Minimalistic core for UDL description?

[Jørgen Steensgaard]

I have just started using np++, so this may be a known and solved problem. The UDL of np++ allows us to
modify known language descriptions but I am looking for one that is minimalistic in the sense of known symbols.

{ }, say. In addition perhaps also some widely used notations for constants and definitely a few empty sets of symbol classes – e.g. identifiers, operators, types, special symbols – with means to add user defined symbols.

For the time being I can do with the Java description, which almost fit my bill. A recent example that caused problems were a variant of the following
P{aaa; “bbb”}{…} which I had to rewrite as P({aaa; “bbb”},{…}) to get collapsing correct.