This guide teaches transducers, lazy sequences, functional composition, and threading macros through practical musical examples. The musical domain makes these concepts natural and intuitive, demonstrating how functional programming patterns solve real-world problems.
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Very cool. Thanks for the detailed walk through your design philosophy, and thank you for the tool too. I love the idea of agreeing structures to streams in an intuitive way so you can think about your piece the way that comes naturally to you.
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Glad you like it! There aren’t that many Clojure transducer tutorials out there, so I thought this one might be useful. It’s central infrastructure for Ooloi.
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All the writing for Ooloi is excellent. And this is no exception. What a great way to step through the concept. I also love that you stress the composable tuple. Do you actually enforce that structure in the Ooloi code, @Peter_Bengtson ?
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Transducers are something I don’t understand yet, so I’m slotting a good hour or more with your tutorial. Big gratitude.
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Thank you all for the kind words – I’m genuinely glad the guide has proved useful. Writing it was as much a way of clarifying my own thinking as of explaining the code; these patterns only really come alive when they’re described in living terms, not just drawn as diagrams.
As for enforcing patterns: I’m a pragmatist, not a gatekeeper. There’s no way – and no sense – in trying to compel anyone to ‘use transducers properly’. The architecture makes it possible to use them well, but it doesn’t make it compulsory. As the old line goes: you can’t carry someone into Paradise. 
And I’m still very much on a journey of discovery myself. After re-engineering the timewalker transducer to be truly zero-consing and push-only, it struck me that the hash-cons daemon wasn’t taking full advantage – it was still relying on a lazy sequence at the top level. So I refactored the daemon and updated ADR-0029 accordingly. That sort of iterative self-correction keeps the system honest: the architecture teaching me how to improve my own earlier code.
Ooloi keeps reminding me that elegance isn’t something you impose – it’s something you uncover when everything finally aligns.
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