Option<Term> term(TokenStream& tokens) {
Option<Term> current = singleTerm(tokens);
if (current.exists()) {
while (tokens.good() && tokens->type != Token::CLOSE_BRACKET) {
Option<Term> next = singleTerm(tokens);
if (next.exists()) {
current = Option<Term>(applicationTerm(*current, *next));
} else return next;
}
return current;
} else return current;
}
Option<Term> lambdaTerm(TokenStream& tokens) {
assert(tokens->type == Token::LAMBDA);
tokens.advance();
if (tokens->type == Token::IDENTIFIER) {
string id = tokens->identifierValue;
tokens.advance();
Option<Term> body = term(tokens);
if (body.exists()) {
return Option<Term>(lambdaTerm(id, *body));
} else return body;
} else return errorTerm("expected identifier");
}
bool run(istream& source, istream& /*in*/, ostream& out, ostream& err,
const InterpreterSettings& settings) {
bool ok = true;
while (ok && source.good()) {
if (settings.interactive) out << "> ";
string line;
getline(source, line, ';');
Option<Term> term = evalLine(line);
if (term.exists()) {
err << *term << endl;
} else {
err << "[Error] eval fail... " << term.errorMessage() << endl;
ok = false;
}
}
return ok;
}
