[jph00]

Build BPL expressions with fn(*parts), using Python functions, operators, data, lists and grouped tuples through BPL's parser and evaluator. Alpha/omega parts create dfns; numeric scripts keep their contextual meanings. Function attributes form trains, function calls compose, and unique prefixes work with completion. Use | for argument binding in place of the old function bitwise-OR overload and .left(...). Python numeric kinds and weak scalars are preserved. The Python tutorial includes RMSPE and aligned table sampling examples.

Compatible ragged Each cells and dfn Key groups run batched while large cells retain the cheaper ordered path. Mix and batching share uniform assembly. Mapped broadcasts reuse padded inputs, small fused groups compile after enough accumulated work, and planning/JIT constants retain exact integer bits. Python and native reference checks share one runner. See “Expressions from Python parts” and “Word functions” in Python, “Transformations keep whole-array work” in Foundations, and “Tests and reference data” in DEV.

Replace ⍺ ⍵ ⍳ ⍴ ⍟ ⋄ with α ω ι ρ ⊛ ◇ throughout BPL and keyboard entry, preserve their appearance in both fonts, and support ordinary Python operators consistently across expression parts. Unused Option-Shift letter chords type additional Greek letters without changing existing bindings or the keyboard-map docs page.