Logger-bind

Attach shared structured fields to a logger through the bind(...) alias. This API is behaviorally identical to with_context_fields(...) and exists as a shorter name for common structured context binding.

Interface

pub fn[S] Logger::bind(self : Logger[S], fields : Array[Field]) -> Logger[ContextSink[S]] {}

input

• self : Logger[S] - Base logger that should gain shared fields.
• fields : Array[Field] - Structured fields attached to every emitted record.

output

• Logger[ContextSink[S]] - New logger value whose visible sink type becomes ContextSink[S] and prepends shared fields at write time.

Explanation

Detailed rules explaining key parameters and behaviors

• bind(...) delegates directly to with_context_fields(...); it is an alias, not a different implementation.
• The original logger value is not mutated; a derived wrapped logger is returned.
• The returned logger changes visible type from Logger[S] to Logger[ContextSink[S]] because the sink pipeline is extended with stored shared fields.
• Stored target, minimum level, and timestamp behavior are preserved while the sink pipeline changes.
• Shared fields are applied to every later log call emitted through the returned logger.
• When a log call also passes per-record fields, the shared bound fields are prepended before those per-call fields because bind(...) inherits the same merge order as with_context_fields(...).
• This alias is useful when you prefer shorter chaining syntax in application code.

How to Use

Here are some specific examples provided.

When Bind Shared Request Context

When a logger should carry stable fields through a flow:

let request_logger = Logger::new(console_sink(), target="api")
  .bind([field("request_id", "req-42")])

In this example, subsequent writes automatically include request_id.

When Prefer Shorter Chaining Syntax

When a context-bound child logger should stay readable:

let worker = Logger::new(console_sink(), target="app")
  .child("worker")
  .bind([field("component", "worker")])

In this example, bind(...) communicates intent without changing underlying behavior.

And the returned logger still keeps the same target and level-gating behavior as the source logger.

Error Case

e.g.:

• If fields is empty, the returned logger remains valid and simply adds no extra metadata.

• If duplicate field keys are bound, all copies are preserved for downstream formatting or inspection.

Notes

1. Use bind(...) and with_context_fields(...) interchangeably; choose the one that reads better in context.

2. This alias exists for ergonomics, not for different semantics.

3. Use with_context_fields(...) when the longer name makes the sink-type change to ContextSink[S] clearer at the call site.