js.plated_chunks.expand_tag

value = plated_chunks.expand_tag(v,dat,lastpass)

Do all the magical things that enables a tag to expand, normally we just lookup the value inside dat but a few operators can be applied.

if dat is null then we use data pushed into the namespaces otherwise we will only use data available in dat.

Operators are applied from left to right so we have no precedence besides this.

If we fail to lookup a valid value then we return input string wrapped in delimiters, essentially any values we do not understand will come out of the process unscathed exactly as they went in.

There must be no white space inside {} or we will not process it.

This combined is why we can safely use {} rather than {{}} and any accidental use will survive.