dc1a1c8540
See issue #1664 This is just the first step to implement proposal described at issue #1664.
108 lines
3.3 KiB
Text
108 lines
3.3 KiB
Text
/-
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Copyright (c) 2016 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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prelude
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import init.data.string.basic init.data.bool.basic init.data.subtype.basic
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import init.data.unsigned.basic init.data.prod init.data.sum.basic init.data.nat.div
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open sum subtype nat
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universes u v
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class has_repr (α : Type u) :=
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(repr : α → string)
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def repr {α : Type u} [has_repr α] : α → string :=
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has_repr.repr
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instance : has_repr bool :=
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⟨λ b, cond b "tt" "ff"⟩
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instance {p : Prop} : has_repr (decidable p) :=
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-- Remark: type class inference will not consider local instance `b` in the new elaborator
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⟨λ b : decidable p, @ite p b _ "tt" "ff"⟩
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protected def list.repr_aux {α : Type u} [has_repr α] : bool → list α → string
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| b [] := ""
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| tt (x::xs) := repr x ++ list.repr_aux ff xs
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| ff (x::xs) := ", " ++ repr x ++ list.repr_aux ff xs
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protected def list.repr {α : Type u} [has_repr α] : list α → string
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| [] := "[]"
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| (x::xs) := "[" ++ list.repr_aux tt (x::xs) ++ "]"
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instance {α : Type u} [has_repr α] : has_repr (list α) :=
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⟨list.repr⟩
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instance : has_repr unit :=
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⟨λ u, "star"⟩
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instance {α : Type u} [has_repr α] : has_repr (option α) :=
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⟨λ o, match o with | none := "none" | (some a) := "(some " ++ repr a ++ ")" end⟩
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instance {α : Type u} {β : Type v} [has_repr α] [has_repr β] : has_repr (α ⊕ β) :=
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⟨λ s, match s with | (inl a) := "(inl " ++ repr a ++ ")" | (inr b) := "(inr " ++ repr b ++ ")" end⟩
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instance {α : Type u} {β : Type v} [has_repr α] [has_repr β] : has_repr (α × β) :=
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⟨λ ⟨a, b⟩, "(" ++ repr a ++ ", " ++ repr b ++ ")"⟩
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instance {α : Type u} {β : α → Type v} [has_repr α] [s : ∀ x, has_repr (β x)] : has_repr (sigma β) :=
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⟨λ ⟨a, b⟩, "⟨" ++ repr a ++ ", " ++ repr b ++ "⟩"⟩
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instance {α : Type u} {p : α → Prop} [has_repr α] : has_repr (subtype p) :=
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⟨λ s, repr (val s)⟩
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/- Remark: the code generator replaces this definition with one that display natural numbers in decimal notation -/
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protected def nat.repr : nat → string
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| 0 := "zero"
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| (succ a) := "(succ " ++ nat.repr a ++ ")"
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instance : has_repr nat :=
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⟨nat.repr⟩
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def hex_digit_repr (n : nat) : string :=
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if n ≤ 9 then repr n
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else if n = 10 then "a"
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else if n = 11 then "b"
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else if n = 12 then "c"
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else if n = 13 then "d"
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else if n = 14 then "e"
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else "f"
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def char_to_hex (c : char) : string :=
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let n := char.to_nat c,
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d2 := n / 16,
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d1 := n % 16
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in hex_digit_repr d2 ++ hex_digit_repr d1
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def char.quote_core (c : char) : string :=
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if c = '\n' then "\\n"
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else if c = '\t' then "\\t"
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else if c = '\\' then "\\\\"
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else if c = '\"' then "\\\""
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else if char.to_nat c <= 31 then "\\x" ++ char_to_hex c
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else string.singleton c
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instance : has_repr char :=
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⟨λ c, "'" ++ char.quote_core c ++ "'"⟩
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def string.quote_aux : list char → string
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| [] := ""
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| (x::xs) := char.quote_core x ++ string.quote_aux xs
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def string.quote (s : string) : string :=
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if s.is_empty = tt then "\"\""
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else "\"" ++ string.quote_aux s.to_list ++ "\""
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instance : has_repr string :=
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⟨string.quote⟩
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instance (n : nat) : has_repr (fin n) :=
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⟨λ f, repr (fin.val f)⟩
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instance : has_repr unsigned :=
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⟨λ n, repr (fin.val n)⟩
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def char.repr (c : char) : string :=
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repr c
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