Enum Feed 

pub enum Feed<T> {
    Complete {
        entry: Entry,
        value: T,
    },
    Incomplete,
    Empty,
}

The outcome of feeding one line to a Session.

A host’s read loop matches on it: evaluate and print on Complete, show a continuation prompt on Incomplete, and simply prompt again on Empty.

Examples

use repl_lang::{Feed, Session, Status};

let mut session = Session::new();
let pipeline = |input: repl_lang::Input<'_>| {
    let open = input.text().matches('{').count();
    let close = input.text().matches('}').count();
    if open > close { Status::Incomplete } else { Status::Complete(input.text().len()) }
};

let mut transcript = Vec::new();
for line in ["", "f {", "  x", "}"] {
    let prompt = if session.is_pending() { "... " } else { ">>> " };
    match session.feed(line, pipeline)? {
        Feed::Complete { entry, value } => {
            transcript.push(format!("{prompt}{line}  -> entry {} ({value} bytes)", entry.number()));
        }
        Feed::Incomplete => transcript.push(format!("{prompt}{line}")),
        Feed::Empty => transcript.push(prompt.trim_end().to_owned()),
    }
}
assert_eq!(transcript, [">>>", ">>> f {", "...   x", "... }  -> entry 1 (10 bytes)"]);

Variants

Complete

The pipeline accepted the entry. It is now committed to the session’s source map, so diagnostics carrying its spans render against Session::sources.

Fields

entry: Entry

Where the committed entry lives.

value: T

What the pipeline returned in Status::Complete.

Incomplete

The pipeline needs more input. The line is kept, and the next one is appended to it.

Empty

The line was blank and no entry was in progress, so there was nothing to evaluate. The pipeline was not called and no entry number was used.

Trait Implementations

impl<T: Clone> Clone for Feed<T>

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T: Copy> Copy for Feed<T>

impl<T: Debug> Debug for Feed<T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<T: Eq> Eq for Feed<T>

impl<T: Hash> Hash for Feed<T>

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl<T: PartialEq> PartialEq for Feed<T>

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl<T: PartialEq> StructuralPartialEq for Feed<T>