Function Composition in Programming Languages
summary
Argues that combinators go far beyond unary compose and that modern array languages (J, Dyalog APL, bqn) are the most practical hosts, claiming bqn has the richest combinator set. Demonstrates exact-match Mastermind and “sum of special squares” solved pointfree using B and B1 combinators, maps those solutions into Rust and C++ (including a C++ Blackbird library) and shows transform‑reduce / inner‑product equivalences. Presents four different implementations of the same problem, runs live bqnpad tests that pass, and shows the combinator patterns actually compose and perform.
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chapters (12)
- 0:00Introduction and speaker background
- 3:14Discovery of combinator programming
- 11:58Brief history of combinatory logic
- 14:07Brief history of array languages
- 16:12Combinators in array languages
- 19:20What is a combinator?
- 24:13Elementary combinators explained
- 31:13Example 1: Exact matches in Mastermind
- 37:11Example 2: Counting positive and negative integers
- 42:04Example 3: Sum of squares of special elements
- 53:30Translating combinators to system languages
- 59:07Conclusion and key takeaways
