# json.patch

> A module of json_mlake's API.

## Functions

### `apply_patch`

```mojo
def apply_patch(document: Value, patch: Value) -> Value
```

Apply a JSON Patch (RFC 6902) to a document.

The patch is a JSON array of operations. Each operation has:
- "op": The operation ("add", "remove", "replace", "move", "copy", "test")
- "path": JSON Pointer to the target location
- "value": The value (for add, replace, test)
- "from": Source path (for move, copy)

Operations are applied in order, and the whole patch either
succeeds or changes nothing: the document is never edited in
place, so an operation that raises leaves the caller's value as it
was. The failure names the operation's index, because a patch that
only says "key not found" is hard to place in a long list.

Example:
var doc = loads('{"name":"Alice"}')
var patch = loads('[{"op":"add","path":"/age","value":30}]')
var result = apply_patch(doc, patch)
Result is `{"name":"Alice","age":30}`.

Args:

- `document`: The original JSON document.
- `patch`: Array of patch operations.

### `merge_patch`

```mojo
def merge_patch(target: Value, patch: Value) -> Value
```

Apply a JSON Merge Patch (RFC 7396) to a document.

Merge patch rules:
- If patch is not an object, it replaces target entirely
- null values in patch remove keys from target
- Other values are recursively merged

Example:
var target = loads('{"a":1,"b":2}')
var patch = loads('{"b":null,"c":3}')
var result = merge_patch(target, patch)
Result is `{"a":1,"c":3}`.

Args:

- `target`: The original document.
- `patch`: The merge patch to apply.

### `create_merge_patch`

```mojo
def create_merge_patch(source: Value, target: Value) -> Value
```

Create a merge patch that transforms source into target.

Example:
var source = loads('{"a":1,"b":2}')
var target = loads('{"a":1,"c":3}')
var patch = create_merge_patch(source, target)
Result is `{"b":null,"c":3}`.

Args:

- `source`: The original document.
- `target`: The desired result.