@Override
public boolean eof() {
try {
return currentToken() == null && scanner.eof();
} catch (IOException e) {
throw new ParseException(e.getMessage(), scanner.currentParseOffset(), e);
}
}
@Override
public int currentParseOffset() {
Token tok = currentToken();
if (tok == null) {
return scanner.currentParseOffset();
}
return tok.getParseOffset();
}
private Token currentToken() {
if (tokens.isEmpty()) {
try {
if (scanner.eof()) {
return null;
}
parseNextTokens();
} catch (IOException e) {
throw new ParseException(e.getMessage(), scanner.currentParseOffset(), e);
}
if (tokens.isEmpty()) {
return null;
}
}
return tokens.get(0);
}
@Override
public Token read(TokenType type) {
if (!peek().hasType(type)) {
throw new ParseException(
"Expected token of type " + type + " but got " + peek().getType(),
scanner.currentParseOffset());
}
return read();
}
private void parseNextTokens() throws IOException {
int startOffset = scanner.currentParseOffset();
buffer.setLength(0);
outer_loop:
while (!scanner.eof() && tokens.isEmpty()) {
char c = scanner.read();
switch (c) {
case '=':
bufferToTokens(startOffset, true);
tokens.add(new Token(c, scanner.currentParseOffset() - 1, TokenType.EQUALS));
return;
case ' ': /* whitespace */
case '\t':
bufferToTokens(startOffset, true);
if (skipWhitespace) {
while (!scanner.eof()) {
c = scanner.peek();
if (c != ' ' && c != '\t') {
continue outer_loop;
}
scanner.read();
}
return;
}
startOffset = scanner.currentParseOffset() - 1;
buffer.append(c);
outer:
while (!scanner.eof()) {
c = scanner.peek();
switch (c) {
case ' ':
case '\t':
buffer.append(scanner.read());
break;
default:
break outer;
}
}
tokens.add(new Token(buffer, startOffset, TokenType.WHITESPACE));
return;
case '(':
bufferToTokens(startOffset, true);
tokens.add(new Token(c, scanner.currentParseOffset() - 1, TokenType.PARENS_OPEN));
return;
case ')':
bufferToTokens(startOffset, true);
tokens.add(new Token(c, scanner.currentParseOffset() - 1, TokenType.PARENS_CLOSE));
return;
}
buffer.append(c);
if (bufferToTokens(startOffset, false)) {
return;
}
}
bufferToTokens(startOffset, true);
}
private void checkEOF() {
if (eof()) {
throw new ParseException("Already at EOF", scanner.currentParseOffset());
}
}