Split main.rs into lib.rs and bin/scryer-prolog.rs #838
Conversation
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Impressive! Thank you a lot for working on this! I hope this makes it possible and attractive to embed Scryer Prolog more easily in Rust applications. |
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@triska I think further work is necessary to make the library useful but this will at least get the work started |
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I'm not sure allowing The crate |
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The signal handler is now moved to the binary. Should I move the lib to its own package so that dependencies can be specified independently of the bin or is this ok? Instead of adding the |
Crate like I'm sorry, I should have reviewed everything. This should be the last remark, the workaround introduced by |
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Removed the commit that introduced the workaround and reverted the removal of |
* makes most pub things in src/ pub(crate) as not to expose things accidentally
* only those things needed by src/bin/scryer-prolog.rs and tests/scryer.rs
should be pub
* split src/main.rs into src/lib.rs and src/bin/scryer-prolog.rs
* add tests folder and run most of the files in src/tests with cargo test
added bytes method to Stream in src/machine/streams.rs to check if stdout is as expected
only commenting out the unused variant as `OptArgIndexKeyType` as it appears to mirror `OptArgIndexKey` and there List is not unused so this appears to be not yet used rather than obsolete
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Rebased to fix conflicts |
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Great, thanks very much! |
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I am watching this work closely, I have naively tried to embed Scryer in my own Rust program (in a tokio task) and would like to report the following challenges:
I'm very thankful that such a comprehensive prolog interpreter is built in pure Rust, and I'm on my first handful of hours working with Scryer, so please understand my feedback through that lens. Perhaps I should try again with this branch, and report my findings. Pseudo reproduction how I am trying to embed scryerThe reasoning behind using Tokio this way is that my parser will constantly receive user input in a prolog-like language, which will be parsed, and canonicalized and fed to a prolog engine (Scryer, in this evolution), which will then be queried, so the pipeline goes struct Engine {
parser_edits: Sender<String>,
prolog_expr: Sender<String>,
stop: tokio::sync::broadcast::Sender<()>,
stopper: tokio::sync::broadcast::Receiver<()>,
}
impl Engine {
pub fn new() -> Result<Arc<Self>, Error> {
let (stop, stopper) = tokio::sync::broadcast::channel(16);
let (parser_edits, edit_rx) = tokio::sync::mpsc::channel(16);
let (prolog_exprs, prolog_rx) = tokio::sync::mpsc::channel(16);
let Engine = Self {
parser_edits,
prolog_exprs,
stop,
stopper,
};
let Engine = Arc::new(Engine);
tokio::task::spawn(Engine.clone().start_parser(stop.subscribe(), edit_rx));
tokio::task::spawn(Engine.clone().start_wam(stop.subscribe(), prolog_rx));
Ok(Engine)
}
async fn shutdown(self: Arc<Self>) -> Result<(), Error> {
self.stop.send(());
// ..snip..
Ok(())
}
async fn start_parser(
self: Arc<Self>,
mut stop: tokio::sync::broadcast::Receiver<()>,
mut rx: Receiver<String>,
) {
// .. snip ..
loop {
tokio::select! {
_ = stop.recv() => {
// ..snip..
break
}
Some(msg) = rx.recv() => {
// ..snip..
}
}
}
}
async fn start_wam(
self: Arc<Self>,
mut stop: tokio::sync::broadcast::Receiver<()>,
mut rx: Receiver<String>,
) {
let file = "src/tests/helloworld.pl";
let input = Stream::from("");
let output = Stream::from(String::new());
let error = Stream::from(String::new());
let mut wam = self.tracer.in_span("initializing wam", |_cx| {
// https://github.com/mthom/scryer-prolog/blob/master/tests/scryer/helper.rs
Machine::new(input, output.clone(), error)
});
self.tracer.in_span("parsing test file", |_cx| {
wam.load_file(
file.into(),
Stream::from(
std::fs::read_to_string(AsRef::<std::path::Path>::as_ref(file)).unwrap(),
),
);
});
loop {
tokio::select! {
_ = stop.recv() => {
println!("stopping wam because stop signal received");
break
}
Some(msg) = rx.recv() => {
println!("received tokens = {:?}", msg);
}
}
}
println!("wam stopped");
}
}
let e = Engine.new
e.shutdown(); |
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@leehambley: Thank you a lot for trying this! Could you please try this with the current Please see the recent announcement and its discussion. |
As requested by Issues #225, #570 and #765 this makes it possible to use scryer-prolog as a library,
currently this only exposes a minimal API to get the binary and some added tests working.