Clap 3.0.0-beta.5

Cargo.toml

@@ -5,7 +5,7 @@ authors = ["Anthony Cicchetti <anthony@anthonycicchetti.com>"]
 edition = "2021"
 
 [dependencies]
-clap = "2.34.0"
+clap = "3.0.0-beta.5"
 day_01 = { path = "./day_01" }
 day_02 = { path = "./day_02" }
 

src/main.rs

@@ -1,32 +1,81 @@
-extern crate clap;
-
-use clap::{arg_enum, clap_app, value_t};
 use std::error::Error;
+use std::fmt::{Debug, Display, Formatter};
 use std::fs::File;
 use std::io::{BufReader, Read};
+use std::str::FromStr;
+
+use clap::{App, AppSettings::ArgRequiredElseHelp, Arg};
 
-arg_enum! {
 #[derive(Debug)]
 enum DaysImplemented {
     Day1,
     Day2,
 }
+
+impl Display for DaysImplemented {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        match self {
+            DaysImplemented::Day1 => {
+                write!(f, "Day 1")
+            }
+            DaysImplemented::Day2 => {
+                write!(f, "Day 2")
+            }
+        }
+    }
+}
+
+impl FromStr for DaysImplemented {
+    type Err = &'static str;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        match s {
+            "Day1" => Ok(DaysImplemented::Day1),
+            "Day2" => Ok(DaysImplemented::Day2),
+            _ => Err("Not any of days implemented"),
+        }
+    }
 }
 
 fn main() -> Result<(), Box<dyn Error>> {
-    let matches = clap_app!(AdventOfCode2021 =>
-        (author: "Anthony Cicchetti")
-        (@setting ArgRequiredElseHelp)
-        (@arg day_to_execute: -d --day * +takes_value possible_values(&DaysImplemented::variants()))
-        (@arg part: -p --part * +takes_value possible_values(&["1", "2"]))
-        (@arg input_file: -f --file {file_exists} * conflicts_with[input_string] +takes_value "Input file")
-        (@arg input_string: required_unless[input_file] "Input string")
-    ).get_matches();
-    let day: DaysImplemented =
-        value_t!(matches.value_of("day_to_execute"), DaysImplemented).unwrap(); // Safe unwrap because value is required
-    let part = value_t!(matches.value_of("part"), u8).unwrap();
-    let input = match matches.value_of("input_file") {
-        None => value_t!(matches.value_of("input_string"), String).unwrap(),
+    let matches = App::new("AdventOfCode2021")
+        .author("Anthony Cicchetti")
+        .setting(ArgRequiredElseHelp)
+        .arg(
+            Arg::new("day_to_execute")
+                .short('d')
+                .long("day")
+                .takes_value(true)
+                .possible_values(vec!["Day1", "Day2"])
+                .about("Which day should be executed?"),
+        )
+        .arg(
+            Arg::new("part")
+                .short('p')
+                .long("part")
+                .takes_value(true)
+                .possible_values(vec!["1", "2"])
+                .about("Which part to execute?"),
+        )
+        .arg(
+            Arg::new("input_file")
+                .short('f')
+                .long("file")
+                .takes_value(true)
+                .validator(file_exists)
+                .conflicts_with("input_string")
+                .about("Input File"),
+        )
+        .arg(
+            Arg::new("input_string")
+                .required_unless_present("input_file")
+                .about("Input string"),
+        )
+        .get_matches();
+    let day: DaysImplemented = matches.value_of_t("day_to_execute").unwrap(); // Safe unwrap because value is required
+    let part: usize = matches.value_of_t("part").unwrap(); // Same as above
+    let input: String = match matches.value_of("input_file") {
+        None => matches.value_of_t("input_string").unwrap(),
         Some(path) => {
             let mut s = String::new();
             let _ = BufReader::new(File::open(path)?).read_to_string(&mut s);
@@ -48,7 +97,7 @@ fn main() -> Result<(), Box<dyn Error>> {
     Ok(())
 }
 
-fn file_exists(val: String) -> Result<(), String> {
+fn file_exists(val: &str) -> Result<(), String> {
     if std::fs::metadata(&val).is_ok() {
         Ok(())
     } else {