j stack language          parse                      list operators                      
                            (comment)                  #     length/non-list: -1         
32-bit type system          abc   symbol (max 6)       ,     cat                         
  ..000 list[quotation]     123   int (max 31 bit)    []i@   index                       
  ....1 int  x>>1           [..]  list/quote          [a]i v$store       [a]"#v$ (append)
  ...10 symbol x>>2                                                                      
  ..100 operator x>>3     numeric operators (dyadic) assign/quote/exec                   
heap memory                  +-*/% arith               [p][a]: assign [p] to symbol a    
  0     total memory(log)    <=>   compare             a       lookup symbol a and exec  
  1     stack                                          [p].    exec                      
  2     stack(swap)                                                                      
  3     key/val list      stack operators            control                             
  4..32 free list           ~"_|  swap dup pop roll    c[t][e]?      (if c then t else e)
  33... data(buckets)          !  print stack          }  pop/push to swap stack         
unused '\^`;              canvas draw [arg][func]&     {  pop/push from swap stack

j.w source of the wasm module

(show/hide)

stk:V:I{}draw:V:II{}

j:I:I{(~I 0)? :ii x;(1~lu 110)?((41~x)?110 as 0;rz);(40~x)?(110 as 1;rz);                       /p
 n:lu 114;(47<x)?(58>x)?(x-:48;(~x|n)?(pc 1;rz);n*:10;n+:x;114 as n;rz);n?(pc 1|n<<1;114 as 0); /a
 y:lu 118;(96<x)?(123>x)?(y*:32;y+:x-96;118 as y;rz);y?(pc 2|y<<2;118 as 0);                    /r
 $[33>x;(10~x)?(exe x;pu mk 0; :1);91~x;pu mk 0;93~x;pc lp;pc 4|(x-33)<<3];0}                   /sexe

ii.I:I{0::x;p:128;i:7;(i<x)?/((4*i)::p;p*:2;i+:1);4::mk sz;8::mk sz;(4+I 4)::0;(4+I 8)::0;pu mk 0;12::mk 0;110 as 0;114 as 0;118 as 0;x}
bk.I:I{r:32-*7+4*x;(r<4)? :4;r}rx.I:I{xl?(x::1+I x);x}nn.I:I{I 4+x}nx:{(nn x)}xl:{(~x&7)}rz:{ :0}sz:{126}
dx.V:I{x?xl?(r:(I x)-1;x::r;(~r)?(n:I x+4;p:x+8;n/(dx I p;p+:4);fr x))}fr.V:I{p:4*bk I 4+x;x::I p;p::x}
mk.I:I{t:bk x;i:4*t;m:4*I 0;(~I i)?/((i>='m)?!;i+:4);a:I i;i::I a;k:i-4;(k>=4*t)?/(u:a+1<<k>>2;u::I k;k::u;k-:4);a::1;(a+4)::x;a}
sw.I:I{s:I 4;4::I 8;8::s;x}pp.I:I{t:po;x:sw x;pu t;x}

lc.I:II{n:nx;(1~I x)?((bk 1+n)~bk n)?((8+x+4*n)::y;(4+x)::1+n; :x);r:mk 1+n;(cp(x;r;n))::y;dx x;r}
cp.I:III{x+:8;y+:8;z/(y::rx I x;x+:4;y+:4);y}pc.V:I{pu lp lc x}
pl.I:I{4+x+4*nx}fi.I:I{(~nx)?!;r:rx I x+8;dx x;r}us.I:I{(1~I x)? :x;n:nx;r:mk n;n:cp(x;r;n);dx x;r}
ip:{(ipop x)}ipop.I:I{x:po;(~x&1)?!;r:x>>1;(0>'x)?r|:2147483648;r}lp:{(lpop x)}lpop.I:I{x:po;(7&x)?!;x}
pi.V:I{pu 1+2*x}ln.I:I{p:fn x;(~p)?!;rx I p}pu.V:I{s:I 4;n:nn s;(n~sz)?!;(4+s)::1+n;(pl s)::x}px:{pu x}
fn.I:I{s:I 12;n:(nn s)>>1;p:s+8;n/((x~I p)? :4+p;p+:8);0}lu.I:I{p:fn x;(~p)?!;I p}
ps.I:I{s:I 12;p:fn x;(~p)?(s:s lc x;s:s lc 1;p:pl s);12::s;p}as.V:II{(ps x)::y}
po:{(pop x)}pop.I:I{x:I 4;n:nx;(~n)?!;r:I x+4*1+n;(4+x)::n-1;r}

exe.V:I{x:lp;p:x+8;l:x;nx?l:pl x;(p<=l)?/(c:I p;$[2~c&3;(pu rx lu c;exe x);~4~c&7;pu rx c;740~c;x:sw pp x;724~c;x:pp sw x;(V.c>>3)(x)];p+:4);dx x}
add.V:I{pi ip+ip}sub.V:I{pi(-ip)+ip}mul.V:I{pi ip*ip}div.V:I{swp x;pi ip%ip}
mod.V:I{swp x;pi I?ip\'ip}lti.V:I{pi ip>'ip}eql.V:I{pi ip~ip}gti.V:I{pi ip<'ip}
dup.V:I{x:po;pu rx x;px}drp.V:I{dx po}swp.V:I{x:po;y:po;px;pu y}rol.V:I{x:po;y:po;z:po;px;pu z;pu y}
cnt.V:I{x:po;r:-1;xl?r:1+2*nx;dx x;pu r}atx.V:I{i:ip;l:lp;((i<0)+i>='nn l)?!;pu rx I 8+l+4*i;dx l}
amd.V:I{v:po;i:ip;a:us lp;n:nn a;$[i~n;a:a lc v;(i<'0)+i>'n;!;(ap:8+a+4*i;x:rx I ap;ap::v)];pu a}
cat.V:I{y:po;x:po;(7&x)?x:(mk 0)lc x;$[7&y;x:x lc y;(yp:y+8;(nn y)/(x:x lc rx I yp;yp+:4);dx y)];px}
asn.V:I{y:fi lp;(~2~y&3)?!;v:po;(v&7)?(v:(mk 0)lc v);p:ps y;dx I p;p::v}
ife.V:I{e:po;t:po;$[~ip;(dx t;pu e);(dx e;pu t)];exe x}drw.V:I{y:lp;x:lp;x draw y;dx x;dx y}
0:{stk;dup;cnt;amd;mod;drw;xxx;xxx;xxx;mul;add;cat;sub;exe;div}25:{asn;xxx;lti;eql;gti;ife;atx}62:{drp}91:{rol;xxx;swp}

w < j.w > j.wasm(2576 byte)

arithmetics

basic arithmetics is defined on integers
1 2+ (3) 1 2- (-1) 2 3* (6) 6 2/ (3) 6 4/ (1) (integer division) 6 4% (2) (modulo) 01- (-1) (negative numbers)
comparison
3 3= (1) 1 2< (1) 1 2> (0) 01-0< (1)

stack-operators

1 2~ (2 1) (swap/exchange) 1" (1 1) (duplicate) 1 2_ (1) (pop/drop) 1 2 3| (3 1 2) (roll) [1+]"__ ()

catenate

catenate, append, cons, enlist
1 2, ([1 2]) (make a list from two atoms) 1[2], ([1 2]) (x gets enlisted if atom) [1 2]3, ([1 2 3]) (append atom y to list x) [1][2 3], ([1 2 3]) (two lists are merged) [][1 2], ([1 2]) (this does not enlist)
set list index
[1 2 3]0 5$ ([5 2 3]) (set list at index 0 to 5) [1 2 3]3 5$ ([1 2 3 5]) (amend to # appends) [1 3 2]# (3) (count/length)
enlist and cat
[[]~0~$][enlist]: () [1 2]enlist ([[1 2]]) [enlist,][cat]: () [1 2][3 4]cat ([1 2 [3 4]]) (cat appends y as a single element)

branch

1[2 3+][4 5+]? (5) (? expects an integer as a boolean) 0[2 3+][4 5+]? (9) [}}.{{?][ifte]: () (ifte is similar but expects a quotation) 1 1[=][2][3]ifte (2) 1 5[=][2][3]ifte (3)
if
[[]?][if]: () (if has no then clause) 2 1[2+]if (4) 2 0[3*]if (2) [}.{[]?][iff]: () (iff expects a quotation) 2 1 1[<][2+]iff (2) 2 1 2[<][3*]iff (6)

loop

while
[}"}.{{"|}cat{cat[while],[]?][while]: () ([C][D]while "while C do D) 5["][1-]while (0) [}"1-}{{"|}cat{cat[times],[]?][times]: () (n[P]times do P n times) 1 4[2*]times (16)

recursion

tail recursion: exec P. if true, exec T, else exec R recurse
[}}"}.{{"|{"}|}cat{cat{cat[tailrc],?][tailrc]: () ([P][T][R]tailrc) 1["5=][10*][1+]tailrc (50)

array

[[]~["][1-"},{]while_][ntil]: () (til n downwards) 5 ntil ([4 3 2 1 0]) [}[]["#]{,[<],["#,]while][til]: () (n til) 5 til ([0 1 2 3 4]) [0@][first]: () [1 2 3]first (1) ["#1-@][last]: () [1 2 3]last (3)

each

each/map: apply f to each element of A
["}#~"}#<{{||][balt]: () (a b -- a b ba<) [balt["|#~"|~@|}|~"}.~"#||${~{~eachs][|__]?][eachs]: () [~[]eachs][each]: () ([A][f]each) [1 2 3][0~-]each ([-1 -2 -3])
dyadic each
[balt["}#~"}~"|@|~"}~@|~"}.{~{~{~{"#||$eachds][}___{]?][eachds]: () [|[]eachds][eachd]: () ([A][B][f]eachd) [3 2 1][4 5 6][-]eachd ([-1 -3 -5])
each right
[balt["}#~"}~@~"}~||"}.{~{~{~{~,eachrs][}___{]?][eachrs]: () [|[]eachrs][eachr]: () (A[B][f]eachr) 1[1 2 3][+]eachr ([2 3 4])
each left
[[~]~,|~[]eachrs][eachl]: () [1 2 3]1[-]eachl ([0 1 2])
at/index
[[@]eachr][at]: () [2 7 8 9][0 2]at ([2 8])
take/drop/reverse
[til at][take]: () [3 5 0 2]3take ([3 5 0]) ["#ntil at][rev]: () [~"#ntil~|"#||-take rev at][drop]: () [3 2 1 0 5]2drop ([1 0 5])
amend multiple
[~"#["1 drop}first ~"}${{~amend][__]?][amend]: () [1 2 3 4][0 3][7 8 9]amend ([[7 8 9] 2 3 [7 8 9]])
over/fold, over initial
["#}~"}~{{<["}~"1+}@~"}.{{{overs][___]?][overs]: () [~0~overs][overi]: () 1[1 2 3][+]overi (7) [}"first~1drop{overi][over]: () [1 2 3][+]over (6)
where
[[]~0~ [~"}~[,][_]?{1+]overi_][where]: () [0 1 1 0 1]where ([1 2 4])

extend

atomic extension, vectorize
[}"#0<2*}~"#0<}~{{+[[eachd][eachr][eachl][.]]~@{~.][atomx]: () ([f]atomx) [[+]atomx][add]: () [[-]atomx][sub]: () [[*]atomx][mul]: () [[/]atomx][div]: () [[<]atomx][lt]: () [[>]atomx][gt]: () [[=]atomx][eq]: () [[=0=]atomx][neq]: () [0eq][not]: () 1[2 3 4]add ([3 4 5])

canvas api

[[97 114 99]&][arc]: () (arc: [x y r sa ea]arc) [[97 114 99 84 111]&][arcto]: () (arcTo: [xa ya xb yb r]arcto) [[][98 101 103 105 110 80 97 116 104]&][bpath]: () (beginPath: bpath) [[98 101 122 105 101 114 67 117 114 118 101 84 111]&][bezito]: () (bezierCurveTo: [cxa cya cxb cyb x y]bezito) [[99 108 101 97 114 82 101 99 116]&][crect]: () (clearRect: [x y w h]crect) [[][99 108 105 112]&][clip]: () (clip: clip) [[][99 108 111 115 101 80 97 116 104]&][cpath]: () (closePath: cpath) [[99 114 101 97 116 101 76 105 110 101 97 114 71 114 97 100 105 101 110 116]&][lingrd]:() (createLinearGradient: [xa ya xb yb]lingrd) [[99 114 101 97 116 101 82 97 100 105 97 108 71 114 97 100 105 101 110 116]&][radgrd]: () (createRadialGradient: [xa ya ra xb yb rb]radgrd) [[101 108 108 105 112 115 101]&][ellips]: () (ellipse: [x y rx ry rot sa ea]ellips) [[][102 105 108 108]&][fill]: () (fill: fill) [[102 105 108 108 82 101 99 116]&][frect]: () (fillRect: [x y w h]frect) [[102 105 108 108 83 116 121 108 101]&][fstyle]: () (fillStyle: [color|gradient]fstyle) [[102 105 108 108 84 101 120 116]&][ftext]: () (fillText: [s x y]ftext) [[102 111 110 116]&][font]: () (font: [name]font) [[108 105 110 101 67 97 112]&][lcap]: () (lineCap: [butt|round|square]lcap) [[108 105 110 101 68 97 115 104 79 102 102 115 101 116]&][ldoff]: () (lineDashOffset: [i]ldoff) [[108 105 110 101 74 111 105 110]&][ljoin]: () (lineJoin: [bevel|round|miter]ljoin) [[108 105 110 101 84 111]&][lineto]: () (lineTo: [x y]lineto) [[108 105 110 101 87 105 100 116 104]&][lwidth]: () (lineWidth: [i]lwidth) [[109 111 118 101 84 111]&][moveto]: () (moveTo: [x y]moveto) [[113 117 97 100 114 97 116 105 99 67 117 114 118 101 84 111]&][qcto]: () (quadraticCurveTo: [cx cy x y]qcto) [[114 101 99 116]&][rect]: () (rect: [x y w h]rect) [[][114 101 115 101 116 84 114 97 110 115 102 111 114 109]&][rstra]: () (resetTransform: rstra) [[][114 101 115 116 111 114 101]&][rstore]: () (restore: rstore) [[114 111 116 97 116 101]&][rotate]: () (rotate: [a]rotate) [[][115 97 118 101]&][save]: () (save: save) [[115 99 97 108 101]&][scale]: () (scale: [x y]scale) [[115 101 116 76 105 110 101 68 97 115 104]&][sldash]: () (setLineDash: [segments]sldash) [[115 101 116 84 114 97 110 115 102 111 114 109]&][setra]: () (setTransform: [a b c d e f]setra) [[115 104 97 100 111 119 66 108 117 114]&][shblur]: () (shadowBlur: [i]shblur) [[115 104 97 100 111 119 67 111 108 111 114]&][shcol]: () (shadowColor: [c]shcol) [[115 104 97 100 111 119 79 102 102 115 101 116 88]&][shoffx]: () (shadowOffsetX: [i]shoffx) [[115 104 97 100 111 119 79 102 102 115 101 116 89]&][shoffy]: () (shadowOffsetY: [i]shoffy) [[][115 116 114 111 107 101]&][stroke]: () (stroke: stroke) [[115 116 114 111 107 101 82 101 99 116]&][srect]: () (strokeRect: [x y w h]srect) [[115 116 114 111 107 101 83 116 121 108 101]&][sstyle]: () (strokeStyle: [color|gradient]sstyle) [[115 116 114 111 107 101 84 101 120 116]&][stext]: () (strokeText: [s x y]stext) [[116 101 120 116 65 108 105 103 110]&][talign]: () (textAlign: [left|right|center|start|end]talign) [[116 101 120 116 66 97 115 101 108 105 110 101]&][tbline]: () (textBaseline: [b]tbline) [[116 114 97 110 115 102 111 114 109]&][transf]: () (transform: [a b c d e f]transf) [[116 114 97 110 115 108 97 116 101]&][transl]: () (translate: [x y]transl)

definitions

symbol	quotation
enlist	[]~0~$
cat	enlist,
ifte	}}.{{?
if	[]?
iff	}.{[]?
while	}"}.{{"\|}cat{cat[while],[]?
times	}"1-}{{"\|}cat{cat[times],[]?
tailrc	}}"}.{{"\|{"}\|}cat{cat{cat[tailrc],?
ntil	[]~["][1-"},{]while_
til	}[]["#]{,[<],["#,]while
first	0@
last	"#1-@
balt	"}#~"}#<{{\|\|
eachs	balt["\|#~"\|~@\|}\|~"}.~"#\|\|${~{~eachs][\|__]?
each	~[]eachs
eachds	balt["}#~"}~"\|@\|~"}~@\|~"}.{~{~{~{"#\|\|$eachds][}___{]?
eachd	\|[]eachds
eachrs	balt["}#~"}~@~"}~\|\|"}.{~{~{~{~,eachrs][}___{]?
eachr	\|[]eachrs
eachl	[~]~,\|~[]eachrs
at	[@]eachr
take	til at
rev	"#ntil at
drop	~"#ntil~\|"#\|\|-take rev at
amend	~"#["1 drop}first ~"}${{~amend][__]?
overs	"#}~"}~{{<["}~"1+}@~"}.{{{overs][___]?
overi	~0~overs
over	}"first~1drop{overi
where	[]~0~ [~"}~[,][_]?{1+]overi_
atomx	}"#0<2*}~"#0<}~{{+[[eachd][eachr][eachl][.]]~@{~.
add	[+]atomx
sub	[-]atomx
mul	[*]atomx
div	[/]atomx
lt	[<]atomx
gt	[>]atomx
eq	[=]atomx
neq	[=0=]atomx
not	0eq
arc	[97 114 99]&
arcto	[97 114 99 84 111]&
bpath	[][98 101 103 105 110 80 97 116 104]&
bezito	[98 101 122 105 101 114 67 117 114 118 101 84 111]&
crect	[99 108 101 97 114 82 101 99 116]&
clip	[][99 108 105 112]&
cpath	[][99 108 111 115 101 80 97 116 104]&
lingrd	[99 114 101 97 116 101 76 105 110 101 97 114 71 114 97 100 105 101 110 116]&
radgrd	[99 114 101 97 116 101 82 97 100 105 97 108 71 114 97 100 105 101 110 116]&
ellips	[101 108 108 105 112 115 101]&
fill	[][102 105 108 108]&
frect	[102 105 108 108 82 101 99 116]&
fstyle	[102 105 108 108 83 116 121 108 101]&
ftext	[102 105 108 108 84 101 120 116]&
font	[102 111 110 116]&
lcap	[108 105 110 101 67 97 112]&
ldoff	[108 105 110 101 68 97 115 104 79 102 102 115 101 116]&
ljoin	[108 105 110 101 74 111 105 110]&
lineto	[108 105 110 101 84 111]&
lwidth	[108 105 110 101 87 105 100 116 104]&
moveto	[109 111 118 101 84 111]&
qcto	[113 117 97 100 114 97 116 105 99 67 117 114 118 101 84 111]&
rect	[114 101 99 116]&
rstra	[][114 101 115 101 116 84 114 97 110 115 102 111 114 109]&
rstore	[][114 101 115 116 111 114 101]&
rotate	[114 111 116 97 116 101]&
save	[][115 97 118 101]&
scale	[115 99 97 108 101]&
sldash	[115 101 116 76 105 110 101 68 97 115 104]&
setra	[115 101 116 84 114 97 110 115 102 111 114 109]&
shblur	[115 104 97 100 111 119 66 108 117 114]&
shcol	[115 104 97 100 111 119 67 111 108 111 114]&
shoffx	[115 104 97 100 111 119 79 102 102 115 101 116 88]&
shoffy	[115 104 97 100 111 119 79 102 102 115 101 116 89]&
stroke	[][115 116 114 111 107 101]&
srect	[115 116 114 111 107 101 82 101 99 116]&
sstyle	[115 116 114 111 107 101 83 116 121 108 101]&
stext	[115 116 114 111 107 101 84 101 120 116]&
talign	[116 101 120 116 65 108 105 103 110]&
tbline	[116 101 120 116 66 97 115 101 108 105 110 101]&
transf	[116 114 97 110 115 102 111 114 109]&
transl	[116 114 97 110 115 108 97 116 101]&

examples

ellipse roll koch sierpinski arrowhead tree square-spiral reuleux plant

ref
src
arithmetics
stack-operators
catenate
branch
loop
recursion
array
each
extend
canvas api
definitions
examples