From 77b8c9ec5cf93bcb767af97b11230577d86b55ea Mon Sep 17 00:00:00 2001
From: Milo Turner <iitalics@gmail.com>
Date: Sat, 7 Mar 2020 13:35:03 -0500
Subject: [PATCH] enterprise scale rust

---
 hptp-recv/src/main.rs | 31 +++++++++++++++++++------------
 1 file changed, 19 insertions(+), 12 deletions(-)

diff --git a/hptp-recv/src/main.rs b/hptp-recv/src/main.rs
index 8b1ce00..2cd28ba 100644
--- a/hptp-recv/src/main.rs
+++ b/hptp-recv/src/main.rs
@@ -1,3 +1,5 @@
+use std::str::FromStr;
+
 extern crate hptp;
 
 #[derive(Debug)]
@@ -6,8 +8,17 @@ struct Hostname {
     port: u16,
 }
 
-fn go(hn: Hostname) {
-    println!("ip={}, port={}", hn.ip, hn.port)
+struct InvalidHostnameError;
+
+impl FromStr for Hostname {
+    type Err = InvalidHostnameError;
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        let i = s.find(':').ok_or(InvalidHostnameError)?;
+        Ok(Hostname {
+            ip: s[..i].into(),
+            port: s[i + 1..].parse().map_err(|_| InvalidHostnameError)?,
+        })
+    }
 }
 
 fn usage() {
@@ -15,20 +26,16 @@ fn usage() {
 }
 
 fn parse_args() -> Result<Hostname, ()> {
-    let mut args = std::env::args();
-    let arg = args.nth(1).ok_or(())?;
-    let i = arg.find(':').ok_or(())?;
-    let ip = &arg[..i];
-    let port: u16 = arg[i + 1..].parse().map_err(|_| ())?;
-    Ok(Hostname {
-        ip: ip.into(),
-        port,
-    })
+    std::env::args().nth(1).ok_or(())?.parse().map_err(|_| ())
 }
 
 fn main() {
     match parse_args() {
-        Ok(x) => go(x),
+        Ok(x) => start(x),
         Err(_) => usage(),
     }
 }
+
+fn start(hn: Hostname) {
+    println!("ip={}, port={}", hn.ip, hn.port)
+}