I'm saying this after decades of reading language descriptions that start with a huge blob of formal grammar in BNF or some other CFG format, then exposition about what the blob means, and then only much much later, some full examples often without examples of how the examples would be parsed by the grammar that was just introduced.
Sure, given enough practice you can learn to read this, sort of. But it's a gigantic and needless pain in the ass, for no real gain. So of course what you (I?) learn to do after you've read a few of these is to skip past all the grammar stuff and look for the examples, which you then try to parse in your head while consulting the grammar stuff whenever you're confused.
It'd be much more straightforward to present a bunch of examples first, in such a way that you can see quickly and easily how each component of the example would be parsed. Have the full grammar and description in an appendix that's easy to consult if needed. I'm pretty sure both beginners and experts would benefit from this way of writing such things.