// simple array parsing (insufficient for execution)

/ predicates

N:{~Z[x]|V[x]|A x}                                / are nouns
Z:{(f'x)_lin,"\000"}                              / are blanks
V:{x _lin"~!@#$%^&*-_=+|:<,>.?"}                  / are verbs
A:{(f'x)_lin"/\\'"}                               / are adverbs
Q:"\""=                                           / are quotes
C:{(4::'x)_lin 3 -3}                              / are characters

/ transformation rules

v:{s/[x;&V[x]&~|/-1!'(A;V;Z)@\:x]}                / vn <- nv
a:{s/[t;&-1!N[x]&1!A t:s/[x;&A[x]&-1!V x]]}       / av <- va, abv <- bva
s:{@[x;y-1 0;:;x y-0 1]}                          / yzx <- xyz

/ execution and nesting

f:(*:)/                                           / first atom
l:(*|:)/                                          / last atom
m:{j[x]C[x]&N x}                                  / multichar 
c:{h[x]A x}                                       / reverse enclose adverb trains
q:{g[x]Q[x]|(~=)\Q x}                             / enclose quotations 
k:{(-1!k)|k:</+\'x~\:/:y}                         / paired
p:{e'g[x]k[x]")("}                                / (..;a;..)
e:{:[Q[*x]|@x;x;,parse 1_-1_ x]}                  / parse if not string or atom
h:{@[g[x]y;&f'g[y]y;|:]}                          / reverse subsequences
i:{@[g[x]y;&*:'g[y]y;:;0]}                        / enclose valence
j:{@[g[x]y;&*:'g[y]y;$:]}                         / names
g:{{:[1=#x;*x;x]}'(&1,~&':y)_ x}                  / enclose subsequences
x:{1!(2#"\000"),x}                                / pad
y:{{:[4:y;x,,y;V l y;x,y;x,*y]}/[();1_-1_ x]}     / flatten
z:{{:[y;x,z;x,,z]}/[();A x;x]}                    / disclose adverb trains

/ parse tree

parse:z y v a c m p q x@                          / parse tree

/ examples 

parse"20+3"
parse"3+20"
parse"(~<)'x"
parse"+/'"
parse"(+/')x"
parse"100-12"
parse"10+!12"
parse"abc=def"
parse"+/'x"
parse"a+b-*c"
parse"a++/b-c"
parse"a+b+/c-d"
parse"a+b+/*'c-d"
parse"(a+b)-c*d"
parse"a+b=\"def\""
parse"2+3-"
parse"a+/b"

\

("+";"20";,"3")
("+";,"3";"20")
("'";"~<";,"x")
"'/+"
("'";"/";"+";,"x")
("-";"100";"12")
("+";"10";"!";"12")
("=";"abc";"def")
("'";"/";"+";,"x")
("+";,"a";"-";,"b";"*";,"c")
("+";,"a";"/";"+";"-";,"b";,"c")
("+";,"a";"/";"+";,"b";"-";,"c";,"d")
("+";,"a";"/";"+";,"b";"'";"*";"-";,"c";,"d")
("-";"+";,"a";,"b";"*";,"c";,"d")
("+";,"a";"=";,"b";"\"def\"")
("+";,"2";"-";,"3")
("/";"+";,"a";,"b")
  
'/+x
2100

a+/'x
'a/+x
30100