refactor: improve arg parsingHEADmain

2 files changed, 47 insertions, 52 deletions

diff --git a/src/cli.rs b/src/cli.rs
index 8c72155..968c33f 100644
--- a/src/cli.rs
+++ b/src/cli.rs
@@ -27,7 +27,14 @@ impl Cli {
     fn parse_arg(mut self, opt: String) -> Result<Self> {
         match opt.as_str() {
             "-" => self.files.push(Input::Stdin),
-            o if o.starts_with('-') => self.opts.parse_opt(o)?,
+            s if s.starts_with("--") => {
+                self.opts.try_set_opt(s)?;
+            }
+            s if s.starts_with('-') => {
+                s.chars()
+                    .skip(1)
+                    .try_fold(&mut self.opts, Opts::try_set_opt)?;
+            }
             s => self.files.push(s.into()),
         };
         Ok(self)
@@ -47,30 +54,14 @@ pub struct Opts {
 }
 
 impl Opts {
-    fn parse_opt(&mut self, s: &str) -> Result<()> {
-        if s.starts_with("--") {
-            self.parse_long(s)
-        } else if s.starts_with('-') {
-            self.parse_short(s)
-        } else {
-            Err(Error::Opts(format!("`{}` is not an option.", s)))
-        }
-    }
-
-    fn parse_short(&mut self, short: &str) -> Result<()> {
-        short
-            .trim_start_matches('-')
-            .chars()
-            .map(Into::into)
-            .try_for_each(|opt| self.set_opt(opt))
-    }
-
-    fn parse_long(&mut self, long: &str) -> Result<()> {
-        let opt = long.trim_start_matches('-').into();
-        self.set_opt(opt)
+    fn try_set_opt<T>(&mut self, t: T) -> Result<&mut Self>
+    where
+        T: TryInto<Opt, Error = Error>,
+    {
+        t.try_into().map(|opt| self.set_opt(opt))
     }
 
-    fn set_opt(&mut self, opt: Opt) -> Result<()> {
+    pub fn set_opt(&mut self, opt: Opt) -> &mut Self {
         match opt {
             Opt::ShowAll => {
                 self.show_ends = true;
@@ -94,14 +85,13 @@ impl Opts {
             Opt::ShowNonprinting => self.show_nonprinting = true,
             Opt::Help => self.help = true,
             Opt::Version => self.version = true,
-            Opt::Unknown(s) => return Err(Error::Opts(s)),
         };
-        Ok(())
+        self
     }
 }
 
 #[derive(Debug)]
-enum Opt {
+pub enum Opt {
     /// -A, --show-all
     ///
     /// equivalent to -vET
@@ -161,14 +151,13 @@ enum Opt {
     ///
     /// output version information and exit
     Version,
-
-    /// unrecognized option
-    Unknown(String),
 }
 
-impl From<char> for Opt {
-    fn from(value: char) -> Self {
-        match value {
+impl TryFrom<char> for Opt {
+    type Error = Error;
+
+    fn try_from(value: char) -> Result<Self> {
+        let opt = match value {
             'A' => Self::ShowAll,
             'b' => Self::NumberNonblank,
             'e' => Self::ShowEndsNonprinting,
@@ -179,24 +168,30 @@ impl From<char> for Opt {
             'T' => Self::ShowTabs,
             'u' => Self::Ignored,
             'v' => Self::ShowNonprinting,
-            s => Self::Unknown(s.into()),
-        }
+            s => return Err(Error::Opts(s.into())),
+        };
+
+        Ok(opt)
     }
 }
 
-impl From<&str> for Opt {
-    fn from(value: &str) -> Self {
-        match value {
-            "show-all" => Self::ShowAll,
-            "number-nonblank" => Self::NumberNonblank,
-            "show-ends" => Self::ShowEnds,
-            "number" => Self::Number,
-            "squeeze-blank" => Self::SqueezeBlank,
-            "show-tabs" => Self::ShowTabs,
-            "show-nonprinting" => Self::ShowNonprinting,
-            "help" => Self::Help,
-            "version" => Self::Version,
-            s => Self::Unknown(s.into()),
-        }
+impl TryFrom<&str> for Opt {
+    type Error = Error;
+
+    fn try_from(value: &str) -> Result<Self> {
+        let opt = match value {
+            "--show-all" => Self::ShowAll,
+            "--number-nonblank" => Self::NumberNonblank,
+            "--show-ends" => Self::ShowEnds,
+            "--number" => Self::Number,
+            "--squeeze-blank" => Self::SqueezeBlank,
+            "--show-tabs" => Self::ShowTabs,
+            "--show-nonprinting" => Self::ShowNonprinting,
+            "--help" => Self::Help,
+            "--version" => Self::Version,
+            s => return Err(Error::Opts(s.into())),
+        };
+
+        Ok(opt)
     }
 }
diff --git a/src/lib.rs b/src/lib.rs
index 92c8b3a..1d05eaf 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -103,6 +103,8 @@ fn process_nonprinting(mut c: u8) -> Vec<u8> {
 
 #[cfg(test)]
 mod test {
+    use crate::cli::Opt;
+
     use super::*;
 
     use std::process::{Command, Stdio};
@@ -132,10 +134,8 @@ mod test {
         let cat_output = cat_child.wait_with_output().unwrap();
         let cat_result = String::from_utf8(cat_output.stdout).unwrap();
 
-        let opts = Opts {
-            show_nonprinting: true,
-            ..Default::default()
-        };
+        let mut opts = Opts::default();
+        opts.set_opt(Opt::ShowNonprinting);
 
         let mut writer = Vec::new();