7e3e7cf5d9
This PR adds `cbv` annotations to some iterator and string operations. --------- Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
113 lines
2.4 KiB
Text
113 lines
2.4 KiB
Text
import Std
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-- Use opaque constants so that cbv_eval is the ONLY way cbv can reduce them.
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-- After erasure, cbv makes no progress and the goal must be closed manually.
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opaque myConst : Nat
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/-- warning: declaration uses `sorry` -/
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#guard_msgs in
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@[cbv_eval] theorem myConst_eq : myConst = 42 := sorry
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-- Before erasure: cbv reduces myConst to 42 via cbv_eval
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example : myConst = 42 := by cbv
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-- Warning when erasing a theorem that doesn't have [cbv_eval]
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theorem not_cbv (n : Nat) : n = n := rfl
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/-- warning: `not_cbv` does not have the `[cbv_eval]` attribute -/
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#guard_msgs in
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attribute [-cbv_eval] not_cbv
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-- Basic erasure (no section — permanent)
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attribute [-cbv_eval] myConst_eq
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-- After erasure: cbv can't reduce myConst, so the goal isn't closed
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example : myConst = 42 := by
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cbv -- makes no progress
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exact myConst_eq
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-- Scoping: erasure inside a section is reverted
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opaque myConst2 : Nat
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/-- warning: declaration uses `sorry` -/
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#guard_msgs in
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@[cbv_eval] theorem myConst2_eq : myConst2 = 100 := sorry
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section
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attribute [-cbv_eval] myConst2_eq
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-- Inside section: cbv can't reduce
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/--
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trace: ⊢ myConst2 = 100
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---
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warning: declaration uses `sorry`
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-/
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#guard_msgs in
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example : myConst2 = 100 := by
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cbv
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trace_state
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sorry
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end
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-- Outside section: cbv_eval is back
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example : myConst2 = 100 := by cbv
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-- Erasure of inverted theorem
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opaque myConst3 : Nat
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/-- warning: declaration uses `sorry` -/
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#guard_msgs in
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@[cbv_eval ←] theorem myConst3_eq : 7 = myConst3 := sorry
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example : myConst3 = 7 := by cbv
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section
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attribute [-cbv_eval] myConst3_eq
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/--
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trace: ⊢ myConst3 = 7
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---
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warning: declaration uses `sorry`
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-/
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#guard_msgs in
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example : myConst3 = 7 := by
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cbv
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trace_state
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sorry
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end
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-- Reverted after section
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example : myConst3 = 7 := by cbv
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-- Erasure with multiple cbv_eval rules: erase only one
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opaque myFn : Nat → Nat
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/-- warning: declaration uses `sorry` -/
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#guard_msgs in
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@[cbv_eval] theorem myFn_zero : myFn 0 = 1 := sorry
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/-- warning: declaration uses `sorry` -/
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#guard_msgs in
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@[cbv_eval] theorem myFn_one : myFn 1 = 0 := sorry
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example : myFn 0 = 1 := by cbv
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example : myFn 1 = 0 := by cbv
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section
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attribute [-cbv_eval] myFn_zero
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-- myFn_zero is erased, so cbv can't reduce myFn 0
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/--
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trace: ⊢ myFn 0 = 1
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---
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warning: declaration uses `sorry`
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-/
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#guard_msgs in
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example : myFn 0 = 1 := by
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cbv
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trace_state
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sorry
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-- myFn_one is still active
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example : myFn 1 = 0 := by cbv
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end
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