init

src/executor.rs

@@ -0,0 +1,80 @@
+use std::env;
+use std::path::PathBuf;
+use std::process::Command;
+
+/// Execute a shell command line and print output directly to stdout/stderr.
+/// Returns the exit code.
+pub fn execute(input: &str) -> i32 {
+    let trimmed = input.trim();
+
+    // Handle cd specially - it must affect our process
+    if trimmed == "cd" || trimmed.starts_with("cd ") {
+        return handle_cd(trimmed);
+    }
+
+    // Run everything else through sh -c for full shell semantics
+    // (pipes, redirects, globs, etc.)
+    let status = Command::new("sh")
+        .arg("-c")
+        .arg(trimmed)
+        .status();
+
+    match status {
+        Ok(s) => s.code().unwrap_or(1),
+        Err(e) => {
+            eprintln!("aishell: {}", e);
+            127
+        }
+    }
+}
+
+fn handle_cd(input: &str) -> i32 {
+    let target = input.strip_prefix("cd").unwrap().trim();
+
+    let dir: PathBuf = if target.is_empty() {
+        // cd with no args → home directory
+        match env::var("HOME") {
+            Ok(home) => PathBuf::from(home),
+            Err(_) => {
+                eprintln!("aishell: cd: HOME not set");
+                return 1;
+            }
+        }
+    } else if target.starts_with('~') {
+        // Expand ~ to HOME
+        match env::var("HOME") {
+            Ok(home) => PathBuf::from(target.replacen('~', &home, 1)),
+            Err(_) => {
+                eprintln!("aishell: cd: HOME not set");
+                return 1;
+            }
+        }
+    } else if target == "-" {
+        // cd - → previous directory
+        match env::var("OLDPWD") {
+            Ok(old) => {
+                println!("{}", old);
+                PathBuf::from(old)
+            }
+            Err(_) => {
+                eprintln!("aishell: cd: OLDPWD not set");
+                return 1;
+            }
+        }
+    } else {
+        PathBuf::from(target)
+    };
+
+    // Save current dir as OLDPWD
+    if let Ok(cwd) = env::current_dir() {
+        env::set_var("OLDPWD", cwd);
+    }
+
+    match env::set_current_dir(&dir) {
+        Ok(_) => 0,
+        Err(e) => {
+            eprintln!("aishell: cd: {}: {}", dir.display(), e);
+            1
+        }
+    }
+}