Problem/Motivation
Sometimes I wish a process plugin that is set to "handle_multiples" didn't handle multiples.
Proposed resolution
I ran into another issue that proposes an "iterate" process plugin.
✨
Add an iterate process plugin
Needs review
. While reviewing that issue, it seemed like a lot of complexity that I'd rather defer to the sub_process plugin, which already handles this kind of thing. The problem is that sub_process requires an array of arrays as input.
A simple way around this would be to add a "wrapper" process plugin that could turn an array into an array of arrays. Then the process plugin I wished didn't handle multiples could be used inside a sub_process. Boom! Oh, and then the "wrapper" process plugin could "unwrap" after the sub_process if needed.
Keeping the "hard part" in sub_process instead of introducing a new "iterate" process plugin makes this very easy to unit test. It's also possible that wrapping or unwrapping a value could be useful outside the context of iteration/sub_processing.
Example:
* For an input array of arrays, flatten each of child arrays.
*
* Assume the input array my_array is:
* [
* ['a', 'b', ['c, 'd']],
* [1, 2, [3, 4]],
* ]
*
* And we want to transform this into:
* [
* ['a', 'b', 'c, 'd'],
* [1, 2, 3, 4],
* ]
*
* Since the flatten plugin is designed to "handle_multiples",
* doing this:
*
* @code
* flatten_wont_work:
* plugin: flatten
* source: my_array
* @endcode
*
* Will result in a single array:
* ['a', 'b', 'c', 'd', 1, 2, 3, 4]
*
* This is where the wrapper plugin can save the day. We can
* call wrap on my_array, then use a sub_process, and finally
* unwrap the result of the sub_process.
*
* @code
* my_desired_output:
* -
* plugin: wrapper
* method: wrap
* source: my_array
* key: element
* -
* plugin: sub_process
* process:
* '0':
* plugin: flatten
* source: element # This should match the 'key' used when wrapping.
* -
* plugin: wrapper
* method: unwrap
* @endcode
*
* In general terms, the most powerful use case is when you wish
* that an existing process plugin didn't "handle_multiples". In such
* a case the pattern above can be used: wrap, sub_process, unwrap.
Remaining tasks
N/A
User interface changes
N/A
API changes
New "wrapper" process plugin
Data model changes
N/A