spawn task for read and write to lang process

plugins/shrs_mux/Cargo.toml

@@ -15,3 +15,4 @@ repository.workspace = true
 [dependencies]
 shrs = { path = "../../crates/shrs", version = "^0.0.3" }
 clap = { version = "4.1", features = ["derive"] }
+tokio = { version = "1.35", features = ["full"] }

plugins/shrs_mux/src/lang/bash.rs

@@ -0,0 +1,86 @@
+use std::{
+    cell::RefCell,
+    collections::HashMap,
+    fmt::format,
+    io::{BufRead, BufReader, Read, Write},
+    ops::Add,
+    os::unix::process::ExitStatusExt,
+    process::{Child, ChildStderr, ChildStdin, ChildStdout, Command, ExitStatus, Stdio},
+    sync::Arc,
+};
+
+use shrs::{
+    lang::{Lexer, Token},
+    prelude::*,
+};
+
+use crate::{
+    interpreter::{read_err, read_out},
+    MuxState,
+};
+
+pub struct BashLang {
+    instance: RefCell<Child>,
+}
+
+impl BashLang {
+    pub fn new() -> Self {
+        Self {
+            instance: RefCell::new(
+                Command::new("bash")
+                    .stdin(Stdio::piped())
+                    .stdout(Stdio::piped())
+                    .stderr(Stdio::piped())
+                    .spawn()
+                    .expect("Failed to start bash process"),
+            ),
+        }
+    }
+}
+
+impl Lang for BashLang {
+    fn eval(
+        &self,
+        sh: &Shell,
+        ctx: &mut Context,
+        rt: &mut Runtime,
+        cmd: String,
+    ) -> shrs::anyhow::Result<CmdOutput> {
+        let mut instance = self.instance.borrow_mut();
+        let stdin = instance.stdin.as_mut().expect("Failed to open stdin");
+
+        let cd_statement = format!("cd {}\n", rt.working_dir.to_string_lossy());
+
+        stdin
+            .write_all(cd_statement.as_bytes())
+            .expect("unable to set var");
+
+        for (k, v) in rt.env.iter() {
+            let export_statement = format!("export {}={:?}\n", k, v);
+            stdin
+                .write_all(export_statement.as_bytes())
+                .expect("unable to set var");
+        }
+        stdin
+            .write_all((cmd + ";echo $?'\x1A'; echo '\x1A' >&2\n").as_bytes())
+            .expect("Bash command failed");
+
+        let stdout_reader =
+            BufReader::new(instance.stdout.as_mut().expect("Failed to open stdout"));
+        let status = read_out(ctx, stdout_reader)?;
+
+        let stderr_reader =
+            BufReader::new(instance.stderr.as_mut().expect("Failed to open stdout"));
+        read_err(ctx, stderr_reader)?;
+
+        Ok(CmdOutput::new(status))
+    }
+
+    fn name(&self) -> String {
+        "bash".to_string()
+    }
+
+    fn needs_line_check(&self, cmd: String) -> bool {
+        false
+    }
+}