typedef enum {
    TYPE_NONE,
    TYPE_VOID,
    TYPE_BOOL,

    TYPE_CHAR,
    TYPE_SCHAR,
    TYPE_UCHAR,
    TYPE_SHORT,
    TYPE_USHORT,
    TYPE_INT,
    TYPE_UINT,
    TYPE_LONG,
    TYPE_ULONG,
    TYPE_LLONG,
    TYPE_ULLONG,

    TYPE_FLOAT,
    TYPE_DOUBLE,
    TYPE_LDOUBLE,

    TYPE_POINTER,
    TYPE_ARRAY,
    TYPE_FUNCTION,

    TYPE_STRUCT,
    TYPE_UNION,
    TYPE_ENUM,
} Type_Kind;

typedef struct Type Type;
struct Type {
    Type_Kind kind;
    int size;
    int align;
    Type *base;
};

typedef enum Ast_Kind {
    AST_NONE,
    AST_ERROR,
    AST_PROGRAM,
    AST_INT,
    AST_UNARY,
    AST_BINARY,

    AST_FUNCTION,
    AST_BLOCK,

} Ast_Kind;

typedef struct Ast Ast;
struct Ast {
    Ast_Kind kind;
    Token *pos;

    Ast *first;
    Ast *last;

    union {
        uint64_t u;
        struct {
            Token_Kind op;
            Ast *l;
            Ast *r;
        };
        char *error;
    };
};

Ast *create_ast(Token *token, Ast_Kind kind) {
    Ast *result = calloc(1, sizeof(Ast));
    result->pos = token;
    result->kind = kind;
    return result;
}

Ast *create_binary_expr(Token *token, Token_Kind op, Ast *left, Ast *right) {
    Ast *result = create_ast(token, AST_BINARY);
    result->op = op;
    result->l = left;
    result->r = right;
    return result;
}

Type base_type_int = {TYPE_INT, .size = sizeof(int), .align = __alignof(int)};
Type *type_int = &base_type_int;