log_recap.md

Log and Generation Recap

What stage is this at?

Right now, the generator is capable of creating nearly ready javascript on the calc example. The run_trm wrap has been removed from this branch but a single make tests in js_of_ocaml-advlog generates navig.html ready code that just needs to be included.

What's missing?

In the immediate, the if then else pattern in generated javascript doesn't have according return call logging. This can be tested in the tests/mylist.ml example. The generation and updating of ctx inside of a function is also incorrect (in some instances): It would be best to have differently named contexts, ie:

> [A] - representation of the variables in context
let A':=
	match A return attributes with
    | attributes_data_of Ad =>
>    [A, Ad]
        attributes_accessor_of_attributes_data Ad
    | attributes_accessor_of Aa =>
>    [A, Aa]
        attributes_data_of_attributes_accessor Aa
    end 
in
>[A, A']
...

In this example, we would be accidentally adding Ad and Aa to the context outside of the let because of our use of a single ctx name. Multi names can be implemented at any level, the easiest being js_of_ast where we still have information as to what context we are stepping into and out of, then sending a generated ctx name to the logger to use.

Adding new logging information

js_of_ast notifies the logger where it wants a "log context" via a call to L.log_line which takes a string and a list of ctx_operation. These operations are defined twice inside log.ml. Both need to be identical. First occurence is line 34.

These contexts will then get recorded and signalled in a generated line via a token (form: |<number>|). log_line searches for a new line or break, which may not exist yet in a string in the OCaml Print Format.

The context must then be matched inside the add_line aux recursive function, which steps through each token list/line pair and completes the action the token is defined to do inside the following match. The catchall skips any non matched tokens.

The final string is reconstructed via a Buffer, so add your logging lines in the same manner, ie:

    | Exit ->
        (* Log exit of a function *)
        Buffer.add_string buf ("\n" ^ pad ^ "log_custom({line:" ^ string_of_int (i + 1) ^ ", type: \"exit\"});");
        aux i ((tks, str) :: xs)

It doesn't matter if the context doesn't also add the original string back in the buffer, as long as you call aux recursively with the same i and the remaining tokens. You can also modify the original string by sending the modified version instead of the str seen in the example above.