main.cpp

#include "Grammar.hpp"

#include <iostream>
#include <cstdlib>

using CXGram::Grammar;
using CXGram::Rule;
using CXGram::WRule;

#define DEFINE_SYMBOL( _n_, _is_term_, _text_ ) \
    struct _n_ { \
        static constexpr const char * Name = _text_; \
        static constexpr bool IsTerminal = _is_term_; \
    }

#define DEFINE_TERM( _n_, _text_ )    DEFINE_SYMBOL( _n_, true, _text_ )
#define DEFINE_NONTERM( _n_, _text_ ) DEFINE_SYMBOL( _n_, false, _text_ )

DEFINE_NONTERM(A, "A");
DEFINE_NONTERM(B, "B");
DEFINE_NONTERM(C, "C");
DEFINE_NONTERM(D, "D");
DEFINE_NONTERM(E, "E");

DEFINE_TERM(a, "a");
DEFINE_TERM(b, "b");
DEFINE_TERM(c, "c");
DEFINE_TERM(d, "d");
DEFINE_TERM(e, "e");

using Toy = Grammar<
    A,
    Rule<A, A, B, C, D, E>,
    Rule<A, C, D, E>,
    Rule<B, b>,
    Rule<B, B, E, C>,
    Rule<C, c>,
    Rule<C, c, d, c, d, c>,
    Rule<C, D, E>,
    Rule<D, d>,
    Rule<D, B, E>,
    Rule<E, e>
>;

DEFINE_NONTERM(Expr, "E");
DEFINE_NONTERM(Term, "T");
DEFINE_NONTERM(Factor, "F");
DEFINE_NONTERM(Digits, "<#s>");
DEFINE_NONTERM(Digit, "<#>");

DEFINE_TERM(LParen, "(");
DEFINE_TERM(RParen, ")");

DEFINE_TERM(Plus, "+");
DEFINE_TERM(Minus, "-");

DEFINE_TERM(Times, "*");
DEFINE_TERM(Div, "/");

DEFINE_TERM(n0, "0");
DEFINE_TERM(n1, "1");
DEFINE_TERM(n2, "2");
DEFINE_TERM(n3, "3");
DEFINE_TERM(n4, "4");
DEFINE_TERM(n5, "5");
DEFINE_TERM(n6, "6");
DEFINE_TERM(n7, "7");
DEFINE_TERM(n8, "8");
DEFINE_TERM(n9, "9");

using WeightedMath = Grammar<
    Expr,

    WRule<6, Expr, Term>,
    WRule<2, Expr, Expr, Plus, Term>,
    WRule<2, Expr, Expr, Minus, Term>,

    WRule<6, Term, Factor>,
    WRule<2, Term, Term, Times, Factor>,
    WRule<2, Term, Term, Div, Factor>,

    WRule<8, Factor, Digits>,
    WRule<2, Factor, LParen, Expr, RParen>,

    WRule<4, Digits, Digit>,
    WRule<6, Digits, Digits, Digit>,

    WRule<0, Digit, n0>,
    WRule<0, Digit, n1>,
    WRule<1, Digit, n2>,
    WRule<1, Digit, n3>,
    WRule<1, Digit, n4>,
    WRule<0, Digit, n5>,
    WRule<1, Digit, n6>,
    WRule<0, Digit, n7>,
    WRule<1, Digit, n8>,
    WRule<1, Digit, n9>
>;

template<typename G, size_t I>
void print() {
    if constexpr (I > 1)
        print<G, I - 1>();

    std::cout << I << ": " << G::template Production<I> << '\n';
}

int main() {
    std::cout << "toy:\n";
    print<Toy, 5>();

    std::cout << "math:\n";
    print<WeightedMath, 15>();
}