IntegerType
parse_ascii_integer(TokenStream & stream) {
if (!stream.peek()) throw std::runtime_error("eof");
if (!ascii_digit_value(*stream.peek())) {
throw std::runtime_error("not at a number!");
}
IntegerType toret = 0;
while (true) {
auto inb = stream.peek();
if (!inb) break;
auto digit_val = ascii_digit_value(*inb);
if (!digit_val) break;
auto oldtoret = toret;
toret = toret * 10 + *digit_val;
if (toret < oldtoret) {
throw std::runtime_error("overflow occured");
}
stream.skip();
}
return toret;
}
void
expect(TokenStream & stream, Token expected) {
auto maybe_token = stream.peek();
if (!maybe_token || *maybe_token != expected) {
throw std::runtime_error("Failed expect");
}
stream.skip();
}
void
skip_token(TokenStream & stream, Token token) {
while (true) {
auto inb = stream.peek();
if (!inb || *inb != token) break;
stream.skip();
}
}
std::vector<typename std::decay<decltype(*std::declval<TokenStream>().peek())>::type>
read_token_vector(TokenStream & stream, opt::optional<Token> term,
opt::optional<size_t> max_amt, bool drop_term = false) {
std::vector<typename std::decay<decltype(*std::declval<TokenStream>().peek())>::type> toret;
for (size_t i = 0; !max_amt || i < *max_amt; ++i) {
auto mB = stream.peek();
if (!mB || (term && *mB == *term)) {
if (drop_term) stream.skip();
break;
}
toret.push_back(*mB);
stream.skip();
}
return toret;
}