If one was to need a config file for software they've written, what do people typically use with Janet
I see there is support for toml and json. No idea about yaml or ini. I really dislike json for configuration files, but I have used json with Janet for talking to other processes so I know that works well. XML and alike are most definitely a no go.
I see there is support for toml and json. No idea about yaml or ini. I really dislike json for configuration files, but I have used json with Janet for talking to other processes so I know that works well. XML and alike are most definitely a no go.
very good question about which I am not sure, but it is a Janet code at the end, so I guess you can
hmmm, since it's janet code, I guess the major diff between it and regular janet code is it only allows returning values? as in, protected from arbitrary code exec?
well I am reading the config this way:
(def file-conf ((compile (parse (slurp file))))) so definitely executing the code
but I guess you can protect it easily
depending on what you want, you don't need to do
compile iiuc: https://github.com/janet-lang/janet/blob/master/test/suite0008.janet#L297-L298
Indeed. to be frank, I am not sure why I do in the snippet I have sent :-)
well I highly recommend it, especially to someone already deep in Janet as I feel you are
llmII: here's a taste of what you can do with parser/* stuff: https://github.com/sogaiu/janet-editor-elf/blob/master/janet-editor-elf/delims.janet#L16-L53
this is what i use to find missing delimiters in "partial" code
I'll probably want the parser api, if I could somehow parse multiple blocks, or I guess I could just wrap the entire file in
[] to get it all back as an array of toplevel values
parsing multiple things should be doable too
I'm guessing the full parser API would be needed for the multiple things?
unless you wrap like you described
that's why my first thought was array-wrapping a string, keeps things simple to be just a single parse call
yes :)
hehehe, I thought you were about to mention an edge case where doing so means breaking everything lol
hehe, I see, still getting used to matrix, and tab complete selection, good to know they're both you
anyway, this part of Janet is the one I like a lot. Not that I am using it that often, but there is something calming in the knowledge that it exists :-). And is not that hard to use, when needed
2 replies
pp: got to thinking about it, the context stuff, saw an example of that somewhere actually, very useful, as to do-file... could spawn it in another fiber with a deadline and between limiting context so they basically only get def/var and specials and maybe something you want to insert, and setting a deadline (no infinite while loops), can possibly prevent that
by prevent that, I mean, prevent arbitrary code exec
I'm unsure if the deadline for a spawned coroutine will work if all that is done is blocking actions
ev/with-deadline won't work for that, as I feared, might be better to just start a process to read the config, or start a thread really
(ev/with-deadline 5 (ev/thread (fn [] (while true ())))) works 😁
only issue I guess is there's no way to kill a thread like that that I know of
that said, I'd guess dofile and the like are ok where things can be trusted, but using the parser is the best bet for stuff that the user supplies and you don't want to trust... not sure what to do about the ability to have hung threads if someone inserts a "while true" loop, sort of I guess want a way to say "stop running the script if it takes too long", processes have better support in this case than threads, since such can be killed if it runs away
oh well, configuration file parsing can be done with parse, doing it with nice error messages can be figured out later, just have to think on how to use the parser to do multiple values instead of array-wrapping possibly
possibly of interest? https://github.com/janet-lang/janet/blob/master/src/boot/boot.janet#L3512-L3522
that's of interest indeed, if I could prohibit
fn defn defmacro and variants that'd pretty much make flycheck do great for checking for errors without having to worry about arbitrary execution