Nomad changes

docs/snippets/zig/plugins/stateful_plugin.md

@@ -0,0 +1,67 @@
+```zig title="Zig"
+const std = @import("std");
+const kreuzberg = @import("kreuzberg");
+
+const StatefulProcessor = struct {
+    call_count: std.atomic.Value(usize) = std.atomic.Value(usize).init(0),
+
+    pub fn process(self: *StatefulProcessor, result: [*c]const u8, config: [*c]const u8) !void {
+        _ = result;
+        _ = config;
+        _ = self.call_count.fetchAdd(1, .acq_rel);
+    }
+
+    pub fn processing_stage(self: *StatefulProcessor) [*c]const u8 {
+        _ = self;
+        return "Middle";
+    }
+
+    pub fn should_process(self: *StatefulProcessor, result: [*c]const u8, config: [*c]const u8) i32 {
+        _ = self;
+        _ = result;
+        _ = config;
+        return 1;
+    }
+
+    pub fn estimated_duration_ms(self: *StatefulProcessor, result: [*c]const u8) u64 {
+        _ = self;
+        _ = result;
+        return 1;
+    }
+
+    pub fn priority(self: *StatefulProcessor) i32 {
+        _ = self;
+        return 50;
+    }
+};
+
+pub fn main() !void {
+    var instance = StatefulProcessor{};
+    var vtable = kreuzberg.make_post_processor_vtable(StatefulProcessor, &instance);
+
+    vtable.name_fn = struct {
+        fn thunk(user_data: ?*anyopaque, out_name: ?*?[*c]u8) callconv(.C) void {
+            _ = user_data;
+            if (out_name) |ptr| ptr.* = @constCast("stateful-processor");
+        }
+    }.thunk;
+    vtable.version_fn = struct {
+        fn thunk(user_data: ?*anyopaque, out_version: ?*?[*c]u8) callconv(.C) void {
+            _ = user_data;
+            if (out_version) |ptr| ptr.* = @constCast("1.0.0");
+        }
+    }.thunk;
+    vtable.shutdown_fn = struct {
+        fn thunk(user_data: ?*anyopaque, out_error: ?*?[*c]u8) callconv(.C) i32 {
+            _ = out_error;
+            const self: *StatefulProcessor = @ptrCast(@alignCast(user_data));
+            const count = self.call_count.load(.acquire);
+            std.log.info("stateful-processor invoked {d} times", .{count});
+            return 0;
+        }
+    }.thunk;
+
+    var out_error: ?[*c]u8 = null;
+    _ = kreuzberg.register_post_processor("stateful-processor", vtable, &instance, &out_error);
+}
+```