booleanLiteral function
Implementation
Parser<Literal> booleanLiteral() {
final wordBoundary = pattern('a-zA-Z0-9_-').not();
return ((string('true') | string('false')) & wordBoundary.and())
.map((value) {
final keyword = value[0] as String;
return Literal(keyword == 'true', LiteralType.boolean);
})
.labeled('booleanLiteral');
}