Checking against user input and returns a response based on that input












1












$begingroup$


How could I use enums in the following block of code to simplify it? The block is a program that has a command interpreter that returns different data based on user input. Is there a way I could easily apply enums and a match statement to the logic here?



use std::io;

fn main() {
let version = String::from("0.0.1");
let mut input = String::new();

shell(&mut input, &version);
}

fn shell(input: &mut String, version: &String) {
input.clear();
match io::stdin().read_line(input) {
Ok(b) => {
if &input.trim() == &"ver" || &input.trim() == &"what are you" {
println!("C ute R ust A mateur B eginner Shell ver: {}", version);
shell(input, version);
} else {
println!("Command '{}' Not Recognized", input);
shell(input, &version);
}
}
Err(err) => panic!("incorrect"),
}
}









share|improve this question









New contributor




rustacean_in_training is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.







$endgroup$

















    1












    $begingroup$


    How could I use enums in the following block of code to simplify it? The block is a program that has a command interpreter that returns different data based on user input. Is there a way I could easily apply enums and a match statement to the logic here?



    use std::io;

    fn main() {
    let version = String::from("0.0.1");
    let mut input = String::new();

    shell(&mut input, &version);
    }

    fn shell(input: &mut String, version: &String) {
    input.clear();
    match io::stdin().read_line(input) {
    Ok(b) => {
    if &input.trim() == &"ver" || &input.trim() == &"what are you" {
    println!("C ute R ust A mateur B eginner Shell ver: {}", version);
    shell(input, version);
    } else {
    println!("Command '{}' Not Recognized", input);
    shell(input, &version);
    }
    }
    Err(err) => panic!("incorrect"),
    }
    }









    share|improve this question









    New contributor




    rustacean_in_training is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
    Check out our Code of Conduct.







    $endgroup$















      1












      1








      1





      $begingroup$


      How could I use enums in the following block of code to simplify it? The block is a program that has a command interpreter that returns different data based on user input. Is there a way I could easily apply enums and a match statement to the logic here?



      use std::io;

      fn main() {
      let version = String::from("0.0.1");
      let mut input = String::new();

      shell(&mut input, &version);
      }

      fn shell(input: &mut String, version: &String) {
      input.clear();
      match io::stdin().read_line(input) {
      Ok(b) => {
      if &input.trim() == &"ver" || &input.trim() == &"what are you" {
      println!("C ute R ust A mateur B eginner Shell ver: {}", version);
      shell(input, version);
      } else {
      println!("Command '{}' Not Recognized", input);
      shell(input, &version);
      }
      }
      Err(err) => panic!("incorrect"),
      }
      }









      share|improve this question









      New contributor




      rustacean_in_training is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
      Check out our Code of Conduct.







      $endgroup$




      How could I use enums in the following block of code to simplify it? The block is a program that has a command interpreter that returns different data based on user input. Is there a way I could easily apply enums and a match statement to the logic here?



      use std::io;

      fn main() {
      let version = String::from("0.0.1");
      let mut input = String::new();

      shell(&mut input, &version);
      }

      fn shell(input: &mut String, version: &String) {
      input.clear();
      match io::stdin().read_line(input) {
      Ok(b) => {
      if &input.trim() == &"ver" || &input.trim() == &"what are you" {
      println!("C ute R ust A mateur B eginner Shell ver: {}", version);
      shell(input, version);
      } else {
      println!("Command '{}' Not Recognized", input);
      shell(input, &version);
      }
      }
      Err(err) => panic!("incorrect"),
      }
      }






      rust






      share|improve this question









      New contributor




      rustacean_in_training is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
      Check out our Code of Conduct.











      share|improve this question









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      share|improve this question




      share|improve this question








      edited 3 mins ago









      Jamal

      30.3k11119227




      30.3k11119227






      New contributor




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      asked 4 hours ago









      rustacean_in_trainingrustacean_in_training

      61




      61




      New contributor




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      New contributor





      rustacean_in_training is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
      Check out our Code of Conduct.






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      Check out our Code of Conduct.






















          1 Answer
          1






          active

          oldest

          votes


















          0












          $begingroup$


          1. Use rustfmt. I know the code you've presented is formatted correctly now, but that's because I reformatted it for you over on Stack Overflow (I wouldn't have touched it here).



          2. Read and address the compiler's warning messages!



            warning: unused variable: `b`
            --> src/main.rs:13:12
            |
            13 | Ok(b) => {
            | ^ help: consider using `_b` instead
            |
            = note: #[warn(unused_variables)] on by default

            warning: unused variable: `err`
            --> src/main.rs:22:13
            |
            22 | Err(err) => panic!("incorrect"),
            | ^^^ help: consider using `_err` instead

            warning: function cannot return without recursing
            --> src/main.rs:10:1
            |
            10 | fn shell(input: &mut String, version: &String) {
            | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot return without recursing
            ...
            16 | shell(input, version);
            | --------------------- recursive call site
            ...
            19 | shell(input, &version);
            | ---------------------- recursive call site
            |
            = note: #[warn(unconditional_recursion)] on by default
            = help: a `loop` may express intention better if this is on purpose

            Finished dev [unoptimized + debuginfo] target(s) in 2.16s
            Running `target/debug/playground`


          3. Don't have infinite recursion; that's almost always a bad idea and you will run out of stack space. Write an infinite loop instead.


          4. There's no reason to put input outside of the function, as it's only ever used inside it.



          5. Use clippy. It will point out things like:



            warning: writing `&String` instead of `&str` involves a new object where a slice will do.
            --> src/main.rs:9:19
            |
            9 | fn shell(version: &String) {
            | ^^^^^^^ help: change this to: `&str`
            |
            = note: #[warn(clippy::ptr_arg)] on by default
            = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#ptr_arg

            warning: needlessly taken reference of both operands
            --> src/main.rs:15:16
            |
            15 | if &input.trim() == &"ver" || &input.trim() == &"what are you" {
            | ^^^^^^^^^^^^^^^^^^^^^^^
            |
            = note: #[warn(clippy::op_ref)] on by default
            = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#op_ref
            help: use the values directly
            |
            15 | if input.trim() == "ver" || &input.trim() == &"what are you" {
            | ^^^^^^^^^^^^ ^^^^^


            See also:




            • Why is it discouraged to accept a reference to a String (&String), Vec (&Vec), or Box (&Box) as a function argument?



          6. Use Result::expect instead of doing the match yourself. This has the beenfit of printing out the underlying error message as well.


          7. Store the result of trim to avoid doing the work multiple times.


          8. Consider using a match on the trimmed string to decide what to work on.



          use std::io;

          fn main() {
          let version = "0.0.1";

          shell(version);
          }

          fn shell(version: &str) {
          let mut input = String::new();
          loop {
          input.clear();
          io::stdin().read_line(&mut input).expect("incorrect");
          let input = input.trim();

          match input {
          "ver" | "what are you" => {
          println!("C ute R ust A mateur B eginner Shell ver: {}", version)
          }
          _ => println!("Command '{}' Not Recognized", input),
          }
          }
          }


          Now we can consider how best to use enums here. An enum is good for a type that can be one of many values. You have that structure in your "command" decisions. You could create an enum from those strings:



          use std::io;

          fn main() {
          let version = "0.0.1";

          shell(version);
          }

          fn shell(version: &str) {
          let mut input = String::new();
          loop {
          input.clear();
          io::stdin().read_line(&mut input).expect("incorrect");
          let command = input.trim().parse::<Command>();

          use Command::*;
          match command {
          Ok(Version) | Ok(WhatAreYou) => {
          println!("C ute R ust A mateur B eginner Shell ver: {}", version)
          }
          Err(_) => println!("Command '{}' Not Recognized", input),
          }
          }
          }

          #[derive(Debug)]
          enum Command {
          Version,
          WhatAreYou,
          }

          impl std::str::FromStr for Command {
          type Err = ();

          fn from_str(input: &str) -> Result<Self, Self::Err> {
          use Command::*;
          Ok(match input {
          "ver" => Version,
          "what are you" => WhatAreYou,
          _ => return Err(()),
          })
          }
          }
          ```





          share|improve this answer









          $endgroup$













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            0












            $begingroup$


            1. Use rustfmt. I know the code you've presented is formatted correctly now, but that's because I reformatted it for you over on Stack Overflow (I wouldn't have touched it here).



            2. Read and address the compiler's warning messages!



              warning: unused variable: `b`
              --> src/main.rs:13:12
              |
              13 | Ok(b) => {
              | ^ help: consider using `_b` instead
              |
              = note: #[warn(unused_variables)] on by default

              warning: unused variable: `err`
              --> src/main.rs:22:13
              |
              22 | Err(err) => panic!("incorrect"),
              | ^^^ help: consider using `_err` instead

              warning: function cannot return without recursing
              --> src/main.rs:10:1
              |
              10 | fn shell(input: &mut String, version: &String) {
              | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot return without recursing
              ...
              16 | shell(input, version);
              | --------------------- recursive call site
              ...
              19 | shell(input, &version);
              | ---------------------- recursive call site
              |
              = note: #[warn(unconditional_recursion)] on by default
              = help: a `loop` may express intention better if this is on purpose

              Finished dev [unoptimized + debuginfo] target(s) in 2.16s
              Running `target/debug/playground`


            3. Don't have infinite recursion; that's almost always a bad idea and you will run out of stack space. Write an infinite loop instead.


            4. There's no reason to put input outside of the function, as it's only ever used inside it.



            5. Use clippy. It will point out things like:



              warning: writing `&String` instead of `&str` involves a new object where a slice will do.
              --> src/main.rs:9:19
              |
              9 | fn shell(version: &String) {
              | ^^^^^^^ help: change this to: `&str`
              |
              = note: #[warn(clippy::ptr_arg)] on by default
              = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#ptr_arg

              warning: needlessly taken reference of both operands
              --> src/main.rs:15:16
              |
              15 | if &input.trim() == &"ver" || &input.trim() == &"what are you" {
              | ^^^^^^^^^^^^^^^^^^^^^^^
              |
              = note: #[warn(clippy::op_ref)] on by default
              = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#op_ref
              help: use the values directly
              |
              15 | if input.trim() == "ver" || &input.trim() == &"what are you" {
              | ^^^^^^^^^^^^ ^^^^^


              See also:




              • Why is it discouraged to accept a reference to a String (&String), Vec (&Vec), or Box (&Box) as a function argument?



            6. Use Result::expect instead of doing the match yourself. This has the beenfit of printing out the underlying error message as well.


            7. Store the result of trim to avoid doing the work multiple times.


            8. Consider using a match on the trimmed string to decide what to work on.



            use std::io;

            fn main() {
            let version = "0.0.1";

            shell(version);
            }

            fn shell(version: &str) {
            let mut input = String::new();
            loop {
            input.clear();
            io::stdin().read_line(&mut input).expect("incorrect");
            let input = input.trim();

            match input {
            "ver" | "what are you" => {
            println!("C ute R ust A mateur B eginner Shell ver: {}", version)
            }
            _ => println!("Command '{}' Not Recognized", input),
            }
            }
            }


            Now we can consider how best to use enums here. An enum is good for a type that can be one of many values. You have that structure in your "command" decisions. You could create an enum from those strings:



            use std::io;

            fn main() {
            let version = "0.0.1";

            shell(version);
            }

            fn shell(version: &str) {
            let mut input = String::new();
            loop {
            input.clear();
            io::stdin().read_line(&mut input).expect("incorrect");
            let command = input.trim().parse::<Command>();

            use Command::*;
            match command {
            Ok(Version) | Ok(WhatAreYou) => {
            println!("C ute R ust A mateur B eginner Shell ver: {}", version)
            }
            Err(_) => println!("Command '{}' Not Recognized", input),
            }
            }
            }

            #[derive(Debug)]
            enum Command {
            Version,
            WhatAreYou,
            }

            impl std::str::FromStr for Command {
            type Err = ();

            fn from_str(input: &str) -> Result<Self, Self::Err> {
            use Command::*;
            Ok(match input {
            "ver" => Version,
            "what are you" => WhatAreYou,
            _ => return Err(()),
            })
            }
            }
            ```





            share|improve this answer









            $endgroup$


















              0












              $begingroup$


              1. Use rustfmt. I know the code you've presented is formatted correctly now, but that's because I reformatted it for you over on Stack Overflow (I wouldn't have touched it here).



              2. Read and address the compiler's warning messages!



                warning: unused variable: `b`
                --> src/main.rs:13:12
                |
                13 | Ok(b) => {
                | ^ help: consider using `_b` instead
                |
                = note: #[warn(unused_variables)] on by default

                warning: unused variable: `err`
                --> src/main.rs:22:13
                |
                22 | Err(err) => panic!("incorrect"),
                | ^^^ help: consider using `_err` instead

                warning: function cannot return without recursing
                --> src/main.rs:10:1
                |
                10 | fn shell(input: &mut String, version: &String) {
                | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot return without recursing
                ...
                16 | shell(input, version);
                | --------------------- recursive call site
                ...
                19 | shell(input, &version);
                | ---------------------- recursive call site
                |
                = note: #[warn(unconditional_recursion)] on by default
                = help: a `loop` may express intention better if this is on purpose

                Finished dev [unoptimized + debuginfo] target(s) in 2.16s
                Running `target/debug/playground`


              3. Don't have infinite recursion; that's almost always a bad idea and you will run out of stack space. Write an infinite loop instead.


              4. There's no reason to put input outside of the function, as it's only ever used inside it.



              5. Use clippy. It will point out things like:



                warning: writing `&String` instead of `&str` involves a new object where a slice will do.
                --> src/main.rs:9:19
                |
                9 | fn shell(version: &String) {
                | ^^^^^^^ help: change this to: `&str`
                |
                = note: #[warn(clippy::ptr_arg)] on by default
                = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#ptr_arg

                warning: needlessly taken reference of both operands
                --> src/main.rs:15:16
                |
                15 | if &input.trim() == &"ver" || &input.trim() == &"what are you" {
                | ^^^^^^^^^^^^^^^^^^^^^^^
                |
                = note: #[warn(clippy::op_ref)] on by default
                = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#op_ref
                help: use the values directly
                |
                15 | if input.trim() == "ver" || &input.trim() == &"what are you" {
                | ^^^^^^^^^^^^ ^^^^^


                See also:




                • Why is it discouraged to accept a reference to a String (&String), Vec (&Vec), or Box (&Box) as a function argument?



              6. Use Result::expect instead of doing the match yourself. This has the beenfit of printing out the underlying error message as well.


              7. Store the result of trim to avoid doing the work multiple times.


              8. Consider using a match on the trimmed string to decide what to work on.



              use std::io;

              fn main() {
              let version = "0.0.1";

              shell(version);
              }

              fn shell(version: &str) {
              let mut input = String::new();
              loop {
              input.clear();
              io::stdin().read_line(&mut input).expect("incorrect");
              let input = input.trim();

              match input {
              "ver" | "what are you" => {
              println!("C ute R ust A mateur B eginner Shell ver: {}", version)
              }
              _ => println!("Command '{}' Not Recognized", input),
              }
              }
              }


              Now we can consider how best to use enums here. An enum is good for a type that can be one of many values. You have that structure in your "command" decisions. You could create an enum from those strings:



              use std::io;

              fn main() {
              let version = "0.0.1";

              shell(version);
              }

              fn shell(version: &str) {
              let mut input = String::new();
              loop {
              input.clear();
              io::stdin().read_line(&mut input).expect("incorrect");
              let command = input.trim().parse::<Command>();

              use Command::*;
              match command {
              Ok(Version) | Ok(WhatAreYou) => {
              println!("C ute R ust A mateur B eginner Shell ver: {}", version)
              }
              Err(_) => println!("Command '{}' Not Recognized", input),
              }
              }
              }

              #[derive(Debug)]
              enum Command {
              Version,
              WhatAreYou,
              }

              impl std::str::FromStr for Command {
              type Err = ();

              fn from_str(input: &str) -> Result<Self, Self::Err> {
              use Command::*;
              Ok(match input {
              "ver" => Version,
              "what are you" => WhatAreYou,
              _ => return Err(()),
              })
              }
              }
              ```





              share|improve this answer









              $endgroup$
















                0












                0








                0





                $begingroup$


                1. Use rustfmt. I know the code you've presented is formatted correctly now, but that's because I reformatted it for you over on Stack Overflow (I wouldn't have touched it here).



                2. Read and address the compiler's warning messages!



                  warning: unused variable: `b`
                  --> src/main.rs:13:12
                  |
                  13 | Ok(b) => {
                  | ^ help: consider using `_b` instead
                  |
                  = note: #[warn(unused_variables)] on by default

                  warning: unused variable: `err`
                  --> src/main.rs:22:13
                  |
                  22 | Err(err) => panic!("incorrect"),
                  | ^^^ help: consider using `_err` instead

                  warning: function cannot return without recursing
                  --> src/main.rs:10:1
                  |
                  10 | fn shell(input: &mut String, version: &String) {
                  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot return without recursing
                  ...
                  16 | shell(input, version);
                  | --------------------- recursive call site
                  ...
                  19 | shell(input, &version);
                  | ---------------------- recursive call site
                  |
                  = note: #[warn(unconditional_recursion)] on by default
                  = help: a `loop` may express intention better if this is on purpose

                  Finished dev [unoptimized + debuginfo] target(s) in 2.16s
                  Running `target/debug/playground`


                3. Don't have infinite recursion; that's almost always a bad idea and you will run out of stack space. Write an infinite loop instead.


                4. There's no reason to put input outside of the function, as it's only ever used inside it.



                5. Use clippy. It will point out things like:



                  warning: writing `&String` instead of `&str` involves a new object where a slice will do.
                  --> src/main.rs:9:19
                  |
                  9 | fn shell(version: &String) {
                  | ^^^^^^^ help: change this to: `&str`
                  |
                  = note: #[warn(clippy::ptr_arg)] on by default
                  = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#ptr_arg

                  warning: needlessly taken reference of both operands
                  --> src/main.rs:15:16
                  |
                  15 | if &input.trim() == &"ver" || &input.trim() == &"what are you" {
                  | ^^^^^^^^^^^^^^^^^^^^^^^
                  |
                  = note: #[warn(clippy::op_ref)] on by default
                  = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#op_ref
                  help: use the values directly
                  |
                  15 | if input.trim() == "ver" || &input.trim() == &"what are you" {
                  | ^^^^^^^^^^^^ ^^^^^


                  See also:




                  • Why is it discouraged to accept a reference to a String (&String), Vec (&Vec), or Box (&Box) as a function argument?



                6. Use Result::expect instead of doing the match yourself. This has the beenfit of printing out the underlying error message as well.


                7. Store the result of trim to avoid doing the work multiple times.


                8. Consider using a match on the trimmed string to decide what to work on.



                use std::io;

                fn main() {
                let version = "0.0.1";

                shell(version);
                }

                fn shell(version: &str) {
                let mut input = String::new();
                loop {
                input.clear();
                io::stdin().read_line(&mut input).expect("incorrect");
                let input = input.trim();

                match input {
                "ver" | "what are you" => {
                println!("C ute R ust A mateur B eginner Shell ver: {}", version)
                }
                _ => println!("Command '{}' Not Recognized", input),
                }
                }
                }


                Now we can consider how best to use enums here. An enum is good for a type that can be one of many values. You have that structure in your "command" decisions. You could create an enum from those strings:



                use std::io;

                fn main() {
                let version = "0.0.1";

                shell(version);
                }

                fn shell(version: &str) {
                let mut input = String::new();
                loop {
                input.clear();
                io::stdin().read_line(&mut input).expect("incorrect");
                let command = input.trim().parse::<Command>();

                use Command::*;
                match command {
                Ok(Version) | Ok(WhatAreYou) => {
                println!("C ute R ust A mateur B eginner Shell ver: {}", version)
                }
                Err(_) => println!("Command '{}' Not Recognized", input),
                }
                }
                }

                #[derive(Debug)]
                enum Command {
                Version,
                WhatAreYou,
                }

                impl std::str::FromStr for Command {
                type Err = ();

                fn from_str(input: &str) -> Result<Self, Self::Err> {
                use Command::*;
                Ok(match input {
                "ver" => Version,
                "what are you" => WhatAreYou,
                _ => return Err(()),
                })
                }
                }
                ```





                share|improve this answer









                $endgroup$




                1. Use rustfmt. I know the code you've presented is formatted correctly now, but that's because I reformatted it for you over on Stack Overflow (I wouldn't have touched it here).



                2. Read and address the compiler's warning messages!



                  warning: unused variable: `b`
                  --> src/main.rs:13:12
                  |
                  13 | Ok(b) => {
                  | ^ help: consider using `_b` instead
                  |
                  = note: #[warn(unused_variables)] on by default

                  warning: unused variable: `err`
                  --> src/main.rs:22:13
                  |
                  22 | Err(err) => panic!("incorrect"),
                  | ^^^ help: consider using `_err` instead

                  warning: function cannot return without recursing
                  --> src/main.rs:10:1
                  |
                  10 | fn shell(input: &mut String, version: &String) {
                  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot return without recursing
                  ...
                  16 | shell(input, version);
                  | --------------------- recursive call site
                  ...
                  19 | shell(input, &version);
                  | ---------------------- recursive call site
                  |
                  = note: #[warn(unconditional_recursion)] on by default
                  = help: a `loop` may express intention better if this is on purpose

                  Finished dev [unoptimized + debuginfo] target(s) in 2.16s
                  Running `target/debug/playground`


                3. Don't have infinite recursion; that's almost always a bad idea and you will run out of stack space. Write an infinite loop instead.


                4. There's no reason to put input outside of the function, as it's only ever used inside it.



                5. Use clippy. It will point out things like:



                  warning: writing `&String` instead of `&str` involves a new object where a slice will do.
                  --> src/main.rs:9:19
                  |
                  9 | fn shell(version: &String) {
                  | ^^^^^^^ help: change this to: `&str`
                  |
                  = note: #[warn(clippy::ptr_arg)] on by default
                  = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#ptr_arg

                  warning: needlessly taken reference of both operands
                  --> src/main.rs:15:16
                  |
                  15 | if &input.trim() == &"ver" || &input.trim() == &"what are you" {
                  | ^^^^^^^^^^^^^^^^^^^^^^^
                  |
                  = note: #[warn(clippy::op_ref)] on by default
                  = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#op_ref
                  help: use the values directly
                  |
                  15 | if input.trim() == "ver" || &input.trim() == &"what are you" {
                  | ^^^^^^^^^^^^ ^^^^^


                  See also:




                  • Why is it discouraged to accept a reference to a String (&String), Vec (&Vec), or Box (&Box) as a function argument?



                6. Use Result::expect instead of doing the match yourself. This has the beenfit of printing out the underlying error message as well.


                7. Store the result of trim to avoid doing the work multiple times.


                8. Consider using a match on the trimmed string to decide what to work on.



                use std::io;

                fn main() {
                let version = "0.0.1";

                shell(version);
                }

                fn shell(version: &str) {
                let mut input = String::new();
                loop {
                input.clear();
                io::stdin().read_line(&mut input).expect("incorrect");
                let input = input.trim();

                match input {
                "ver" | "what are you" => {
                println!("C ute R ust A mateur B eginner Shell ver: {}", version)
                }
                _ => println!("Command '{}' Not Recognized", input),
                }
                }
                }


                Now we can consider how best to use enums here. An enum is good for a type that can be one of many values. You have that structure in your "command" decisions. You could create an enum from those strings:



                use std::io;

                fn main() {
                let version = "0.0.1";

                shell(version);
                }

                fn shell(version: &str) {
                let mut input = String::new();
                loop {
                input.clear();
                io::stdin().read_line(&mut input).expect("incorrect");
                let command = input.trim().parse::<Command>();

                use Command::*;
                match command {
                Ok(Version) | Ok(WhatAreYou) => {
                println!("C ute R ust A mateur B eginner Shell ver: {}", version)
                }
                Err(_) => println!("Command '{}' Not Recognized", input),
                }
                }
                }

                #[derive(Debug)]
                enum Command {
                Version,
                WhatAreYou,
                }

                impl std::str::FromStr for Command {
                type Err = ();

                fn from_str(input: &str) -> Result<Self, Self::Err> {
                use Command::*;
                Ok(match input {
                "ver" => Version,
                "what are you" => WhatAreYou,
                _ => return Err(()),
                })
                }
                }
                ```






                share|improve this answer












                share|improve this answer



                share|improve this answer










                answered 57 mins ago









                ShepmasterShepmaster

                7,0831219




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