Creates a stream by repeatedly calling a lazily evaluated function#1139
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hearnadam
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Apr 12, 2025
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Thanks for your contribution! This definitely could be useful.
| Emit.valueWith(c.take(_chunkSize))(Loop.continue(c.dropLeft(_chunkSize))) | ||
| v.map(seq => emitResized(seq, chunkSize)) | ||
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| private def emitResized[V](seq: Seq[V], chunkSize: Int)(using tag: Tag[Emit[Chunk[V]]], frame: Frame): Unit < Emit[Chunk[V]] = |
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I don't think this is quite semantically correct for the repeat case as it may produce chunks like this:
given: repeatPresent(Chunk(1, 2, 3, 4), 3)
outcome: Stream(Chunk(1, 2, 3), Chunk(4), Chunk(1, 2, 3), Chunk(4)...)
In my opinion, it's reasonable for .rechunk to be used after the repeat operator, given rechunking will happen across suspension.
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Thanks for the reply. I've changed to calling rechunk.
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| "repeatPresent" - { | ||
| var i = 0 |
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Please avoid mutability outside the scope of a single test if possible 🙏 it makes parallelizing/refactoring tests difficult.
Perhaps you can use the Var effect?
…ntil the return is absent.
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hearnadam
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thank you @vladpo! |
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…1139) Creates a stream by repeatedly calling a lazily evaluated function, until the return is absent. <!-- PRs require an approval from any of the core contributors, other than the PR author. Include this header if applicable: Fixes #issue1, #issue2, ... --> ### Problem <!-- Explain here the context, and why you're making this change. What is the problem you're trying to solve? --> Stream emit an effect until some end state offers no more values. ### Solution <!-- Describe your solution. Focus on helping reviewers understand your technical approach and implementation decisions. --> repeatPresent is a factory method in the Stream class that creates a stream by repeatedly calling a function until it returns an absent value 1. Create a stream from a function that may return values multiple times 2. Automatically terminate the stream when the function returns an absent value 3. Control the chunk size of emitted values for performance optimization ### Notes <!-- Add any important additional information as bullet points, such as: - Implementation details reviewers should know about - Open questions and concerns - Limitations -->
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Creates a stream by repeatedly calling a lazily evaluated function, until the return is absent.
Problem
Stream emit an effect until some end state offers no more values.
Solution
repeatPresent is a factory method in the Stream class that creates a stream by repeatedly calling a function until it returns an absent value
Notes