].mapV| k,l,m|l[0,2]=k,m;n[l]Y;(s[I..-1].mapVt=t[1]until(t[I]);k,m=l=t;m[0],k[1]=t;n[m];n[t=k];lY<+TIEduE45u>mv%^Y=Vny-`zce)k`heIt%`Vzf;c2nk4d|Vp^D_,,|kDDL2r_sDy%%fiMV6cYE)5`,m/k YQ/;IEezMVv,QchILY|p%%i=4Q2(vwael61//-l67uQ;2Tq,c_'qEIcm1cL;i++2-tYdbenq%pxr;2'Vn (uDa)n)zf4w)%5vh;ssV5kI;)z;2=+ToeIeT9-(iM1s/mYQvEY`vMxu%Y0u5 7Qaoh2Ep+icop_u0%=-zv,omq`Qz/41DV'`f9L5`M'bVxx%/;qLtq12%q:V'9,fD,ovu%qr|+e+rudI`Ir0 5chVd+Q5`II76rY0laT%b(I>Y%EQ1xf^|r,1)%4--zQa'c5Dmd: 9-I15%Lp/>>z57^,Th2>%la0;5`dE1qy;f6)||Ikw_0wdMM5so7b..4qy`nQrz%Vf7Ii^epY(x=|49Lh(=>sI_sbofb7|qM,unaD%^i:|;_tEEnb-DDt`t%I2h;0x5f^yhs,pbLf+m^e>yqzQ '%::|^=,5-b=^_1x1se`kp,%wq4T%;'E.:Dsp_V-0||,)=;.a|<%0QY:;t:fEmk:4|_%o-.:aooq/6mThdvz4`uQqY1r'em.5'z1 2p7e%%pp6ebMM,m`5QpYx'd`,`6a4T)6Q.k.E.YsdiE^ox9pyrsr%|(kfn=y9q`6;=V%iie%)y-1i(y 'V-n^uTva%l0Q>,yz;E0:LbV'eTb6MIb``Da.__ihbacxY|fc6>pTtl;ivVt,q>/%w,=hnI+i90>10u59te,Ildw4p94x`iwvs`f +^)w1M>%wf^].bytesV|i|e=eE59+(i-5)%L9Y;Q=->iVk=e%i;e/=i;kY;d=VI2=>c[[]]Y;54.upto(1I0)V|h|d[h%L9+I7]= c[(0..Q[5]).mapVl=o=T=[];n=0;(-2..Q[17]).mapV[l=Q[2],o=Q[1I]+Q[21]Ea+1+a]Y.flat_mapV|m,n|E,(h,)=[[o, l],[(o+o=n)/2,0]][0..lDl=m]Y.mapV|o,l|n=l<1M((n==0ML:1).upto(L)V|k|T<fiz|'.tr('x%-|','%-'<<125)));' [[[ Monumental Quine (c) 2015 Yusuke Endoh -- tested with ruby 2.2.1 -- built on 2015/04/01 ]]]']) Embedded TrueType Font Data + Renderer Triangulation Algorithm for Font Polygons 3D Model Generator Monumental Quine

15 quzzle • An interactive Quine eval$s=%w[b=0 x4160ab7de523 f8c9;i=(m=0.. 15).find{|i|1 >b&m=15<<4*i} ;t=m|n=m<<4*o =("AdABrBlBAu A"=~/(.)#{ARG V*''}¥1/||04| |0)-4;(n<1||n >1<<64||[255< <12]&[t>>040| |___________9 |__________12 |___________8 |__________15 |0,t>>16,t]!= [])?t=0:i+=o; ;s="eval$s=%% w[b=0x%016x"% (b^=t.&b|m&b> >o*4)+$s.gsub (/(¥|_+¥d+)+/ ,'')[/;.*/]+" ]*''||0"<<92| |1;z=s=s.scan (/.{13}/);3.t imes{|j|s[(i| |___________3 |___________2 |___________5 |__________14 |0)/4*8+i+j*4 ,0]=m=(z=32.c hr)*13};c=b;4 .times{puts(( 0..3.times{pu ts((s.slice!( 0,4)*z).rstri p)}).map{j=c% 16;c/=16;;(0| |0)<(j)?"|"+j .to_s.rjust(1 2,"_"):m}*(z| |__________13 |___________7 |__________11 |__________10 |0),z)};b==0x fedcba9876543 21&&("%b"%"1t v7c1th0wylel7 3ba35knw3t".t o_i(36)).tr(" 01",".#").sca n(/.{25}/){pu ts$&}]*''||0¥ |___________6 |___________1 |___________4

Tiq-taq-toe • The world's first quine containing AI s="n=' '[0,2] d|=1<< $*[0]. to_i-1 ;m,i=[ f=proc {|b|a= [];[73 ,7,84, 273,56 ,146," proc{| t|[t*= "",s].map{|u|u.gsub!(35.chr,"")};d=0000000;eval(s+t)}[ %w(448,292].find{|m|b&m==m}?1:9.times{|i|b&(513<>9|b<<9][0],i]}&&a.min||0}][0][d];s='s= "'+s.s plit*' '+'"pr oc{|t| [t*="" ,s].ma p{|u|u .gsub! (35.ch r,"")} ;d=0%0 6o;eva l(s+t) }[%%w( '%d|=$*[0]?0:512<6?s.slice!(0,54):(0..4).map{|x|x&1>0?(i+=3;s.s lice!(0,6)):62[y]<1?n*7:n+(y*5-5...y*5).map{|j|1105[j- 7]<1&& d[i]|d [i+9]> 0&&~j& 5981[j /2]^d[ i]>0?3 5.chr* 2:n;}* ""+n}* "")}|| __(C). YEndoh 2009)]

qng and qif  qng – A png image file containing Ruby code that produces this image  qif – A gif version

Lipogram Quine format= %%->{#({#){#.{#0{#1{#2{#3{#4{#5{#6{#7{#8{#9{#h{#k{#l{#p{#v{#w{#<{#*{#a{#b{#c{#d{#e{#f{; t=->s,x,y{->&u{u[s,x,y]}[&:tr]};z="!-{";->&u{u[y="().0123456789hklpvw<*abcdef¥¥",t["m~i",",-~", "$-{"]+t["$",z,"i-{"],t[t["YQUO@g=`@W='@ABCDEFGHIJKLMNOPQRSTUVWXYZ';g=^YQUO@g=`@^+g+^AA^;Y=?=;n =Y+OoWUO_Q UriUVOYsTY+Y;x=- >s{sBVyt Ys};q,=n[u =^ZormUt^]?@u =ZormUtA?[ DC,TFEBBDEI]-x[u +?`]:x[W +?`]-x[y]: n=~/=Z?o?r?m? U?t?=/?x[u ]-x[$&]:Y;z='ZormUt= C``->{H{Dt=- >s,x,y {Js,x, y]}[&: tr]};z=^!-{ ^;Jy=^I^,t [^m~iK,-~K$-{^]+t[^$ ^,z,^i-{^],t [t[^EK C^+$/, ^^],^G ^,t[^qntuz| yKm-|^,z]+ t[^;jmnrxy>,K&-{K$-{ ^]+t[^o;tK/- {^,z]] ]}[&Jt [^xjsi K&-{^,z]]}[ &:to_sym]] }[]`;DYQUO^@YQUO@@`R ``SS`R`F`T`` `ABPUW N@``MT `AAA^' BgsuV@/[C-L ]/A{[FEBWM r,$/,gBtr@'`^'+W,j=L IBWMrSSLGSSI GSSGHSSL CA,TgB unPUWN@^MT^ A,j,?#+WBW MUrsT^{#^,W+LEBWMrTE ,^->&u{u[^,' ^,^'][YQ UO$&]} ;GGBtimYs{| y|Print@@@ CBBLGABmUP{|x|^qZXzm uDHjtVOCuVnO ooCYHWIJyrnonDmE GtijRU oNFxGWXxuOm CmIEYRXsgZ EgqOKQMGHJOKQnYuuVYy IrCEmrPqVgno irYDnnxLDjZWCGyN nZmnIy zKXignRYPnz DuCYgMHyyM JjqWYD ODruUPCm DtqFqFDCrrJVxXJzOg MWQGNnUuio^Bt o_i@FIA[x/ E-D+@y +DA/ETGI ]>C?@FEBWMrA:@z[C] ==$/||!z[C]?? ;:zBsOiWY!@C,DAA}T^^+$/ABtr@@!$T[C]&&q||CABWMr,^^AA;z[C]==$/&&z[C]=^^};Yxit;;;;;;;AA"," "+$/,"" ],"`^@-Z",t["qntuz|y","m-|",z]+t[";jmnrxy>,","&-{","$-{"]+t["o;t","/-{",z]]]}[&->&u{u[t["xjsi", "&-{",z]]}[&:to_sym]]}[]%;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; eval"(eval((%w%%<<%w%566716c68276d3528236d3728292e20313233343536373839386b6c6076777c3a216263646 566672b376d322566716c68276d3528222b276b222929222b356d3f3d3b3e6d356b2c6f63616c6f5671627961626c65 637a256b256b387d3d2e337b737e22697475637d7b317c2d3e6b557d32266f627d6164722d5f38257d366f627d61647 92f3b51303c2a23323e2e2132363d5d287b557b2f352d5a387b536b2f352d5d287b597d5a3e6d3e7f2d366f3f6f327f 3d6f316f347f3d3f2f387b557d5d287b54262d5a356b3a7d37266f627d61647d3035252d2e3b753b71347d3d2e337c2 87c297b77337c287c297d5d7b562a34727d5d7b3a7d32212d2b722b37397d3226322c247b522d6e79683c2d2e78342d 2b722d5b247b5224222c2a7c22296d2b722d5c247b547b52223830322b242f2c22222d5c2224322c247b52217e64757 a7c79783d6d2c7 22c2a7 d5b247b522b3 a6d6e62787 97e3c2 8362d2b7834 2d2b722d5b247b 522f6b 34783f2d2b72 2c2a7d5d5d 5d7b56 27347b52287 a637968362d2 b722c2a7d5d5d7 b562a3 47f6f537 97 d6d5d5d7 b5 d552b313566 716c62282566 716c6828252775 252c3c 35277523 35 2a252525 29 2e2071636b6 82525286a2 529292922272e276 375726 82f2b5 03d293 d5f292 b7b53323e23 68627c242f 2c276e2472782725 22272b 236c2a 6d3936 3e2368 627c3c39343 c3c36343c3 c343 53c3c3 930392 c2a276 e257e6 071636 b6 82 2286a22292c 2a6c2f332b 236e 236861 62737a 222b73 222c23 6b2932 3e 23 68627a223c2 22d2e36257 b757b5 22c272 22c22272d5 b55667 16 c6 4262d5d7b34 343e24796d 65637b 7c797c 7072796e64 782828 20 3e 2e2934392e2 d61607b7c787 c722 176646 a7d6 571353a6 4726c6 035726 e6c6f6 f6035653366 3739727e6f6e 613d 623434 796a 67716f6b 633874 336468 757c6d 603d6632356 77463776662376 17c683 678643 5373c6 8367e6 565757 265697 63270323d62 707172676e6f69 627561 3e6e68 79313a 666360 34397b 6e666d 6e66397a783 469676e6775607e6a71357035676865397978673a617365613c6132757160703d613471733173313032727732687467 3a7c67686366743b6e6165796f622e247f6f59682336392b587f223d213b28297b21392f223a24363d5e303f3823323 e236862792a382a7b503d5d3d342f2c7c712a7b503d5f3f3b3a3a7e237c6963656128203c2139292d7a22222b242f29 2e2472782821242a2b503d5626217c7c70392e2368627c222229292b3a7b503d5d3d342f26262a7b503d5d32222d7b3 56879647b3b3b3b3b3b3b39292%*%%%).pack(%%h*%)))";;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

Demo • Works as an ordinary Quine $ ruby lquine.rb > lquine2.rb $ diff –s lquine.rb lquine2.rb lquine.rb and lquine2.rb are identical Lipogram Quine

"a" is removed from the world! format= %%->{#({#){#.{#0{#1{#2{#3{#4{#5{#6{#7{#8{#9{#h{#k{#l{#p{#v{#w{#<{#*{#a{#b{#c{#d{#e{#f{; t=->s,x,y{->&u{u[s,x,y]}[&:tr]};z="!-{";->&u{u[y="().0123456789hklpvw<*abcdef¥¥",t["m~i",",-~", "$-{"]+t["$",z,"i-{"],t[t["YQUO@g=`@W='@ABCDEFGHIJKLMNOPQRSTUVWXYZ';g=^YQUO@g=`@^+g+^AA^;Y=?=;n =Y+OoWUO_Q UriUVOYsTY+Y;x=- >s{sBVyt Ys};q,=n[u =^ZormUt^]?@u =ZormUtA?[ DC,TFEBBDEI]-x[u +?`]:x[W +?`]-x[y]: n=~/=Z?o?r?m? U?t?=/?x[u ]-x[$&]:Y;z='ZormUt= C``->{H{Dt=- >s,x,y {Js,x, y]}[&: tr]};z=^!-{ ^;Jy=^I^,t [^m~iK,-~K$-{^]+t[^$ ^,z,^i-{^],t [t[^EK C^+$/, ^^],^G ^,t[^qntuz| yKm-|^,z]+ t[^;jmnrxy>,K&-{K$-{ ^]+t[^o;tK/- {^,z]] ]}[&Jt [^xjsi K&-{^,z]]}[ &:to_sym]] }[]`;DYQUO^@YQUO@@`R ``SS`R`F`T`` `ABPUW N@``MT `AAA^' BgsuV@/[C-L ]/A{[FEBWM r,$/,gBtr@'`^'+W,j=L IBWMrSSLGSSI GSSGHSSL CA,TgB unPUWN@^MT^ A,j,?#+WBW MUrsT^{#^,W+LEBWMrTE ,^->&u{u[^,' ^,^'][YQ UO$&]} ;GGBtimYs{| y|Print@@@ CBBLGABmUP{|x|^qZXzm uDHjtVOCuVnO ooCYHWIJyrnonDmE GtijRU oNFxGWXxuOm CmIEYRXsgZ EgqOKQMGHJOKQnYuuVYy IrCEmrPqVgno irYDnnxLDjZWCGyN nZmnIy zKXignRYPnz DuCYgMHyyM JjqWYD ODruUPCm DtqFqFDCrrJVxXJzOg MWQGNnUuio^Bt o_i@FIA[x/ E-D+@y +DA/ETGI ]>C?@FEBWMrA:@z[C] ==$/||!z[C]?? ;:zBsOiWY!@C,DAA}T^^+$/ABtr@@!$T[C]&&q||CABWMr,^^AA;z[C]==$/&&z[C]=^^};Yxit;;;;;;;AA"," "+$/,"" ],"`^@-Z",t["qntuz|y","m-|",z]+t[";jmnrxy>,","&-{","$-{"]+t["o;t","/-{",z]]]}[&->&u{u[t["xjsi", "&-{",z]]}[&:to_sym]]}[]%;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; eval"(eval((%w%%<<%w%566716c68276d3528236d3728292e20313233343536373839386b6c6076777c3a216263646 566672b376d322566716c68276d3528222b276b222929222b356d3f3d3b3e6d356b2c6f63616c6f5671627961626c65 637a256b256b387d3d2e337b737e22697475637d7b317c2d3e6b557d32266f627d6164722d5f38257d366f627d61647 92f3b51303c2a23323e2e2132363d5d287b557b2f352d5a387b536b2f352d5d287b597d5a3e6d3e7f2d366f3f6f327f 3d6f316f347f3d3f2f387b557d5d287b54262d5a356b3a7d37266f627d61647d3035252d2e3b753b71347d3d2e337c2 87c297b77337c287c297d5d7b562a34727d5d7b3a7d32212d2b722b37397d3226322c247b522d6e79683c2d2e78342d 2b722d5b247b5224222c2a7c22296d2b722d5c247b547b52223830322b242f2c22222d5c2224322c247b52217e64757 a7c79783d6d2c7 22c2a7 d5b247b522b3 a6d6e62787 97e3c2 8362d2b7834 2d2b722d5b247b 522f6b 34783f2d2b72 2c2a7d5d5d 5d7b56 27347b52287 a637968362d2 b722c2a7d5d5d7 b562a3 47f6f537 97 d6d5d5d7 b5 d552b313566 716c62282566 716c6828252775 252c3c 35277523 35 2a252525 29 2e2071636b6 82525286a2 529292922272e276 375726 82f2b5 03d293 d5f292 b7b53323e23 68627c242f 2c276e2472782725 22272b 236c2a 6d3936 3e2368 627c3c39343 c3c36343c3 c343 53c3c3 930392 c2a276 e257e6 071636 b6 82 2286a22292c 2a6c2f332b 236e 236861 62737a 222b73 222c23 6b2932 3e 23 68627a223c2 22d2e36257 b757b5 22c272 22c22272d5 b55667 16 c6 4262d5d7b34 343e24796d 65637b 7c797c 7072796e64 782828 20 3e 2e2934392e2 d61607b7c787 c722 176646 a7d6 571353a6 4726c6 035726 e6c6f6 f6035653366 3739727e6f6e 613d 623434 796a 67716f6b 633874 336468 757c6d 603d6632356 77463776662376 17c683 678643 5373c6 8367e6 565757 265697 63270323d62 707172676e6f69 627561 3e6e68 79313a 666360 34397b 6e666d 6e66397a783 469676e6775607e6a71357035676865397978673a617365613c6132757160703d613471733173313032727732687467 3a7c67686366743b6e6165796f622e247f6f59682336392b587f223d213b28297b21392f223a24363d5e303f3823323 e236862792a382a7b503d5d3d342f2c7c712a7b503d5f3f3b3a3a7e237c6963656128203c2139292d7a22222b242f29 2e2472782821242a2b503d5626217c7c70392e2368627c222229292b3a7b503d5d3d342f26262a7b503d5d32222d7b3 56879647b3b3b3b3b3b3b39292%*%%%).pack(%%h*%)))";;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; $ sed s/a//g lquine.rb Lipogram Quine

"" is removed from the world! formt= %%->{#({#){#.{#0{#1{#2{#3{#4{#5{#6{#7{#8{#9{#h{#k{#l{#p{#v{#w{#<{#*{#{#b{#c{#d{#e{#f{; t=->s,x,y{->&u{u[s,x,y]}[&:tr]};z="!-{";->&u{u[y="().0123456789hklpvw<*bcdef¥¥",t["m~i",",-~", "$-{"]+t["$",z,"i-{"],t[t["YQUO@g=`@W='@ABCDEFGHIJKLMNOPQRSTUVWXYZ';g=^YQUO@g=`@^+g+^AA^;Y=?=;n =Y+OoWUO_Q UriUVOYsTY+Y;x=- >s{sBVyt Ys};q,=n[u =^ZormUt^]?@u =ZormUtA?[ DC,TFEBBDEI]-x[u +?`]:x[W +?`]-x[y]: n=~/=Z?o?r?m? U?t?=/?x[u ]-x[$&]:Y;z='ZormUt= C``->{H{Dt=- >s,x,y {Js,x, y]}[&: tr]};z=^!-{ ^;Jy=^I^,t [^m~iK,-~K$-{^]+t[^$ ^,z,^i-{^],t [t[^EK C^+$/, ^^],^G ^,t[^qntuz| yKm-|^,z]+ t[^;jmnrxy>,K&-{K$-{ ^]+t[^o;tK/- {^,z]] ]}[&Jt [^xjsi K&-{^,z]]}[ &:to_sym]] }[]`;DYQUO^@YQUO@@`R ``SS`R`F`T`` `ABPUW N@``MT `AAA^' BgsuV@/[C-L ]/A{[FEBWM r,$/,gBtr@'`^'+W,j=L IBWMrSSLGSSI GSSGHSSL CA,TgB unPUWN@^MT^ A,j,?#+WBW MUrsT^{#^,W+LEBWMrTE ,^->&u{u[^,' ^,^'][YQ UO$&]} ;GGBtimYs{| y|Print@@@ CBBLGABmUP{|x|^qZXzm uDHjtVOCuVnO ooCYHWIJyrnonDmE GtijRU oNFxGWXxuOm CmIEYRXsgZ EgqOKQMGHJOKQnYuuVYy IrCEmrPqVgno irYDnnxLDjZWCGyN nZmnIy zKXignRYPnz DuCYgMHyyM JjqWYD ODruUPCm DtqFqFDCrrJVxXJzOg MWQGNnUuio^Bt o_i@FIA[x/ E-D+@y +DA/ETGI ]>C?@FEBWMrA:@z[C] ==$/||!z[C]?? ;:zBsOiWY!@C,DAA}T^^+$/ABtr@@!$T[C]&&q||CABWMr,^^AA;z[C]==$/&&z[C]=^^};Yxit;;;;;;;AA"," "+$/,"" ],"`^@-Z",t["qntuz|y","m-|",z]+t[";jmnrxy>,","&-{","$-{"]+t["o;t","/-{",z]]]}[&->&u{u[t["xjsi", "&-{",z]]}[&:to_sym]]}[]%;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; evl"(evl((%w%%<<%w%566716c68276d3528236d3728292e20313233343536373839386b6c6076777c3216263646 566672b376d322566716c68276d3528222b276b222929222b356d3f3d3b3e6d356b2c6f63616c6f5671627961626c65 637256b256b387d3d2e337b737e22697475637d7b317c2d3e6b557d32266f627d6164722d5f38257d366f627d61647 92f3b51303c223323e2e2132363d5d287b557b2f352d5387b536b2f352d5d287b597d53e6d3e7f2d366f3f6f327f 3d6f316f347f3d3f2f387b557d5d287b54262d5356b37d37266f627d61647d3035252d2e3b753b71347d3d2e337c2 87c297b77337c287c297d5d7b56234727d5d7b37d32212d2b722b37397d3226322c247b522d6e79683c2d2e78342d 2b722d5b247b5224222c27c22296d2b722d5c247b547b52223830322b242f2c22222d5c2224322c247b52217e64757 7c79783d6d2c7 22c27 d5b247b522b3 6d6e62787 97e3c2 8362d2b7834 2d2b722d5b247b 522f6b 34783f2d2b72 2c27d5d5d 5d7b56 27347b52287 637968362d2 b722c27d5d5d7 b5623 47f6f537 97 d6d5d5d7 b5 d552b313566 716c62282566 716c6828252775 252c3c 35277523 35 2252525 29 2e2071636b6 825252862 529292922272e276 375726 82f2b5 03d293 d5f292 b7b53323e23 68627c242f 2c276e2472782725 22272b 236c2 6d3936 3e2368 627c3c39343 c3c36343c3 c343 53c3c3 930392 c2276 e257e6 071636 b6 82 228622292c 26c2f332b 236e 236861 62737 222b73 222c23 6b2932 3e 23 68627223c2 22d2e36257 b757b5 22c272 22c22272d5 b55667 16 c6 4262d5d7b34 343e24796d 65637b 7c797c 7072796e64 782828 20 3e 2e2934392e2 d61607b7c787 c722 176646 7d6 5713536 4726c6 035726 e6c6f6 f6035653366 3739727e6f6e 613d 623434 796 67716f6b 633874 336468 757c6d 603d6632356 77463776662376 17c683 678643 5373c6 8367e6 565757 265697 63270323d62 707172676e6f69 627561 3e6e68 79313 666360 34397b 6e666d 6e66397783 469676e6775607e671357035676865397978673617365613c6132757160703d613471733173313032727732687467 37c67686366743b6e6165796f622e247f6f59682336392b587f223d213b28297b21392f22324363d5e303f3823323 e2368627923827b503d5d3d342f2c7c7127b503d5f3f3b337e237c6963656128203c2139292d722222b242f29 2e24727828212422b503d5626217c7c70392e2368627c222229292b37b503d5d3d342f262627b503d5d32222d7b3 56879647b3b3b3b3b3b3b39292%*%%%).pck(%%h*%)))";;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; $ sed s/a//g lquine.rb Lipogram Quine

Demo • You can delete any one letter • It automatically restore itself! $ sed s/a//g lquine.rb > broken.rb $ ruby broken.rb > broken2.rb $ diff –s broken.rb broken2.rb broken.rb and broken2.rb are identical Lipogram Quine

Internal • Main trick: – This code executes code2 • The string literal is just ignored • If "a" is removed: – This code executes code1 and terminates Lipogram Quine "#a{ code1;exit }"; code2 "#{ code1;exit }"; code2 String interpolation!

Internal • Basic structure: Lipogram Quine "#a{#b{#c{… A code without "a","b","c",… exit }" A code with only "a","b","c",…

More? Read my book! • "The World of Obfuscated, Esoteric, Artistic Programming" – Contains about 40 codes like this talk – Written in Japanese

Related contests • International Obfuscated C Code Contest (IOCCC) – A programming contest for hard-to-read programs written in C language • Transcendental Ruby Imbroglio Contest for rubyKaigi (TRICK) – The judges (including I) held TRICK twice – TRICK FINAL is now open (~ 2018/03/31) • https://github.com/tric/trick2018 • Winners will be awarded at RubyKaigi 2018

Conclusion • Ruby is incredibly flexible – You can use Ruby with broken keyboards (only numbers, or only underscores) – You can write artistic and super-robust Quine in Ruby • Ruby Programming is fun – Even without practicality – If you like practicality, join  • One more thing…

A Quine for Bath Ruby Conference "#a{#b{#c{…