如何限制规则在XTEXT中重复的次数？

Question

My language has certain keywords which only accept values of certain length range (say, between 5 and 10 decimal numbers). This id correct:

KeyWord = 01234

This is incorrect:

KeyWord = 1234

I have a rule;

KeyWord:
  'KeyWord' '=' INT+;

How to limit the number of times INT can repeat? This would so much easier if it was a more regexp-like syntax

Answer 1

I would implement this as a validation check instead of trying to fit this in the grammar itself. See http://www.eclipse.org/Xtext/documentation/2_1_0/050-validation.php

This will result in better error recovery and better error messages. It even allows quick-fixes.