The `params` hashmap provides the following fields about each parameter:
|!Param Field Name |!Description |
|`byName` |Provided if the parameter should be referenced by name. The value can be `true` or `"default"` to indicate that the parameter should accept anonymous parameters |
|`type` |The type of the parameter, from `text` or `tiddler` (used for dependency tracking) |
|`optional` |`true` if the parameter is optional |
The `code` function is called with the following parameters:
|!Param Name |!Description |
|`type` |The target MIME type for rendering the macro |
|`tiddler` |The tiddler in whose context the macro is being rendered |