Expand pwd command

Expand functionality of the pwd command to better handle the different
types of shells (e.g. FilesystemShell, ValueShell, etc.).

src/shell/filesystem_shell.rs

@@ -946,6 +946,28 @@ impl Shell for FilesystemShell {
         self.path.clone()
     }
 
+    fn pwd(&self, args: EvaluatedWholeStreamCommandArgs) -> Result<OutputStream, ShellError> {
+        let path = PathBuf::from(self.path());
+        let p = match dunce::canonicalize(path.as_path()) {
+            Ok(p) => p,
+            Err(_) => {
+                return Err(ShellError::labeled_error(
+                    "unable to show current directory",
+                    "pwd command failed",
+                    args.call_info.name_span,
+                ));
+            }
+        };
+
+        let mut stream = VecDeque::new();
+        stream.push_back(ReturnSuccess::value(
+            Value::Primitive(Primitive::String(p.to_string_lossy().to_string()))
+                .simple_spanned(args.call_info.name_span),
+        ));
+
+        Ok(stream.into())
+    }
+
     fn set_path(&mut self, path: String) {
         let pathbuf = PathBuf::from(&path);
         let path = match dunce::canonicalize(pathbuf.as_path()) {

src/shell/help_shell.rs

@@ -117,6 +117,10 @@ impl Shell for HelpShell {
         self.path.clone()
     }
 
+    fn pwd(&self, _: EvaluatedWholeStreamCommandArgs) -> Result<OutputStream, ShellError> {
+        Ok(OutputStream::empty())
+    }
+
     fn set_path(&mut self, path: String) {
         let _ = std::env::set_current_dir(&path);
         self.path = path.clone();

src/shell/shell.rs

@@ -20,6 +20,7 @@ pub trait Shell: std::fmt::Debug {
     fn mv(&self, args: MoveArgs, name: Span, path: &str) -> Result<OutputStream, ShellError>;
     fn rm(&self, args: RemoveArgs, name: Span, path: &str) -> Result<OutputStream, ShellError>;
     fn path(&self) -> String;
+    fn pwd(&self, args: EvaluatedWholeStreamCommandArgs) -> Result<OutputStream, ShellError>;
     fn set_path(&mut self, path: String);
 
     fn complete(

src/shell/shell_manager.rs

@@ -62,6 +62,12 @@ impl ShellManager {
         self.shells.lock().unwrap()[self.current_shell].path()
     }
 
+    pub fn pwd(&self, args: EvaluatedWholeStreamCommandArgs) -> Result<OutputStream, ShellError> {
+        let env = self.shells.lock().unwrap();
+
+        env[self.current_shell].pwd(args)
+    }
+
     pub fn set_path(&mut self, path: String) {
         self.shells.lock().unwrap()[self.current_shell].set_path(path)
     }

src/shell/value_shell.rs

@@ -199,6 +199,18 @@ impl Shell for ValueShell {
         self.path.clone()
     }
 
+    fn pwd(&self, args: EvaluatedWholeStreamCommandArgs) -> Result<OutputStream, ShellError> {
+        let path = PathBuf::from(&self.path());
+
+        let mut stream = VecDeque::new();
+        stream.push_back(ReturnSuccess::value(
+            Value::Primitive(Primitive::String(path.to_string_lossy().to_string()))
+                .simple_spanned(args.call_info.name_span),
+        ));
+
+        Ok(stream.into())
+    }
+
     fn set_path(&mut self, path: String) {
         let _ = std::env::set_current_dir(&path);
         self.path = path.clone();