Implement a command to inspect Jelly files

[Ostrzyciel]

Something like jelly-cli rdf inspect <input-file> or read from stdin

Would respond with a human-readable summary of what the stream is:

• Delimited or not
• Frame count
• Total row count
• Stream options (if present) or a message warning that they are not present
• Total statement (triple or quad) count

Later we can tack on more statistics about lookups and so on.

[johnslavik]

Here's a request from me.
User story:

As a Jelly implementer, I'd like to see how many rows of what kind were sent in each frame.
For checking how stream options interact with my implementation, I need them included in the report.

I have an instinct that a very wise thing to do would be to produce the output in the human-friendly format YAML, so that these statistics can be processed automatically, whenever such need arises.

Here's an example:

stream_options:
  physical_type: 1
  generalized_statements: 1
  rdf_star: 1
  max_name_table_size: 128
  max_prefix_table_size: 16
  max_datatype_table_size: 16
  logical_type: 1
  version: 1

total_frames: ...  # redundant, but can be helpful

frames:
# frame 0
- name: 34
  options: 1
  prefix: 80
  triple: 75

It would be very useful to include frame numbers in comments, unless you have a YAML library without support for round-trip serialization, then it's not that important. You can always add a property called _number.

This would be a decent addition for debugging.

[Ostrzyciel]

YAML sounds like a good idea. But, last time I had to do something with a YAML lib in Scala, I just gave up and wrote a few methods on my own xd not sure how it looks right now