#include <stdio.h>  // printf(char *, ...)
#include <stdlib.h> // exit(int)

/*
 * For grammar: (https://en.wikipedia.org/wiki/Recursive_ascent_parser)
 * (R1)  expr : expr _ '+' term   { $$ = $1 + $3; }
 * (R2)       | expr _ '-' term   { $$ = $1 - $3; }
 * (R3)       | _ term            { $$ = $1; }
 *            ;
 *
 * (R4)  term : _ '(' expr ')'    { $$ = $2; }
 * (R5)       | _ num             { $$ = $1; }
 *            ;
 *
 * (R6)  num : _ '0'              { $$ = 0; }
 * (R7)      | _ '1'              { $$ = 1; }
 *           ;
 */

#pragma GCC diagnostic ignored "-Wunused-value"
#pragma GCC diagnostic ignored "-Wunused-parameter"

#define DIE(...) (printf("ERROR %s:%d\n", __FILE__, __LINE__), __VA_OPT__(exit(__VA_ARGS__),) exit(1), 1)

enum nonterminal { INVAILID, EXPR, TERM, NUM };
struct result { enum nonterminal nonterm; int value; int depth; char *s; };

struct args   { int args[2]; };
#define new_arg(...) (struct args){{__VA_ARGS__}}
#define get_arg(a, n) ((a).args[n])

// top-down
struct result rule0(char *s, struct args a);
struct result rule1(char *s, struct args a);
struct result rule2(char *s, struct args a);
struct result rule3(char *s, struct args a);
struct result rule4(char *s, struct args a);
struct result rule5(char *s, struct args a);
struct result rule6(char *s, struct args a);
struct result rule7(char *s, struct args a);

// bottom-up
struct result accept(char *s, struct args a);
struct result expr(char *s, struct args a);
struct result expr2(char *s, struct args a);
struct result term(char *s, struct args a);
struct result num(char *s, struct args a);

int main(void)
{
    char *s = "1-((0-1)+1+1+1+1+1)-0+1-(((1)))+1+1+1-1+0+(1-0+1)-1-0";
    struct result r = accept(s, new_arg(0));
    printf("%s = %d\n", s, r.value);
    return 0;
}

char *eat(char *s, char c)
{
    if(*s == c)
        return s + 1;
    else DIE();
}

struct result rule0(char *s, struct args a)
{
    struct result r = {0, 0, 0, s};
    r = expr(r.s, a);
    r.s = eat(r.s, '\0');
    return r;
}

struct result rule1(char *s, struct args a)
{
    struct result r = {0, 0, 0, s};
    r.s = eat(r.s, '+');
    r = term(r.s, a);
    return (struct result){EXPR, get_arg(a, 0) + r.value, 0, r.s};
}

struct result rule2(char *s, struct args a)
{
    struct result r = {0, 0, 0, s};
    r.s = eat(r.s, '-');
    r = term(r.s, a);
    return (struct result){EXPR, get_arg(a, 0) - r.value, 0, r.s};
}

struct result rule3(char *s, struct args a)
{
    struct result r = {0, 0, 0, s};
    r = term(r.s, a);
    return (struct result){EXPR, r.value, 0, r.s};
}

struct result rule4(char *s, struct args a)
{
    struct result r = {0, 0, 0, s};
    r.s = eat(r.s, '(');
    r = expr(r.s, a);
    r.s = eat(r.s, ')');
    return (struct result){EXPR, r.value, 1, r.s};
}

struct result rule5(char *s, struct args a)
{
    struct result r = {0, 0, 0, s};
    r = num(r.s, a);
    return (struct result){TERM, r.value, 0, r.s};
}

struct result rule6(char *s, struct args a)
{
    struct result r = {0, 0, 0, s};
    r.s = eat(r.s, '0');
    return (struct result){NUM, 0, 0, r.s};
}

struct result rule7(char *s, struct args a)
{
    struct result r = {0, 0, 0, s};
    r.s = eat(r.s, '1');
    return (struct result){NUM, 1, 0, r.s};
}

struct result accept(char *s, struct args a)
{
    struct result r = {0};
    switch(*s) {
    case '(':
    case '0':
    case '1': r = rule0(s, a); break;
    default: DIE();
    }

    return r;
}

struct result expr(char *s, struct args a)
{
    struct result r = {0};
    switch(*s) {
    case '(':
    case '0':
    case '1': r = rule3(s, a); break;
    default: DIE();
    }

    struct result r2 = r;
    while(r2.depth == 0) {
        r = r2;
        switch(r.nonterm) {
        case EXPR: r2 = expr2(r.s, new_arg(r.value)); break;
        default: DIE();
        }
    }

    r.depth--;
    return r;   
}

struct result expr2(char *s, struct args a)
{
    struct result r = {0};
    switch(*s) {
    case '+': r = rule1(s, a); break;
    case '-': r = rule2(s, a); break;
    default: r.depth = 1;
    }

    return r;
}
    
struct result term(char *s, struct args a)
{
    struct result r = {0};
    switch(*s) {
    case '(': r = rule4(s, a); break;
    case '0': r = rule5(s, a); break;
    case '1': r = rule5(s, a); break;
    default: DIE();
    }

    return r;
}

struct result num(char *s, struct args a)
{
    struct result r = {0};
    switch(*s) {
    case '0': r = rule6(s, a); break;
    case '1': r = rule7(s, a); break;
    default: DIE();
    }

    return r;
}