codecrafters submit [skip ci]

1 files changed, 35 insertions, 3 deletions

diff --git a/src/main.zig b/src/main.zig
index 92067a4..10c5c1d 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -36,7 +36,33 @@ fn isBuiltin(cmd_name: []const u8) bool {
     return false;
 }
 
-fn executeCommand(cmd_name: []const u8, args: ?[]const u8) !CommandResult {
+fn findInPath(allocator: std.mem.Allocator, cmd_name: []const u8) !?[]const u8 {
+    const path_env = std.process.getEnvVarOwned(allocator, "PATH") catch return null;
+    defer allocator.free(path_env);
+
+    var it = std.mem.splitScalar(u8, path_env, ':');
+    while (it.next()) |dir| {
+        const full_path = std.fs.path.join(allocator, &[_][]const u8{ dir, cmd_name }) catch continue;
+        defer allocator.free(full_path);
+
+        const file = std.fs.openFileAbsolute(full_path, .{}) catch continue;
+        const stat = file.stat() catch {
+            file.close();
+            continue;
+        };
+        file.close();
+
+        const mode = stat.mode;
+        const has_exec = (mode & 0o111) != 0;
+        if (!has_exec) continue;
+
+        return try allocator.dupe(u8, full_path);
+    }
+
+    return null;
+}
+
+fn executeCommand(allocator: std.mem.Allocator, cmd_name: []const u8, args: ?[]const u8) !CommandResult {
     if (std.mem.eql(u8, cmd_name, "exit")) {
         return .exit_shell;
     }
@@ -54,6 +80,9 @@ fn executeCommand(cmd_name: []const u8, args: ?[]const u8) !CommandResult {
         if (args) |a| {
             if (isBuiltin(a)) {
                 try stdout.print("{s} is a shell builtin\n", .{a});
+            } else if (try findInPath(allocator, a)) |path| {
+                defer allocator.free(path);
+                try stdout.print("{s} is {s}\n", .{ a, path });
             } else {
                 try stdout.print("{s}: not found\n", .{a});
             }
@@ -61,19 +90,22 @@ fn executeCommand(cmd_name: []const u8, args: ?[]const u8) !CommandResult {
         return .continue_loop;
     }
 
-    // Command not found
     try stdout.print("{s}: command not found\n", .{cmd_name});
     return .continue_loop;
 }
 
 pub fn main() !void {
+    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
+    defer _ = gpa.deinit();
+    const allocator = gpa.allocator();
+
     while (true) {
         try stdout.print("$ ", .{});
 
         const command = try stdin.takeDelimiter('\n');
         if (command) |cmd| {
             const parsed = parseCommand(cmd);
-            const result = try executeCommand(parsed.name, parsed.args);
+            const result = try executeCommand(allocator, parsed.name, parsed.args);
 
             if (result == .exit_shell) {
                 break;