parseWith method
Implementation
Statement parseWith() {
int? start = token!.startOffset;
int? line = token!.line;
assert(token!.text == 'with');
consume(Token.NAME);
consume(Token.LPAREN);
Expression exp = parseExpression();
consume(Token.RPAREN);
Statement body = parseStatement();
return WithStatement(exp, body)
..start = start
..end = endOffset
..line = line;
}