01dbbeed99
This PR adjusts the experimental module system to not export the bodies of `def`s unless opted out by the new attribute `@[expose]` on the `def` or on a surrounding `section`. --------- Co-authored-by: Markus Himmel <markus@lean-fro.org>
50 lines
1.3 KiB
Text
50 lines
1.3 KiB
Text
/-
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Copyright (c) 2024 Lean FRO. All rights reserved.
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Released under Apache 2.0 license as described in the file LICENSE.
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Authors: Kim Morrison
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-/
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module
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prelude
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import Init.Core
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namespace Function
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/--
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Transforms a function from pairs into an equivalent two-parameter function.
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Examples:
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* `Function.curry (fun (x, y) => x + y) 3 5 = 8`
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* `Function.curry Prod.swap 3 "five" = ("five", 3)`
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-/
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@[inline, expose]
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def curry : (α × β → φ) → α → β → φ := fun f a b => f (a, b)
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/--
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Transforms a two-parameter function into an equivalent function from pairs.
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Examples:
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* `Function.uncurry List.drop (1, ["a", "b", "c"]) = ["b", "c"]`
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* `[("orange", 2), ("android", 3) ].map (Function.uncurry String.take) = ["or", "and"]`
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-/
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@[inline, expose]
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def uncurry : (α → β → φ) → α × β → φ := fun f a => f a.1 a.2
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@[simp]
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theorem curry_uncurry (f : α → β → φ) : curry (uncurry f) = f :=
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rfl
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@[simp]
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theorem uncurry_curry (f : α × β → φ) : uncurry (curry f) = f :=
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funext fun ⟨_a, _b⟩ => rfl
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@[simp]
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theorem uncurry_apply_pair {α β γ} (f : α → β → γ) (x : α) (y : β) : uncurry f (x, y) = f x y :=
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rfl
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@[simp]
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theorem curry_apply {α β γ} (f : α × β → γ) (x : α) (y : β) : curry f x y = f (x, y) :=
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rfl
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end Function
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