✨ Add bind-style context helpers

bitlogger/BitLogger_test.mbt

@@ -14,6 +14,15 @@ test "context sink merges fields" {
   logger.info("hello", fields=[field("mode", "test")])
 }
 
+test "fields helper builds field arrays ergonomically" {
+  let items = fields([("service", "bitlogger"), ("mode", "test")])
+  inspect(items.length(), content="2")
+  inspect(items[0].key, content="service")
+  inspect(items[0].value, content="bitlogger")
+  inspect(items[1].key, content="mode")
+  inspect(items[1].value, content="test")
+}
+
 test "fanout sink can write to plain and json outputs" {
   let logger = Logger::new(
     fanout_sink(console_sink(), json_console_sink()),

bitlogger/BitLogger_wbtest.mbt

@@ -259,6 +259,31 @@ test "callback sink sees child target and context logger shape" {
   inspect(captured_timestamp.val > 0UL, content="true")
 }
 
+test "bind aliases context fields ergonomically" {
+  let captured_target : Ref[String] = Ref::new("")
+  let captured_message : Ref[String] = Ref::new("")
+  let captured_fields : Ref[Array[Field]] = Ref::new([])
+  let logger = Logger::new(
+    callback_sink(fn(rec) {
+      captured_target.val = rec.target
+      captured_message.val = rec.message
+      captured_fields.val = rec.fields
+    }),
+    min_level=Level::Info,
+    target="bind",
+  ).bind(fields([("service", "bitlogger"), ("scope", "audit")]))
+  logger.info("ready", fields=[field("mode", "test")])
+  inspect(captured_target.val, content="bind")
+  inspect(captured_message.val, content="ready")
+  inspect(captured_fields.val.length(), content="3")
+  inspect(captured_fields.val[0].key, content="service")
+  inspect(captured_fields.val[0].value, content="bitlogger")
+  inspect(captured_fields.val[1].key, content="scope")
+  inspect(captured_fields.val[1].value, content="audit")
+  inspect(captured_fields.val[2].key, content="mode")
+  inspect(captured_fields.val[2].value, content="test")
+}
+
 test "buffered sink flushes manually" {
   let flushed_messages : Ref[Array[String]] = Ref::new([])
   let sink = buffered_sink(

bitlogger/README.mbt.md

@@ -36,6 +36,8 @@ BitLogger 是一个基于 MoonBit 的结构化日志库。
 - 提供 `target_has_prefix(...)`、`message_contains(...)`、`field_equals(...)` 等可复用过滤辅助函数
 - record patching via `with_patch(...)` and `patch_sink(...)`
 - 支持 `with_patch(...)`、`patch_sink(...)` 以及常见 record patch helper
+- context binding via `bind(...)` and `fields(...)`
+- 支持 `bind(...)`、`fields(...)`，更顺手地封装上下文字段
 - explicit queued delivery via `queued_sink(...)` and `with_queue(...)`
 - 支持 `queued_sink(...)`、`with_queue(...)`、有界积压与溢出策略
 - configurable text formatting via `text_formatter(...)`, `format_text(...)`, `text_console_sink(...)`, and template-driven `template` output
@@ -133,6 +135,14 @@ test {
 }
 ```
 
+```mbt check
+test {
+  let logger = Logger::new(console_sink(), target="audit")
+    .bind(fields([("service", "bitlogger"), ("scope", "login")]))
+  logger.info("accepted", fields=[field("user", "alice")])
+}
+```
+
 ```mbt check
 test {
   let logger = Logger::new(console_sink(), target="queue")

bitlogger/logger.mbt

@@ -36,6 +36,10 @@ pub fn[S] Logger::with_context_fields(self : Logger[S], fields : Array[Field]) -
   }
 }
 
+pub fn[S] Logger::bind(self : Logger[S], fields : Array[Field]) -> Logger[ContextSink[S]] {
+  self.with_context_fields(fields)
+}
+
 pub fn[S] Logger::with_filter(self : Logger[S], predicate : (Record) -> Bool) -> Logger[FilterSink[S]] {
   {
     min_level: self.min_level,

bitlogger/record.mbt

@@ -7,6 +7,12 @@ pub fn field(key : String, value : String) -> Field {
   { key, value }
 }
 
+pub fn fields(entries : Array[(String, String)]) -> Array[Field] {
+  entries.map(fn(entry) {
+    field(entry.0, entry.1)
+  })
+}
+
 pub struct Record {
   level : Level
   timestamp_ms : UInt64