Shopify/liquid — pull request #369 by benstein (2014-06-19 15:53:07+00:00)
Title: Allow variables to start with digits

Contexts may have key names that start with digits, but liquid templates don't support identifier names that start with digits e.g. ```{% if 2013_revenue > 100 %}```
This change to NUMBER_LITERAL regex checks that a number is on a word boundary. If not, it will be considered an identifier