What changed

  The old chapter showed call/=.. as thin pass-through wrappers (relate(P,A,B) :- call(P,A,B)) — exactly the
  "artificial wrapping with the same args" you named. The reworked chapter makes the meta-call load-bearing: each
  task is something you genuinely cannot write without it, and each prose section shows the painful without-it
  version first.

  ┌─────┬──────────────┬──────────────────────────────────────────────┬────────────────────┐
  │  #  │   Exercise   │                   The job                    │ Library equivalent │
  ├─────┼──────────────┼──────────────────────────────────────────────┼────────────────────┤
  │ 01  │ all_pass/2   │ every element satisfies a test you're handed │ forall             │
  ├─────┼──────────────┼──────────────────────────────────────────────┼────────────────────┤
  │ 02  │ keep/3       │ filter to elements satisfying a predicate    │ include/3          │
  ├─────┼──────────────┼──────────────────────────────────────────────┼────────────────────┤
  │ 03  │ apply_each/3 │ transform every element via a predicate      │ maplist/3          │
  ├─────┼──────────────┼──────────────────────────────────────────────┼────────────────────┤
  │ 04  │ apply_op/3   │ dispatch by a name held in data (=.. + call) │ —                  │
  └─────┴──────────────┴──────────────────────────────────────────────┴────────────────────┘

  The unifying idea is stated up front: one rule that works for any predicate you pass it. Exercise 01's prose
  puts the duplicated all_positive/all_even recursions side by side, then collapses them into one all_pass.
  Exercise 02 motivates call's extra-args feature through partial application (above(3) as a one-arg test built
  from data). Exercise 04 frames =.. dispatch against the one-clause-per-name table it replaces.

  Dropped, honestly

  copy_term/2 is gone — its real uses (meta-interpreters, term rewriting) are beyond where the curriculum is, and
  "fill a template twice" was the contrived framing you reacted to. It's noted in the design doc as deferred to a
  later, motivated home rather than faked here. (functor/3 construct stays deferred too — that one's a genuine
  plgc bug.)

  So: not you, and not "need more language first." The exercises owed you the payoff and didn't deliver it. They
  do now.

  just ci green at 58. Docs (README, ROADMAP, design matrix) updated, and I recorded the principle — teach the
  use, not the mechanism; defer rather than fake-motivate — so it guides chapters 12–16.

navicore merged commit 6074827323 into main

2026-06-22 13:44:13 +00:00

navicore deleted branch chapter11

2026-06-22 13:44:13 +00:00

navicore referenced this pull request from a commit

2026-06-22 13:44:14 +00:00

Merge pull request 'chapter 11 passed' (#11) from chapter11 into main