Little improvements in debugging

.vscode/debugging.billo.json

@@ -0,0 +1 @@
+{}

.vscode/greetings.txt

@@ -0,0 +1 @@
+Hello world!

.vscode/launch.json

@@ -9,7 +9,7 @@
             "type": "lldb",
             "request": "launch",
             "program": "${workspaceFolder}/billo/target/debug/billo",
-            "args": [],
+            "args": ["run", "--config", "${workspaceFolder}/.vscode/debugging.billo.json"],
             "cwd": "${workspaceFolder}"
         }
         // {

.vscode/tasks.json

@@ -18,8 +18,12 @@
         {
             "id": "args",
             "description": "List of arguments",
-            "default": "--help",
-            "type": "promptString"
+            "default": "run --config ${workspaceFolder}/.vscode/debugging.billo.json",
+            "type": "pickString",
+            "options": [
+                "--help",
+                "run --config ${workspaceFolder}/.vscode/debugging.billo.json"
+            ]
         }
     ]
 }

billo/lib/err.rs

@@ -0,0 +1,34 @@
+use std::{
+	fmt::{self, Display},
+	io, result,
+};
+
+pub type Feedback = result::Result<(), Msg>;
+pub type Result<T> = result::Result<T, Msg>;
+
+#[derive(Debug)]
+pub struct Msg(String);
+
+impl Display for Msg {
+	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+		self.0.fmt(f)
+	}
+}
+
+impl From<io::Error> for Msg {
+	fn from(e: io::Error) -> Msg {
+		Msg(format!("{}", e))
+	}
+}
+
+impl From<String> for Msg {
+	fn from(s: String) -> Msg {
+		Msg(s)
+	}
+}
+
+impl From<&str> for Msg {
+	fn from(s: &str) -> Msg {
+		Msg(s.to_owned())
+	}
+}

billo/lib/mod.rs

@@ -1 +1,2 @@
+mod err;
 pub mod running;

billo/lib/running.rs

@@ -1,15 +1,35 @@
+use crate::err;
+use std::fmt::Write as _;
 use std::fs;
 use std::path::Path;
 use std::path::PathBuf;
 
+fn eval_input(config_filepathbuf: &PathBuf) -> err::Feedback {
+	let mut err_msg: String = String::new();
+
+	if !config_filepathbuf.is_file() {
+		writeln!(
+			err_msg,
+			"Expected config as file, but dir is provided: {}",
+			config_filepathbuf.to_string_lossy()
+		)
+		.unwrap();
+	}
+
+	if err_msg.is_empty() {
+		Ok(())
+	} else {
+		Err(err::Msg::from(err_msg))
+	}
+}
+
 pub fn run(config_filepathbuf: PathBuf) {
-	let config_dirpathbuf: &Path = {
-		if config_filepathbuf.is_file() {
-			config_filepathbuf.parent().expect("Expected a parent")
-		} else {
-			&config_filepathbuf
-		}
-	};
+	if let Err(err) = eval_input(&config_filepathbuf) {
+		println!("{}", err);
+		std::process::exit(1)
+	}
+
+	let config_dirpathbuf: &Path = config_filepathbuf.parent().expect("Expected a parent");
 
 	fs::write(config_dirpathbuf.join("greetings.txt"), "Hello world!")
 		.expect("Unable to write file");