Clojure comp, partial, juxt & complement — Composition & Partial | Episode 17

Clojure gives you a handful of tiny functions for building bigger functions — comp, partial, juxt, and complement. Learn them once and you'll reach for them every day. In this episode we cover comp to compose functions right-to-left, partial to pre-fill arguments, juxt to apply many functions to one input, and complement to flip any predicate. Then we glue them together into a small data-cleaning pipeline. Phase 3 continues — the Functional Core! Student code: https://github.com/GoCelesteAI/clojure-for-beginners/tree/main/episode17 Every keystroke is shown on screen with generous pauses so you can follow along at your own pace. What You'll Learn: - comp — compose functions right-to-left - partial — pre-fill the first arguments of a function - juxt — apply many functions to one input, collect results in a vector - complement — flip any predicate to its opposite - Point-free pipelines — build out of small, named pieces Timestamps: 0:00 - Intro 0:12 - Preview: comp, partial, juxt, complement 0:32 - Start the REPL 0:40 - comp in the REPL 0:54 - partial in the REPL 1:08 - juxt in the REPL 1:24 - complement in the REPL 1:38 - Exit REPL 1:43 - Write composition.clj in Neovim 2:05 - comp section 3:18 - partial section 4:35 - juxt section 5:59 - complement section 6:55 - clean-name pipeline 8:12 - Partial + map prefix tag 8:56 - Run with :!clj -M % 9:00 - Output walked through 9:55 - Review 10:00 - Recap 10:35 - What's next: Episode 18 Key Takeaways: 1. comp composes functions right-to-left. (comp f g) is the same as #(f (g %)). 2. partial pre-fills the first arguments — perfect for passing "specialized" fns to map. 3. juxt applies many fns to one input and returns a vector of the results. 4. complement flips any predicate. Pair with filter, remove, drop-while, etc. Phase 3 continues! Next up, Episode 18 — transducers, for performance-friendly pipelines without intermediate collections. Taught by CelesteAI. Like and subscribe for more Clojure tutorials!