81ea922025
This PR renames `String.Pos` to `String.Pos.Raw`. After an abbreviated deprecation cycle, we will then rename `String.ValidPos` to `String.Pos`.
160 lines
5 KiB
Text
160 lines
5 KiB
Text
/-
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Copyright (c) 2020 Microsoft Corporation. All rights reserved.
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Released under Apache 2.0 license as described in the file LICENSE.
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Author: Leonardo de Moura
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-/
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module
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prelude
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public import Init.Data.Repr
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public import Init.Data.Option.Basic
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public section
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open Sum Subtype Nat
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open Std
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/--
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Types that can be converted into a string for display.
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There is no expectation that the resulting string can be parsed back to the original data (see
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`Repr` for a similar class with this expectation).
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-/
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class ToString (α : Type u) where
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/-- Converts a value into a string. -/
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toString : α → String
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export ToString (toString)
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-- This instance is needed because `id` is not reducible
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instance {α} [ToString α] : ToString (id α) :=
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inferInstanceAs (ToString α)
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instance {α} [ToString α] : ToString (Id α) :=
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inferInstanceAs (ToString α)
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instance : ToString String :=
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⟨fun s => s⟩
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instance : ToString Substring :=
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⟨fun s => Substring.Internal.toString s⟩
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instance : ToString Char :=
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⟨fun c => Char.toString c⟩
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instance : ToString Bool :=
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⟨fun b => cond b "true" "false"⟩
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instance {p : Prop} : ToString (Decidable p) := ⟨fun h =>
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match h with
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| Decidable.isTrue _ => "true"
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| Decidable.isFalse _ => "false"⟩
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/--
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Converts a list into a string, using `ToString.toString` to convert its elements.
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The resulting string resembles list literal syntax, with the elements separated by `", "` and
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enclosed in square brackets.
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The resulting string may not be valid Lean syntax, because there's no such expectation for
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`ToString` instances.
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Examples:
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* `[1, 2, 3].toString = "[1, 2, 3]"`
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* `["cat", "dog"].toString = "[cat, dog]"`
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* `["cat", "dog", ""].toString = "[cat, dog, ]"`
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-/
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protected def List.toString [ToString α] : List α → String
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| [] => "[]"
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| [x] => String.Internal.append (String.Internal.append "[" (toString x)) "]"
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| x::xs => String.push (xs.foldl (fun l r => String.Internal.append (String.Internal.append l ", ") (toString r))
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(String.Internal.append "[" (toString x))) ']'
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instance {α : Type u} [ToString α] : ToString (List α) :=
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⟨List.toString⟩
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instance : ToString PUnit.{u+1} :=
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⟨fun _ => "()"⟩
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instance {α : Type u} [ToString α] : ToString (ULift.{v} α) :=
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⟨fun v => toString v.1⟩
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instance : ToString Unit :=
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⟨fun _ => "()"⟩
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instance : ToString Nat :=
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⟨fun n => Nat.repr n⟩
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instance : ToString String.Pos.Raw :=
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⟨fun p => Nat.repr p.byteIdx⟩
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instance : ToString Int where
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toString
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| Int.ofNat m => toString m
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| Int.negSucc m => String.Internal.append "-" (toString (succ m))
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instance (n : Nat) : ToString (Fin n) :=
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⟨fun f => toString (Fin.val f)⟩
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instance : ToString UInt8 :=
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⟨fun n => toString n.toNat⟩
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instance : ToString UInt16 :=
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⟨fun n => toString n.toNat⟩
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instance : ToString UInt32 :=
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⟨fun n => toString n.toNat⟩
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instance : ToString UInt64 :=
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⟨fun n => toString n.toNat⟩
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instance : ToString USize :=
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⟨fun n => toString n.toNat⟩
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instance : ToString Format where
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toString f := f.pretty
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def addParenHeuristic (s : String) : String :=
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if String.Internal.isPrefixOf "(" s || String.Internal.isPrefixOf "[" s || String.Internal.isPrefixOf "{" s || String.Internal.isPrefixOf "#[" s then s
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else if !(String.Internal.any s Char.isWhitespace) then s
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else String.Internal.append (String.Internal.append "(" s) ")"
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instance {α : Type u} [ToString α] : ToString (Option α) := ⟨fun
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| none => "none"
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| (some a) => String.Internal.append (String.Internal.append "(some " (addParenHeuristic (toString a))) ")"⟩
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instance {α : Type u} {β : Type v} [ToString α] [ToString β] : ToString (Sum α β) := ⟨fun
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| (inl a) => String.Internal.append (String.Internal.append "(inl " (addParenHeuristic (toString a))) ")"
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| (inr b) => String.Internal.append (String.Internal.append "(inr " (addParenHeuristic (toString b))) ")"⟩
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instance {α : Type u} {β : Type v} [ToString α] [ToString β] : ToString (α × β) := ⟨fun (a, b) =>
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String.Internal.append
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(String.Internal.append
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(String.Internal.append
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(String.Internal.append "(" (toString a))
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", ")
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(toString b))
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")"⟩
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instance {α : Type u} {β : α → Type v} [ToString α] [∀ x, ToString (β x)] : ToString (Sigma β) := ⟨fun ⟨a, b⟩ =>
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String.Internal.append
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(String.Internal.append
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(String.Internal.append
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(String.Internal.append "⟨" (toString a))
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", ")
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(toString b))
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"⟩"⟩
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instance {α : Type u} {p : α → Prop} [ToString α] : ToString (Subtype p) := ⟨fun s =>
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toString (val s)⟩
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instance [ToString ε] [ToString α] : ToString (Except ε α) where
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toString
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| Except.error e => String.Internal.append "error: " (toString e)
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| Except.ok a => String.Internal.append "ok: " (toString a)
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instance [Repr ε] [Repr α] : Repr (Except ε α) where
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reprPrec
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| Except.error e, prec => Repr.addAppParen ("Except.error " ++ reprArg e) prec
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| Except.ok a, prec => Repr.addAppParen ("Except.ok " ++ reprArg a) prec
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