string/parser.hpp

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• Last update: 2022-10-20 00:25:59+09:00
• Include: #include "string/parser.hpp"

Depends on

• template.hpp

Code

#pragma once

#include "../template.hpp"

using state = string::const_iterator;
struct parse_error {};

void consume(state &cur, char expected) {
    if (*cur == expected) {
        ++cur;
    } else {
        cerr << "Expected '" << expected << "' but got '" << *cur << "'" << endl;
        cerr << "Rest string is '";
        while (*cur) cerr << *cur++;
        cerr << "'" << endl;
        throw parse_error();
    }
}

struct parser {
    ll expr(state &cur) {
        ll ret = term(cur);
        while (true) {
            if (*cur == '+') {
                consume(cur, '+');
                ret += term(cur);
            } else if (*cur == '-') {
                consume(cur, '-');
                ret -= term(cur);
            } else {
                break;
            }
        }
        return ret;
    }
    ll term(state &cur) {
        ll ret = factor(cur);
        while (true) {
            if (*cur == '*') {
                consume(cur, '*');
                ret *= factor(cur);
            } else if (*cur == '/') {
                consume(cur, '/');
                ret /= factor(cur);
            } else {
                break;
            }
        }
        return ret;
    }
    ll factor(state &cur) {
        if (*cur == '(') {
            consume(cur, '(');
            ll ret = expr(cur);
            consume(cur, ')');
            return ret;
        } else {
            return number(cur);
        }
    }
    ll number(state &cur) {
        ll ret = 0;
        while (isdigit(*cur)) {
            ret *= 10;
            ret += *cur - '0';
            ++cur;
        }
        return ret;
    }
};

#line 2 "string/parser.hpp"

#line 2 "template.hpp"

#include <bits/stdc++.h>
using namespace std;

#define all(a) begin(a), end(a)
#define rall(a) rbegin(a), rend(a)
#define uniq(a) (a).erase(unique(all(a)), (a).end())
#define t0 first
#define t1 second
using ll = long long;
using ull = unsigned long long;
using pll = pair<ll, ll>;
using vll = vector<ll>;
constexpr double pi = 3.14159265358979323846;
constexpr ll dy[9] = {0, 1, 0, -1, 1, 1, -1, -1, 0};
constexpr ll dx[9] = {1, 0, -1, 0, 1, -1, -1, 1, 0};
constexpr ll sign(ll a) { return (a > 0) - (a < 0); }
constexpr ll fdiv(ll a, ll b) { return a / b - ((a ^ b) < 0 && a % b); }
constexpr ll cdiv(ll a, ll b) { return -fdiv(-a, b); }
constexpr ll pw(ll n) { return 1ll << n; }
constexpr ll flg(ll n) { return 63 - __builtin_clzll(n); }
constexpr ll clg(ll n) { return n == 1 ? 0 : flg(n - 1) + 1; }
constexpr ll safemod(ll x, ll mod) { return (x % mod + mod) % mod; }
template <typename T> using priority_queue_rev = priority_queue<T, vector<T>, greater<T>>;
template <typename T> constexpr T sq(const T &a) { return a * a; }
template <typename T, typename U> constexpr bool chmax(T &a, const U &b) { return a < b ? a = b, true : false; }
template <typename T, typename U> constexpr bool chmin(T &a, const U &b) { return a > b ? a = b, true : false; }
template <typename T, typename U> ostream &operator<<(ostream &os, const pair<T, U> &a) {
    os << "(" << a.first << ", " << a.second << ")";
    return os;
}
template <typename T, typename U, typename V> ostream &operator<<(ostream &os, const tuple<T, U, V> &a) {
    os << "(" << get<0>(a) << ", " << get<1>(a) << ", " << get<2>(a) << ")";
    return os;
}
template <typename T> ostream &operator<<(ostream &os, const vector<T> &a) {
    os << "(";
    for (auto itr = a.begin(); itr != a.end(); ++itr) os << *itr << (next(itr) != a.end() ? ", " : "");
    os << ")";
    return os;
}
template <typename T> ostream &operator<<(ostream &os, const set<T> &a) {
    os << "(";
    for (auto itr = a.begin(); itr != a.end(); ++itr) os << *itr << (next(itr) != a.end() ? ", " : "");
    os << ")";
    return os;
}
template <typename T> ostream &operator<<(ostream &os, const multiset<T> &a) {
    os << "(";
    for (auto itr = a.begin(); itr != a.end(); ++itr) os << *itr << (next(itr) != a.end() ? ", " : "");
    os << ")";
    return os;
}
template <typename T, typename U> ostream &operator<<(ostream &os, const map<T, U> &a) {
    os << "(";
    for (auto itr = a.begin(); itr != a.end(); ++itr) os << *itr << (next(itr) != a.end() ? ", " : "");
    os << ")";
    return os;
}
#ifdef ONLINE_JUDGE
#define dump(...) (void(0))
#else
void debug() { cerr << endl; }
template <typename Head, typename... Tail> void debug(Head &&head, Tail &&... tail) {
    cerr << head;
    if (sizeof...(Tail)) cerr << ", ";
    debug(tail...);
}
#define dump(...) cerr << __LINE__ << ": " << #__VA_ARGS__ << " = ", debug(__VA_ARGS__)
#endif
struct rep {
    struct itr {
        ll v;
        itr(ll v) : v(v) {}
        void operator++() { ++v; }
        ll operator*() const { return v; }
        bool operator!=(itr i) const { return v < *i; }
    };
    ll l, r;
    rep(ll l, ll r) : l(l), r(r) {}
    rep(ll r) : rep(0, r) {}
    itr begin() const { return l; };
    itr end() const { return r; };
};
struct per {
    struct itr {
        ll v;
        itr(ll v) : v(v) {}
        void operator++() { --v; }
        ll operator*() const { return v; }
        bool operator!=(itr i) const { return v > *i; }
    };
    ll l, r;
    per(ll l, ll r) : l(l), r(r) {}
    per(ll r) : per(0, r) {}
    itr begin() const { return r - 1; };
    itr end() const { return l - 1; };
};
struct io_setup {
    static constexpr int PREC = 20;
    io_setup() {
        cout << fixed << setprecision(PREC);
        cerr << fixed << setprecision(PREC);
    };
} iOS;
#line 4 "string/parser.hpp"

using state = string::const_iterator;
struct parse_error {};

void consume(state &cur, char expected) {
    if (*cur == expected) {
        ++cur;
    } else {
        cerr << "Expected '" << expected << "' but got '" << *cur << "'" << endl;
        cerr << "Rest string is '";
        while (*cur) cerr << *cur++;
        cerr << "'" << endl;
        throw parse_error();
    }
}

struct parser {
    ll expr(state &cur) {
        ll ret = term(cur);
        while (true) {
            if (*cur == '+') {
                consume(cur, '+');
                ret += term(cur);
            } else if (*cur == '-') {
                consume(cur, '-');
                ret -= term(cur);
            } else {
                break;
            }
        }
        return ret;
    }
    ll term(state &cur) {
        ll ret = factor(cur);
        while (true) {
            if (*cur == '*') {
                consume(cur, '*');
                ret *= factor(cur);
            } else if (*cur == '/') {
                consume(cur, '/');
                ret /= factor(cur);
            } else {
                break;
            }
        }
        return ret;
    }
    ll factor(state &cur) {
        if (*cur == '(') {
            consume(cur, '(');
            ll ret = expr(cur);
            consume(cur, ')');
            return ret;
        } else {
            return number(cur);
        }
    }
    ll number(state &cur) {
        ll ret = 0;
        while (isdigit(*cur)) {
            ret *= 10;
            ret += *cur - '0';
            ++cur;
        }
        return ret;
    }
};

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