Add CompositeEventSourceBuilder #28
Merged
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
We currently have MergedEventSource to compose multiple event sources with the same event type, but it’s unergonomic because it takes an array of event sources, but you can’t construct an array of heterogeneous event sources due to limitations on protocols with associated types. The current workaround is to explicitly wrap the members of the array in AnyEventSource, but explicit use of type erasure in clients is unpleasant. Using a builder lets us take each individual event source as a generic parameter and handle the type erasure internally. I called it CompositeEventSourceBuilder rather than MergedEventSource by analogy to CompositeDisposable.
JensAyton
force-pushed
the
composite-event-source-builder
branch
from
952166e to
6f680f4
Compare
JensAyton
commented
May 27, 2019
| /// Builds an event source that composes all the event sources that have been added to the builder. | ||
| /// | ||
| /// - Returns: An event source which represents the composition of the builder’s input event sources. The type | ||
| /// of this source is an implementation detail; consumers should avoid spelling it out if possible. |
There was a problem hiding this comment.
In particular, I’d like the return type to be some EventSource<.Event == Event>, but Swift 5.1 will only have unconstrained opaque types.
|
Now with unit tests. In order to let the existing |
JensAyton
force-pushed
the
composite-event-source-builder
branch
from
e662dea to
2755c9f
Compare
JensAyton
force-pushed
the
composite-event-source-builder
branch
from
2755c9f to
7fb96ff
Compare
Codecov Report
@@ Coverage Diff @@
## master #28 +/- ##
==========================================
+ Coverage 96.9% 96.96% +0.06%
==========================================
Files 35 36 +1
Lines 839 858 +19
==========================================
+ Hits 813 832 +19
Misses 26 26
Continue to review full report at Codecov.
|
pettermahlen
approved these changes
May 27, 2019
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
We currently have
MergedEventSourceto compose multiple event sources with the same event type, but it’s unergonomic because it takes an array of event sources, and you can’t construct an array of heterogeneous event sources due to limitations on protocols with associated types.The current workaround is to explicitly wrap the members of the array in
AnyEventSource, but explicit use of type erasure in clients is unpleasant.Using a builder lets us take each individual event source as a generic parameter and handle the type erasure internally.
I called it
CompositeEventSourceBuilderrather thanMergedEventSourceBuilderby analogy toCompositeDisposable.