ncn.c

#include <stdlib.h>  // malloc,labs
#include <stdio.h>   // printf
#include <string.h>  // strlen
typedef char C;
typedef long I;
typedef void V;
typedef struct a{I t,r,d[3],p[2];}*A;
#define O printf
#define R return
#define DO(n,x) {I i=0,_n=(n);for(;i<_n;++i){x;}}

I *ma(I n){R(I*)malloc(n*4);}
V mv(I*d,I*s,I n){DO(n,d[i]=s[i]);}
I tr(I r,I*d){I z=1;DO(r,z=z*d[i]);R z;}
A ga(I t,I r,I*d){A z=(A)ma(5+tr(r,d));z->t=t,z->r=r,mv(z->d,d,r);R z;}
A iota(A w){I n=*w->p;A z=ga(0,1,&n);DO(n,z->p[i]=i);R z;}
A plus(A a, A w){I r=w->r,*d=w->d,n=tr(r,d);A z=ga(0,r,d);
  DO(n,z->p[i]=a->p[i]+w->p[i]);R z;}
A from(A a, A w){I r=w->r-1,*d=w->d+1,n=tr(r,d);
  A z=ga(w->t,r,d);mv(z->p,w->p+(n**a->p),n);R z;}
A box(A w){A z=ga(1,0,0);*z->p=(I)w;R z;}
A cat(A a,A w){I an=tr(a->r,a->d),wn=tr(w->r,w->d),n=an+wn;
  A z=ga(w->t,1,&n);mv(z->p,a->p,an);mv(z->p+an,w->p,wn);R z;}
A find(A a,A w){}
A rsh(A a,A w){I r=a->r?*a->d:1,n=tr(r,a->p),wn=tr(w->r,w->d);
  A z=ga(w->t,r,a->p);mv(z->p,w->p,wn=n>wn?wn:n);
  if(n-=wn)mv(z->p+wn,z->p,n);R z;}
A sha(A w){A z=ga(0,1,&w->r);mv(z->p,w->d,w->r);R z;}
A id(A w){R w;}
A size(A w){A z=ga(0,0,0);*z->p=w->r?*w->d:1;R z;}
V pi(I i){O("%ld ",i);}
V nl(){O("\n");}
V pr(A w){I r=w->r,*d=w->d,n=tr(r,d);
  DO(r,pi(d[i])); nl();
  if(w->t)DO(n,O("< ");pr((A)(w->p[i])))
  else DO(n,pi(w->p[i])); nl();}

A (*vd[])()={0,plus,from,find,0,rsh,cat},
  (*vm[])()={0,id,size,iota,box,sha,0}; 
I qp(I a){R  a>='a'&&a<='z';}
I qv(I a){R labs(a)<'a';}
C vt[]="+{~<#,"; I st[26];
A ex(I *e){I a=*e;
  if(qp(a)){if(e[1]=='=')R(V*)(st[a-'a']=(I)ex(e+2));a= st[ a-'a'];}
  R qv(a)?(*vm[a])(ex(e+1)):e[1]?(*vd[e[1]])(a,ex(e+2)):(A)a;}
I noun(C c){A z;if(c<'0'||c>'9')R 0;z=ga(0,0,0);*z->p=c-'0';R(I)z;}
I verb(C c){I i=0;for(;vt[i];)if(vt[i++]==c)R i;R 0;}
I *wd(C *s){I a,n=strlen(s),*e=ma(n+1); C c; 
  DO(n,e[i]=(a=noun(c=s[i]))?a:(a=verb(c))?a:c); e[n]=0; R e;}

int main(){C s[99];while(gets(s))pr(ex(wd(s)));R 0;}