26ad4d6972
This PR extracts the functional (lambda) passed to `brecOn` in structural recursion into a named `_f` helper definition (e.g. `foo._f`), similar to how well-founded recursion uses `._unary`. This way the functional shows up with a helpful name in kernel diagnostics rather than as an anonymous lambda. The `_f` definition is added with `.abbrev` kernel reducibility hints and the `@[reducible]` elaborator attribute, so the kernel unfolds it eagerly after `brecOn` iota-reduces. For inductive predicates, the previous inline lambda behavior is kept. To ensure that parent definitions still get the correct reducibility height (since `getMaxHeight` ignores `.abbrev` definitions), each `_f`'s body height is registered via a new `defHeightOverrideExt` environment extension. `getMaxHeight` checks this extension for all definitions, making the height computation transparent to the extraction. This change improves code size (a bit). It may regress kernel reduction times, especially if a function defined by structural recursion is used in kernel reduction proofs on the hot path. Functions defined by structural recursion are not particularly fast to reduce anyways (due to the `.brecOn` construction), so already now it may be worth writing a kernel-reduction-friendly function manually (using the recursor directly, avoiding overloaded operations). This change will guide you in knowing which function to optimize. 🤖 Generated with [Claude Code](https://claude.com/claude-code) --------- Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
34 lines
595 B
Text
34 lines
595 B
Text
def myAdd : Nat → Nat → Nat
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| 0, m => m
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| n+1, m => (myAdd n m).succ
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set_option pp.motives.pi false
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#print myAdd._f
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set_option pp.motives.pi true
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#print myAdd._f
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set_option linter.unusedVariables false in
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theorem ex : ∀ {α β : Sort u} (h : α = β) (a : α), cast h a ≍ a
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| α, _, rfl, a => HEq.refl a
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set_option pp.motives.nonConst false
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#print ex
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set_option pp.motives.nonConst true
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#print ex
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noncomputable def fact (n : Nat) : Nat :=
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Nat.recOn n 1 (fun n acc => (n+1)*acc)
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set_option pp.motives.all false
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#print fact
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set_option pp.motives.all true
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#print fact
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