Statement *ParserContext::parse_statement() {
Statement *statement = 0;
switch (curtok()->type()) {
case tok_while: {
statement = parse_while();
break;
}
case tok_if: {
statement = parse_if();
break;
}
case tok_return: {
statement = parse_return();
eat_token(tok_semicolon);
break;
}
case tok_def: {
statement = parse_def();
break;
}
default: {
Expression *expression = parse_expression();
if (expression) {
statement = new ExpressionStatement(expression);
eat_token(tok_semicolon);
} else {
throw UnexpectedToken("parse_statement", curtok());
}
break;
}
}
return statement;
}
Status Parser::ConsumeToken(int type) {
ASSIGN_OR_RETURN(auto token, GetNextToken());
if (!token->IsType(type)) {
return UnexpectedToken(*token);
}
return Status();
}
Expression *ParserContext::parse_primary() {
switch (curtok()->type()) {
case tok_word: return parse_word_expression();
case tok_number: return parse_number();
case tok_string: return parse_string();
case tok_paren_start: return parse_paren_expression();
default: throw UnexpectedToken("parse_primary", curtok());
}
}
inline void FileParse::checkComment(std::ifstream& fin) {
char c;
fin.get(c);
// Make sure we are not at eof
if (fin.eof()) return;
// Check what kind of comment this is
if (c=='/') passComment(fin, false);
else if (c=='*') passComment(fin, true);
else throw UnexpectedToken("In checkComment: Token: ["+toStr(c)+"].");
}
StatusOr<std::unique_ptr<Node>> Parser::Parse() {
if (!look_ahead_token_) {
ASSIGN_OR_RETURN(auto token, GetNextToken());
}
// Check for end of input.
if (look_ahead_token_->IsType(Lexer::TYPE_END_OF_INPUT)) {
return UnexpectedToken(*look_ahead_token_);
}
// Parse expression.
return ParseExpression(0);
}
inline void FileParse::getHeading(std::ifstream& fin, string& heading, bool& found) {
char c;
fin.get(c);
bool whitespace = false;
while (!fin.eof()) {
if (c=='{') {
found = true;
return;
}
else if (c==':') {
found = false;
return;
}
else if (c=='\n' || c=='\r' || c==' ') whitespace = true;
else { // Just a regular character. Could be a whitespace
if (whitespace) { // Error
throw UnexpectedToken("In getHeading: Found whitespace.");
}
else heading.push_back(c);
}
// Get the next character
fin.get(c);
}
}
StatusOr<std::unique_ptr<Node>> Parser::ParseInfixToken(
std::unique_ptr<const Token> token, std::unique_ptr<const Node> left) {
return UnexpectedToken(*token);
}
Status Parser::ExpectToken(const Token& token, int type) {
return token.IsType(type) ? Status() : UnexpectedToken(token);
}