Where can I find the exact syntax (grammar) for the Wolfram Language? I know it is parsed down to symbols, strings, numbers, operators, and comments -- see e.g. the section on Syntax of
But what are the exact rules for this?
Could you explain a bit more what you mean? I have a suspicion that what you are asking might be a proprietary information.
If you are interested in parsing WL expressions take a look at the open source parser from Wolfram Research.