catでのエラー管理。

src/cat.zig

@@ -87,12 +87,18 @@ pub fn main() !void {
         }
     } else {
         for (fname.items) |item| {
-            const file = try fs.cwd().openFile(item, .{});
-            defer file.close();
+            const file = fs.cwd().openFile(item, .{});
+            if (file) |f| {
+                defer f.close();
+                const stat = try f.stat();
+                if (stat.kind == .directory) {
+                    std.debug.print("'{s}' はディレクトリです。\n", .{item});
+                    continue;
+                }
 
                 var buf: [1024]u8 = undefined;
                 while (true) {
-                const result = try file.reader().readUntilDelimiterOrEof(buf[0..], '\n') orelse break;
+                    const result = try f.reader().readUntilDelimiterOrEof(buf[0..], '\n') orelse break;
                     if (issqz and std.mem.trimRight(u8, result, "\n\r").len == 0) continue;
                     const stripped = std.mem.trim(u8, result, " \n\t\r");
 
@@ -111,6 +117,22 @@ pub fn main() !void {
                         try io.getStdOut().writer().print("\n", .{});
                     }
                 }
+            } else |err| {
+                switch (err) {
+                    error.FileNotFound => {
+                        std.debug.print("ファイルを見つけられません。\n", .{});
+                        break;
+                    },
+                    error.AccessDenied => {
+                        std.debug.print("アクセスに出来ません。\n", .{});
+                        break;
+                    },
+                    else => {
+                        std.debug.print("エラー。\n", .{});
+                        break;
+                    },
+                }
+            }
         }
     }
 }