character A_upper_calltype A_upper_input(bool writeback, character c, buffer& ib) {
if (writeback) {
ib.push_front(c);
return 0;
} else {
if (ib.size() > 0) return ib.pop_front();
return (character)fgetc(stdin);
}
}
// ni stands for "next int".
int ni(buffer& buf)
{
int i = atoi(buf.front().c_str());
if (i == 0)
for(char ch : buf.front())
if (!isdigit(ch))
error("Expected number, found \"" +
buf.front() + "\".");
buf.pop_front();
return i;
}
// ns stands for "next std::string".
std::string ns(buffer& buf)
{
std::string s = buf.front();
buf.pop_front();
return s;
}
// nch stands of "next char".
char nch(buffer& buf)
{
char ch = (buf.front()[0]);
buf.pop_front();
return ch;
}