Syntax for cartodb.pattern property setting in config file

[mskyttner]

We'd like to make a setting to change the default value of the "cartodb.pattern" URL pattern that is used for the base layers of the front end Google map and we found this indicating that we should be able to set it in a config file:

https://github.com/AtlasOfLivingAustralia/ala-collectory/blob/master/grails-app/conf/Config.groovy#L97

What is the syntax to use to achieve the following string once it hits the javascript:

//cartodb-basemaps-${s}.global.ssl.fastly.net/light_nolabels/${z}/${x}/${y}.png

Ie we remove the http part in the default setting in order to use the default protocol whatever it is and we want to escape the $ (if needed).... Tried a couple of combinations with single quoted strings, no quoting and a slash-dollar style but it seems the dollars get mangled in all these attempts. Is there a groovy syntax for escaping dollar signs we should utilize? Double quoting? Double slashing to have a string literal that retains the dollar signs?

[mskyttner]

We ended up using this syntax and it seems to work:

cartodb.pattern=//cartodb-basemaps-\$\{s\}.global.ssl.fastly.net/light_nolabels/
\$\{z\}/\$\{x\}/\$\{y\}.png