getTokenErrorDisplay method
How should a token be displayed in an error message? The default is to display just the text, but during development you might want to have a lot of information spit out. Override in that case to use t.toString() (which, for CommonToken, dumps everything about the token). This is better than forcing you to override a method in your token objects because you don't have to go modify your lexer so that it creates a new Java type.
Implementation
String getTokenErrorDisplay(Token? t) {
if (t == null) return '<no token>';
var s = getSymbolText(t);
if (s == null) {
if (getSymbolType(t) == Token.EOF) {
s = '<EOF>';
} else {
s = '<${getSymbolType(t)}>';
}
}
return escapeWSAndQuote(s);
}