J.c

#include <stdlib.h>
#include <string.h>
#include <stdio.h>

typedef struct a {
    long t, r, d[3], p[2];
} *A;


long *ma(int n) {
    return (long *) malloc(n * 4);
}

void mv(long *d, long *s, int n) {
    for (long i = 0; i < n; ++i) {
        d[i] = s[i];
    }
}

int tr(int r, long *d) {
    long z = 1;
    {
        long i = 0, _n = (r);
        for (;
                i < _n;
                ++i) {
            z = z * d[i];
        }
    };
    return
            z;
}

A ga(int t, int r, long *d) {
    A z = (A) ma(5 + tr(r, d));
    z->t = t, z->r = r, mv(z->d, d, r);
    return z;
}

A iota(A w) {
    long n = *w->p;
    A z = ga(0, 1, &n);
    {
        long i = 0, _n = (n);
        for (; i < _n; ++i) { z->p[i] = i; }
    };
    return z;
}

A plus(A a, A w) {
    long r = w->r, *d = w->d, n = tr(r, d);
    A z = ga(0, r, d);
    {
        long i = 0, _n = (n);
        for (; i < _n; ++i) { z->p[i] = a->p[i] + w->p[i]; }
    };
    return z;
}

A from(A a, A w) {
    long 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);
    return z;
}

A box(A w) {
    A z = ga(1, 0, 0);
    *z->p = (long) w;
    return z;
}

A cat(A a, A w) {
    long 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);
    return z;
}

void find(A a, A w) { }

A rsh(A a, A w) {
    long 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);
    return z;
}

A sha(A w) {
    A z = ga(0, 1, &w->r);
    mv(z->p, w->d, w->r);
    return z;
}

A id(A w) { return w; }

A size(A w) {
    A z = ga(0, 0, 0);
    *z->p = w->r ? *w->d : 1;
    return z;
}

void pi(int i) { printf("%d ", i); }

void nl() { printf("\n"); }

void pr(A w) {
    long r = w->r, *d = w->d, n = tr(r, d);

    for (long i = 0; i < r; ++i) {
        pi(d[i]);
    }

    nl();

    if (w->t) {
        for (long i = 0; i < n; ++i) {
            printf("< ");
            pr(w->p[i]);
        }
    } else {
        for (long i = 0; i < n; ++i) {
            pi(w->p[i]);
        }
    };
    nl();
}

char vt[] = "+{~<#,";

A(*vd[])() = {0, plus, from, find, 0, rsh, cat},
(*vm[])() = {0, id, size, iota, box, sha, 0};

long st[26];

// boolean
int qp(a) { return a >= 'a' && a <= 'z'; }

// boolean
int qv(a) { return a < 'a'; }

A ex(long *e) {
    long a = *e;
    if (qp(a)) {
        if (e[1] == '=')return st[a - 'a'] = ex(e + 2);
        a = st[a - 'a'];
    }
    return qv(a) ? (*vm[a])(ex(e + 1)) : e[1] ? (*vd[e[1]])(a, ex(e + 2)) : (A) a;
}

// c is used like a char
A noun(int c) {
    A z;
    if (c < '0' || c > '9')return 0;
    z = ga(0, 0, 0);
    *z->p = c - '0';
    return z;
}

int verb(int c) {
    long i = 0;
    for (; vt[i];)if (vt[i++] == c)return i;
    return 0;
}

long *wd(char *s) {
    long a, n = strlen(s), *e = ma(n + 1);
    char c;
    {
        long i = 0, _n = (n);
        for (; i < _n; ++i) { e[i] = (a = noun(c = s[i])) ? a : (a = verb(c)) ? a : c; }
    };
    e[n] = 0;
    return e;
}

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