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4 changes: 4 additions & 0 deletions CHANGELOG.md
Original file line number Diff line number Diff line change
Expand Up @@ -49,6 +49,10 @@ Non-backwards compatible changes
* Moved `Data.Vec.Equality` to `Data.Vec.Relation.Equality` (see "Deprecated
features" section for explanation)

* Changed Data.Nat.Divisibility's `_|_` from data to record. As a consequence,
the two parameters are not implicit arguments of the constructor anymore (but
such values can be destructed using a let-binding rather than a with-clause).

Deprecated features
-------------------

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15 changes: 8 additions & 7 deletions src/Data/Nat/Divisibility.agda
Original file line number Diff line number Diff line change
Expand Up @@ -30,8 +30,10 @@ open import Function

infix 4 _∣_ _∤_

data _∣_ : ℕ → ℕ → Set where
divides : {m n : ℕ} (q : ℕ) (eq : n ≡ q * m) → m ∣ n
record _∣_ (m n : ℕ) : Set where
constructor divides
field quotient : ℕ
equality : n ≡ quotient * m

_∤_ : Rel ℕ _
m ∤ n = ¬ (m ∣ n)
Expand Down Expand Up @@ -61,11 +63,10 @@ quotient (divides q _) = q
divides (q * p) (sym (*-assoc q p _))

∣-antisym : Antisymmetric _≡_ _∣_
∣-antisym (divides {n = zero} _ _) (divides q refl) = *-comm q 0
∣-antisym (divides p eq) (divides {n = zero} _ _) =
trans (*-comm 0 p) (sym eq)
∣-antisym (divides {n = suc _} p eq₁) (divides {n = suc _} q eq₂) =
≤-antisym (∣⇒≤ (divides p eq₁)) (∣⇒≤ (divides q eq₂))
∣-antisym {m} {0} _ (divides q eq) = trans eq (*-comm q 0)
∣-antisym {0} {n} (divides p eq) _ = sym (trans eq (*-comm p 0))
∣-antisym {suc m} {suc n} (divides p eq₁) (divides q eq₂) =
≤-antisym (∣⇒≤ (divides p eq₁)) (∣⇒≤ (divides q eq₂))

∣-isPreorder : IsPreorder _≡_ _∣_
∣-isPreorder = record
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