1 files changed, 42 insertions, 4 deletions

diff --git a/src/main.rs b/src/main.rs
index c912c04..328c4ba 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -36,15 +36,12 @@ macro_rules! println {
     }};
 }
 
-const PROMPT: &str = "> ";
-
 fn completely_clear_screen() {
     print!("\x1B[2J\x1B[1;1H");
 }
 
 fn clear_screen() {
     completely_clear_screen();
-    print!("{PROMPT}")
 }
 
 type BString = Vec<u8>;
@@ -58,6 +55,47 @@ pub struct Session {
     dispatch: CommandDispatch,
 }
 
+/// relative path -- in case it is a proper subpath the result starts with a slash `/`
+fn relative_path(root: &Path, target: &Path) -> Option<String> {
+    let root = root.to_string_lossy();
+    let mut target = target.to_string_lossy().to_string();
+    if !target.ends_with("/") {
+        target += "/";
+    }
+    if let Some(("", leaf)) = target.split_once(&*root) {
+        Some(leaf.into())
+    } else {
+        None
+    }
+}
+
+impl Session {
+    fn pretty_cwd_res(&self) -> io::Result<String> {
+        let dir = std::env::current_dir()?;
+        let mut s = if let Some(home_dir) = std::env::home_dir() {
+            if let Some(rela) = relative_path(&home_dir, &dir) {
+                format!("~{rela}")
+            } else {
+                dir.to_string_lossy().to_string()
+            }
+        } else {
+            dir.to_string_lossy().to_string()
+        };
+        while s.ends_with("/") {
+            s.remove(s.len() - 1);
+        }
+        Ok(s)
+    }
+
+    fn pretty_cwd(&self) -> String {
+        self.pretty_cwd_res().unwrap_or_else(|_| String::new())
+    }
+
+    fn prompt(&self) -> String {
+        format!("{} $ ", self.pretty_cwd())
+    }
+}
+
 fn event_loop() {
     let stdin = io::stdin();
     let stdout = io::stdout();
@@ -73,7 +111,7 @@ fn event_loop() {
         dispatch: CommandDispatch::new(),
     };
 
-    print!("{PROMPT}");
+    print!("{}", se.prompt());
 
     loop {
         let mut buf = [0u8; 1];