Reflecting on Random Generation

on YouTube ↗27m

" summary

Presents reflective generators that combine free generators + partial monadic profunctors so a generator can run “backwards” to recover random choices that could produce a value. Implements interpretations on top of Freer/QuickCheck Gen, adds lmap/prune annotations (often lenses/prisms), and converts a BST generator to reflect, check, and extract a choice trace. Demonstrates choice-based shrinking, example-based reweighting (Inputs from Hell extension), and property tests for soundness/completeness; prototypes succeed on BST examples and related demos, artifacts available.

AI-written summary · about

" chapters (6)

1. 0:00Free generators intro
2. 2:05Bidirectional programs & profunctors
3. 8:21Combining generators & logic
4. 12:16Reflective generators intro
5. 18:54Correctness & limits
6. 22:03Q&A

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