Allow using -m outside of xplr shell for debugging

Also validate the message before passing.

src/cli.rs

@@ -1,5 +1,6 @@
 use crate::app;
 use anyhow::{bail, Context, Result};
+use app::ExternalMsg;
 use serde_json as json;
 use std::fs::File;
 use std::io::{BufRead, BufReader, Write};
@@ -181,19 +182,23 @@ pub fn pipe_msg_in(args: Vec<String>) -> Result<()> {
         bail!("too many arguments")
     }
 
-    let path = std::env::var("XPLR_PIPE_MSG_IN")
-        .context("passing messages in only works inside xplr shell")?;
-
-    let delimiter = fs::read(&path)?
-        .first()
-        .cloned()
-        .context("failed to detect delimmiter")?;
-
-    msg.push(delimiter.try_into()?);
-    File::options()
-        .append(true)
-        .open(&path)?
-        .write_all(msg.as_bytes())?;
+    // Validate
+    let mut msg = json::to_string(&ExternalMsg::try_from(msg.as_str())?)?;
+
+    if let Ok(path) = std::env::var("XPLR_PIPE_MSG_IN") {
+        let delimiter = fs::read(&path)?
+            .first()
+            .cloned()
+            .context("failed to detect delimmiter")?;
+
+        msg.push(delimiter.try_into()?);
+        File::options()
+            .append(true)
+            .open(&path)?
+            .write_all(msg.as_bytes())?;
+    } else {
+        println!("{}", msg);
+    }
 
     Ok(())
 }

src/msg/in_/external.rs

@@ -2,6 +2,8 @@ use crate::{app::Node, input::InputOperation};
 use indexmap::IndexSet;
 use regex::Regex;
 use serde::{Deserialize, Serialize};
+use serde_json as json;
+use serde_yaml as yaml;
 use std::cmp::Ordering;
 
 #[derive(Debug, Clone, Eq, PartialEq, Serialize, Deserialize)]
@@ -1084,17 +1086,20 @@ pub enum ExternalMsg {
 }
 
 impl TryFrom<&str> for ExternalMsg {
-    type Error = serde_yaml::Error;
+    type Error = anyhow::Error;
 
     fn try_from(value: &str) -> Result<Self, Self::Error> {
-        if value.starts_with('!') {
-            serde_yaml::from_str(value)
+        let msg = if let Ok(val) = json::from_str(&value) {
+            val
+        } else if value.starts_with('!') {
+            yaml::from_str(value)?
         } else if let Some((msg, args)) = value.split_once(' ') {
             let msg = format!("!{} {}", msg.trim_end_matches(':'), args);
-            serde_yaml::from_str(&msg)
+            yaml::from_str(&msg)?
         } else {
-            serde_yaml::from_str(value)
-        }
+            yaml::from_str(value)?
+        };
+        Ok(msg)
     }
 }