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#REDIRECT [[Perl#Community]]
{{short description|Frivolous Perl program}}
{{multiple issues|
{{notablity|date=December 2021}}
{{Self-published|date=April 2020}}
}}
'''Just another Perl hacker''', or '''JAPH''', typically refers to a [[Perl]] program that prints "Just another Perl hacker," (the comma is canonical but is occasionally omitted). Short JAPH programs are often used as [[signature block|signatures]] in online [[Internet forum|forums]], or as [[T-shirt]] designs. The phrase or acronym is also occasionally used (without [[Computer programming|code]]) for a signature.

JAPH programs are classically done using extremely [[obfuscated code|obfuscated]] methods, in the spirit of the [[International Obfuscated C Code Contest|Obfuscated C Contest]]. More recently, as the phenomenon has become well-known, the phrase is sometimes used in ordinary examples (without obfuscation).

The idea of using tiny Perl programs that print a signature ''as a signature'' was originated by [[Randal L. Schwartz]], in his postings to the [[newsgroup]] comp.lang.perl.<ref>Randal L. Schwartz in [[Usenet]] message [email protected] explaining the origin of JAPH. Available through [http://groups.google.com/group/comp.lang.perl.misc/msg/ecc405feeefc120c Google.com]</ref> He wrote many of the JAPHs which are shown below.

==Examples==

JAPH program without obfuscation:

<syntaxhighlight lang="perl">
print "Just another Perl hacker,";
</syntaxhighlight>

Embedding JAPH in opaque code:

<syntaxhighlight lang="perl">
$_='987;s/^(\d+)/$1-1/e;$1?eval:print"Just another Perl hacker,"';eval;
</syntaxhighlight>

Decoding JAPH from a transposed [[string literal]]:

<syntaxhighlight lang="perl">
$_="krJhruaesrltre c a cnP,ohet";$_.=$1,print$2while s/(..)(.)//;
</syntaxhighlight>

Printing out JAPH as separate processes:
<syntaxhighlight lang="perl">
for $i (0..4) {
if (!fork) {
$i == 0 or not { $SIG{INT} = sub { print "J" } } or
$i == 1 or not { $SIG{INT} = sub { print "A" } } or
$i == 2 or not { $SIG{INT} = sub { print "P" } } or
$i == 3 or not { $SIG{INT} = sub { print "H" } } ;
sleep $i;
last;
}
}

kill INT => $$;
</syntaxhighlight>

Appearing as if it does something completely unrelated to printing JAPH:

<syntaxhighlight lang="perl">
$_ = "wftedskaebjgdpjgidbsmnjgc";
tr/a-z/oh, turtleneck Phrase Jar!/; print;
</syntaxhighlight>

Forking processes to print out one letter each in the correct order:<ref>[http://perl.plover.com/obfuscated/ Plover.com]</ref>
<syntaxhighlight lang="perl">
@P=split//,".URRUU\c8R";@d=split//,"\nrekcah xinU / lreP rehtona tsuJ";sub p{
@p{"r$p","u$p"}=(P,P);pipe"r$p","u$p";++$p;($q*=2)+=$f=!fork;map{$P=$P[$f^ord
($p{$_})&6];$p{$_}=/ ^$P/ix?$P:close$_}keys%p}p;p;p;p;p;map{$p{$_}=~/^[P.]/&&
close$_}%p;wait until$?;map{/^r/&&<$_>}%p;$_=$d[$q];sleep rand(2)if/\S/;print
</syntaxhighlight>

Using only Perl [[Keyword (computer programming)|keywords]] (no [[punctuation]]):<ref>Originally posted at [http://www.perlmonks.org/?node_id=290607 perlmonks.org] by user blokhead</ref>

<syntaxhighlight lang="perl6">
not exp log srand xor s qq qx xor
s x x length uc ord and print chr
ord for qw q join use sub tied qx
xor eval xor print qq q q xor int
eval lc q m cos and print chr ord
for qw y abs ne open tied hex exp
ref y m xor scalar srand print qq
q q xor int eval lc qq y sqrt cos
and print chr ord for qw x printf
each return local x y or print qq
s s and eval q s undef or oct xor
time xor ref print chr int ord lc
foreach qw y hex alarm chdir kill
exec return y s gt sin sort split
</syntaxhighlight>

Using only [[punctuation]], no [[alphanumeric]] characters. This breaks after Perl 5.30.0, as using $# and $* create fatal errors. This JAPH was written by [https://metacpan.org/author/ROODE Eric Roode] and only works on [[Unix]] and [[Unix-like]] systems:

<syntaxhighlight lang="perl">
`$=`;$_=\%!;($_)=/(.)/;$==++$|;($.,$/,$,,$\,$",$;,$^,$#,$~,$*,$:,@%)=(
$!=~/(.)(.).(.)(.)(.)(.)..(.)(.)(.)..(.)......(.)/,$"),$=++;$.++;$.++;
$_++;$_++;($_,$\,$,)=($~.$"."$;$/$%[$?]$_$\$,$:$%[$?]",$"&$~,$#,);$,++
;$,++;$^|=$";`$_$\$,$/$:$;$~$*$%[$?]$.$~$*${#}$%[$?]$;$\$"$^$~$*.>&$=`
</syntaxhighlight>

A much shorter one, using only punctuation, based on the [https://metacpan.org/module/Acme::EyeDrops EyeDrops] module:
<syntaxhighlight lang="perl">
''=~('(?{'.('-)@.)@_*([]@!@/)(@)@-@),@(@@+@)'
^'][)@]`}`]()`@.@]@%[`}%[@`@!#@%[').',"})')
</syntaxhighlight>

[[ASCII art]] (to make this [[dromedary]]-shaped code work, the console size needs to be set to at least 119×48):<ref>Originally posted at [http://www.perlmonks.org/?node_id=528042 perlmonks.org] by user liverpole.</ref>
<syntaxhighlight lang="perl">
#
sub j(\$){($
P,$V)= @_;while($$P=~s:^
([()])::x){ $V+=('('eq$1)?-32:31
}$V+=ord( substr( $$P,0,1,""))-74} sub a{
my($I,$K,$ J,$L)=@_ ;$I=int($I*$M/$Z);$K=int(
$K*$M/$Z);$J=int($J*$M /$Z);$L=int($L*$M/$Z); $G=$
J-$I;$F=$L-$K;$E=(abs($ G)>=abs($F))?$G:$F;($E<0) and($
I,$K)=($J,$L);$E||=.01 ;for($i=0;$i<=abs$E;$i++ ){ $D->{$K
+int($i*$F/$E) }->{$I+int($i*$G/$E)}=1}}sub p{$D={};$
Z=$z||.01;map{ $H=$_;$I=$N=j$H;$K=$O=j$H;while($H){$q=ord
substr($H,0,1,"" );if(42==$q){$J=j$H;$L=j$H}else{$q-=43;$L =$q
%9;$J=($q-$L)/9;$L=$q-9*$J-4;$J-=4}$J+=$I;$L+=$K;a($I,$K,$J,$ L);
($I,$K)=($J,$L)}a($I,$K,$N,$O)}@_;my$T;map{$y=$_;map{ $T.=$D->{$y}
->{$_}?$\:' '}(-59..59);$T.="\n"}(-23..23);print"\e[H$T"}$w= eval{
require Win32::Console::ANSI};$b=$w?'1;7;':"";($j,$u,$s,$t,$a,$n,$o
,$h,$c,$k,$p,$e,$r,$l,$C)=split/}/,'Tw*JSK8IAg*PJ[*J@wR}*JR]*QJ[*J'.
'BA*JQK8I*JC}KUz]BAIJT]*QJ[R?-R[e]\RI'.'}Tn*JQ]wRAI*JDnR8QAU}wT8KT'.
']n*JEI*EJR*QJ]*JR*DJ@IQ[}*JSe*JD[n]*JPe*'.'JBI/KI}T8@?PcdnfgVCBRcP'.
'?ABKV]]}*JWe*JD[n]*JPe*JC?8B*JE};Vq*OJQ/IP['.'wQ}*JWeOe{n*EERk8;'.
'J*JC}/U*OJd[OI@*BJ*JXn*J>w]U}CWq*OJc8KJ?O[e]U/T*QJP?}*JSe*JCnTe'.
'QIAKJR}*JV]wRAI*J?}T]*RJcJI[\]3;U]Uq*PM[wV]W]WCT*DM*SJ'. 'ZP[Z'.
'PZa[\]UKVgogK9K*QJ[\]n[RI@*EH@IddR[Q[]T]T]T3o[dk*JE'. '[Z\U'.
'{T]*JPKTKK]*OJ[QIO[PIQIO[[gUKU\k*JE+J+J5R5AI*EJ00'. 'BCB*'.
'DMKKJIR[Q+*EJ0*EK';sub h{$\ = qw(% & @ x)[int rand
4];map{printf "\e[$b;%dm",int(rand 6)+101-60* ($w
||0);system( "cls")if$w ;($A,$S)= ($_[1], $
_[0]);($M, @,)= split '}';for( $z=256
;$z>0; $z -=$S){$S*= $A;p @,} sleep$_
[2];while ($_[3]&&($ z+=$ S) <=256){
p@,}}("". "32}7D$j" ."}AG". "$u}OG"
."$s}WG" ."$t","" ."24}(" ."IJ$a"
."}1G$n" ."}CO$o" ."}GG$t" ."}QC"
."$h}" ."^G$e" ."})IG" ."$r",
"32}?" ."H$p}FG$e}QG$r". "}ZC"
."$l", "28}(LC" ."" ."".
"$h}:" ."J$a}EG". "$c"
."}M" ."C$k}ZG". "$e"
."}" ."dG$r","18" ."}("
."D;" ."$C" )}{h(16 ,1,1,0
);h(8, .98,0,0 );h(16 ,1,1,1)
;h(8.0 ,0.98,0, 1); redo}###
#written 060204 by
#liverpole @@@@@@@
#@@@@@@@@@@@
</syntaxhighlight>

==See also==
*[["Hello, World!" program]]
*[[Obfuscated Perl Contest]]
*[[Perl#Perl pastimes|Perl golf]]

==References==
{{Reflist}}

== Further reading ==
* {{cite book|pages=[https://archive.org/details/advancedperlprog00coze/page/n276 261]&ndash;263|title=Advanced Perl Programming|url=https://archive.org/details/advancedperlprog00coze|url-access=limited|author=Simon Cozens|publisher=O'Reilly|year=2005|isbn=9780596004569}}

==External links==
* [https://web.archive.org/web/20041209175230/http://www-106.ibm.com/developerworks/linux/library/l-japh.html Cultured Perl: The Elegance of JAPH]
* [http://www.cpan.org/misc/japh Cpan.org], a collection of JAPHs at [[CPAN]].
* [https://stackoverflow.com/q/14440594 How does this famous JAPh work?] and [http://www.perlmonks.org/?node_id=290607 Fun With Reserved Keywords] at Stack Overflow explain how blokhead's code works.

{{Perl}}

[[Category:Perl]]
[[Category:English phrases]]
[[Category:Software obfuscation]]
[[Category:Test items in computer languages]]
[[Category:Computer programming folklore]]

Revision as of 21:36, 21 August 2023

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