improve output formatting

firmware/src/command_parser.rs

@@ -1,3 +1,4 @@
+use core::fmt;
 use nom::{
     IResult,
     branch::alt,
@@ -39,6 +40,27 @@ impl From<ParseIntegerError> for Error {
     }
 }
 
+impl fmt::Display for Error {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+        match self {
+            Error::Incomplete =>
+                "incomplete input".fmt(fmt),
+            Error::UnexpectedInput(c) => {
+                "unexpected input: ".fmt(fmt)?;
+                c.fmt(fmt)
+            }
+            Error::Parser(e) => {
+                "parser: ".fmt(fmt)?;
+                (e as &dyn core::fmt::Debug).fmt(fmt)
+            }
+            Error::ParseInteger(e) => {
+                "parsing number: ".fmt(fmt)?;
+                e.fmt(fmt)
+            }
+        }
+    }
+}
+
 #[derive(Debug, Clone)]
 pub enum ShowCommand {
     ReportMode,

firmware/src/main.rs

@@ -260,10 +260,10 @@ fn main() -> ! {
                         Command::Quit =>
                             socket.close(),
                         Command::Report(mode) => {
-                            let _ = writeln!(socket, "Report mode: {:?}", mode);
+                            let _ = writeln!(socket, "Report mode: {}", mode);
                         }
                         Command::Show(ShowCommand::ReportMode) => {
-                            let _ = writeln!(socket, "Report mode: {:?}", session.report_mode());
+                            let _ = writeln!(socket, "Report mode: {}", session.report_mode());
                         }
                         Command::Show(ShowCommand::Pid) => {
                             let _ = writeln!(socket, "PID settings");

firmware/src/session.rs

@@ -1,4 +1,5 @@
 use core::ops::Deref;
+use core::fmt;
 use super::command_parser::{Command, Error as ParserError};
 
 const MAX_LINE_LEN: usize = 64;
@@ -60,6 +61,17 @@ pub enum ReportMode {
     Continuous,
 }
 
+impl fmt::Display for ReportMode {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+        match self {
+            ReportMode::Off => "off",
+            ReportMode::Once => "once",
+            ReportMode::Continuous => "continuous",
+            _ => "<INVALID>",
+        }.fmt(fmt)
+    }
+}
+
 pub enum SessionOutput {
     Nothing,
     Command(Command),