mirror of
https://github.com/Nanaloveyuki/BitLogger.git
synced 2026-05-30 23:52:27 +00:00
Nanaloveyuki
77 lines
1.9 KiB
Markdown
77 lines
1.9 KiB
Markdown
---
|
|
name: identity-patch
|
|
group: api
|
|
category: patching
|
|
update-time: 20260512
|
|
description: Create a reusable record patch that returns records unchanged.
|
|
key-word:
|
|
- patch
|
|
- transform
|
|
- record
|
|
- public
|
|
---
|
|
|
|
## Identity-patch
|
|
|
|
Create a `RecordPatch` that returns the input record unchanged. This helper is useful as a neutral default, a placeholder in configuration, or a composition baseline.
|
|
|
|
### Interface
|
|
|
|
```moonbit
|
|
pub fn identity_patch() -> RecordPatch {}
|
|
```
|
|
|
|
#### output
|
|
|
|
- `RecordPatch` - Patch function that returns the original record without modification.
|
|
|
|
### Explanation
|
|
|
|
Detailed rules explaining key parameters and behaviors
|
|
|
|
- The returned patch is a pure pass-through transformation.
|
|
- It does not allocate new fields or rewrite existing properties.
|
|
- This helper is useful when a patch slot must be provided but no mutation is currently needed.
|
|
- It also works as a safe baseline inside `compose_patches(...)` pipelines.
|
|
|
|
### How to Use
|
|
|
|
Here are some specific examples provided.
|
|
|
|
#### When Need A Neutral Patch
|
|
|
|
When a logger pipeline expects a patch but no rewrite is required yet:
|
|
```moonbit
|
|
let logger = Logger::new(console_sink())
|
|
.with_patch(identity_patch())
|
|
```
|
|
|
|
In this example, the logger shape stays consistent while records remain unchanged.
|
|
|
|
#### When Build Patches Conditionally
|
|
|
|
When a branch may or may not enable a real patch:
|
|
```moonbit
|
|
let patch = if enable_redaction {
|
|
redact_field("token")
|
|
} else {
|
|
identity_patch()
|
|
}
|
|
```
|
|
|
|
In this example, caller code can still treat the result as a normal `RecordPatch`.
|
|
|
|
### Error Case
|
|
|
|
e.g.:
|
|
- `identity_patch()` has no failure path; it simply returns the original record.
|
|
|
|
- If a caller expects visible transformation, using this patch will intentionally produce none.
|
|
|
|
### Notes
|
|
|
|
1. Use this helper when you want a no-op patch with explicit intent instead of a custom inline closure.
|
|
|
|
2. It is especially useful in conditional or generated patch pipelines.
|
|
|