conch-runtime-pshaw 0.1.6

A library for evaluating/executing programs written in the shell programming language.
Documentation 
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use crate::env::VariableEnvironment;
use crate::eval::{double_quoted, Fields, WordEval, WordEvalConfig, WordEvalResult};
use conch_parser::ast::Word;
use futures_core::future::BoxFuture;
use std::borrow::Borrow;

impl<T, W, E> WordEval<E> for Word<T, W>
where
    T: Send + Sync + Clone,
    W: Send + Sync + WordEval<E>,
    W::EvalResult: 'static + Send + Sync + From<T>,
    W::Error: Send,
    E: ?Sized + Send + VariableEnvironment<Var = W::EvalResult>,
    E::VarName: Borrow<String>,
{
    type EvalResult = W::EvalResult;
    type Error = W::Error;

    fn eval_with_config<'life0, 'life1, 'async_trait>(
        &'life0 self,
        env: &'life1 mut E,
        cfg: WordEvalConfig,
    ) -> BoxFuture<'async_trait, WordEvalResult<Self::EvalResult, Self::Error>>
    where
        'life0: 'async_trait,
        'life1: 'async_trait,
        Self: 'async_trait,
    {
        match self {
            Word::Simple(w) => w.eval_with_config(env, cfg),
            Word::SingleQuoted(s) => {
                let ret = Fields::Single(W::EvalResult::from(s.clone()));
                Box::pin(async move { Ok(box_up(ret)) })
            }
            Word::DoubleQuoted(d) => Box::pin(double_quoted(d, env)),
        }
    }
}

// Not sure why we need this as a stand alone function, but it seems like the
// compiler gets confused if we have two nested `Box::pin` calls.
fn box_up<T>(t: T) -> BoxFuture<'static, T>
where
    T: 'static + Send,
{
    Box::pin(async move { t })
}