287 lines
8 KiB
Text
287 lines
8 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.list.basic
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import init.data.char.basic
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import init.data.option.basic
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/- In the VM, strings are implemented using a dynamic array and UTF-8 encoding.
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TODO: mark as opaque -/
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structure string :=
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(data : list char)
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attribute [extern cpp "lean::stringMk"] string.mk
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attribute [extern cpp "lean::stringData"] string.data
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@[extern cpp "lean::stringDecEq"]
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def string.decEq (s₁ s₂ : @& string) : decidable (s₁ = s₂) :=
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match s₁, s₂ with
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| ⟨s₁⟩, ⟨s₂⟩ :=
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if h : s₁ = s₂ then isTrue (congrArg _ h)
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else isFalse (λ h', string.noConfusion h' (λ h', absurd h' h))
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instance : decidableEq string :=
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{decEq := string.decEq}
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def list.asString (s : list char) : string :=
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⟨s⟩
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namespace string
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instance : hasLt string :=
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⟨λ s₁ s₂, s₁.data < s₂.data⟩
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/- Remark: this function has a VM builtin efficient implementation. -/
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@[extern cpp "lean::stringDecLt"]
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instance decLt (s₁ s₂ : @& string) : decidable (s₁ < s₂) :=
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list.hasDecidableLt s₁.data s₂.data
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@[extern cpp "lean::stringLength"]
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def length : (@& string) → nat
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| ⟨s⟩ := s.length
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/- The internal implementation uses dynamic arrays and will perform destructive updates
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if the string is not shared. -/
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@[extern cpp "lean::stringPush"]
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def push : string → char → string
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| ⟨s⟩ c := ⟨s ++ [c]⟩
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/- The internal implementation uses dynamic arrays and will perform destructive updates
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if the string is not shared. -/
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@[extern cpp "lean::stringAppend"]
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def append : string → (@& string) → string
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| ⟨a⟩ ⟨b⟩ := ⟨a ++ b⟩
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/- O(n) in the runtime, where n is the length of the string -/
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def toList (s : string) : list char :=
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s.data
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private def csize (c : char) : usize :=
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usize.ofUint32 c.utf8Size
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private def utf8ByteSizeAux : list char → usize → usize
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| [] r := r
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| (c::cs) r := utf8ByteSizeAux cs (r + csize c)
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@[extern cpp "lean::stringUtf8ByteSize"]
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def utf8ByteSize : (@& string) → usize
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| ⟨s⟩ := utf8ByteSizeAux s 0
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@[inline] def bsize (s : string) : usize :=
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utf8ByteSize s
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abbrev utf8Pos := usize
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def utf8Begin : utf8Pos := 0
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private def utf8GetAux : list char → usize → usize → char
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| [] i p := default char
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| (c::cs) i p := if i = p then c else utf8GetAux cs (i + csize c) p
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@[extern cpp "lean::stringUtf8Get"]
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def utf8Get : (@& string) → utf8Pos → char
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| ⟨s⟩ p := utf8GetAux s 0 p
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private def utf8SetAux (c' : char) : list char → usize → usize → list char
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| [] i p := []
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| (c::cs) i p :=
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if i = p then (c'::cs) else c::(utf8SetAux cs (i + csize c) p)
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@[extern cpp "lean::stringUtf8Set"]
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def utf8Set : string → utf8Pos → char → string
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| ⟨s⟩ i c := ⟨utf8SetAux c s 0 i⟩
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@[extern cpp "lean::stringUtf8Next"]
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def utf8Next (s : @& string) (p : utf8Pos) : utf8Pos :=
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let c := utf8Get s p in
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p + csize c
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private def utf8PrevAux : list char → usize → usize → usize
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| [] i p := 0
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| (c::cs) i p :=
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let cz := csize c in
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let i' := i + cz in
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if i' = p then i else utf8PrevAux cs i' p
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@[extern cpp "lean::stringUtf8Prev"]
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def utf8Prev : (@& string) → utf8Pos → utf8Pos
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| ⟨s⟩ p := if p = 0 then 0 else utf8PrevAux s 0 p
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def front (s : string) : char :=
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utf8Get s 0
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def back (s : string) : char :=
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utf8Get s (utf8Prev s (bsize s))
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@[extern cpp "lean::stringUtf8AtEnd"]
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def utf8AtEnd : (@& string) → utf8Pos → bool
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| s p := p ≥ utf8ByteSize s
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private def utf8ExtractAux₂ : list char → usize → usize → list char
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| [] _ _ := []
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| (c::cs) i e := if i = e then [] else c :: utf8ExtractAux₂ cs (i + csize c) e
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private def utf8ExtractAux₁ : list char → usize → usize → usize → list char
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| [] _ _ _ := []
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| s@(c::cs) i b e := if i = b then utf8ExtractAux₂ s i e else utf8ExtractAux₁ cs (i + csize c) b e
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@[extern cpp "lean::stringUtf8Extract"]
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def extract : (@& string) → utf8Pos → utf8Pos → string
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| ⟨s⟩ b e := if b ≥ e then ⟨[]⟩ else ⟨utf8ExtractAux₁ s 0 b e⟩
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def trimLeftAux (s : string) : nat → utf8Pos → utf8Pos
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| 0 i := i
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| (n+1) i :=
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if i ≥ s.bsize then i
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else let c := s.utf8Get i in
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if !c.isWhitespace then i
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else trimLeftAux n (i + csize c)
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def trimLeft (s : string) : string :=
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let b := trimLeftAux s s.bsize.toNat 0 in
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if b = 0 then s
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else s.extract b s.bsize
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def trimRightAux (s : string) : nat → utf8Pos → utf8Pos
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| 0 i := i
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| (n+1) i :=
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if i = 0 then i
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else
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let i' := s.utf8Prev i in
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let c := s.utf8Get i' in
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if !c.isWhitespace then i
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else trimRightAux n i'
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def trimRight (s : string) : string :=
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let e := trimRightAux s s.bsize.toNat s.bsize in
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if e = s.bsize then s
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else s.extract 0 e
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def trim (s : string) : string :=
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let b := trimLeftAux s s.bsize.toNat 0 in
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let e := trimRightAux s s.bsize.toNat s.bsize in
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if b = 0 && e = s.bsize then s
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else s.extract b e
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structure iterator :=
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(s : string) (offset : nat) (i : usize)
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def mkIterator (s : string) : iterator :=
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⟨s, 0, 0⟩
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namespace iterator
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def remaining : iterator → nat
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| ⟨s, o, _⟩ := s.length - o
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def toString : iterator → string
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| ⟨s, _, _⟩ := s
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def remainingBytes : iterator → usize
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| ⟨s, _, i⟩ := s.bsize - i
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def curr : iterator → char
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| ⟨s, _, i⟩ := utf8Get s i
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def next : iterator → iterator
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| ⟨s, o, i⟩ := ⟨s, o+1, utf8Next s i⟩
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def prev : iterator → iterator
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| ⟨s, o, i⟩ := ⟨s, o-1, utf8Prev s i⟩
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def hasNext : iterator → bool
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| ⟨s, _, i⟩ := i < utf8ByteSize s
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def hasPrev : iterator → bool
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| ⟨s, _, i⟩ := i > 0
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def setCurr : iterator → char → iterator
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| ⟨s, o, i⟩ c := ⟨utf8Set s i c, o, i⟩
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def toEnd : iterator → iterator
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| ⟨s, o, _⟩ := ⟨s, s.length, s.bsize⟩
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def extract : iterator → iterator → string
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| ⟨s₁, _, b⟩ ⟨s₂, _, e⟩ :=
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if s₁ ≠ s₂ || b > e then ""
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else s₁.extract b e
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def forward : iterator → nat → iterator
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| it 0 := it
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| it (n+1) := forward it.next n
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def remainingToString : iterator → string
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| ⟨s, _, i⟩ := s.extract i s.bsize
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/- (isPrefixOfRemaining it₁ it₂) is `tt` iff `it₁.remainingToString` is a prefix
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of `it₂.remainingToString`. -/
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def isPrefixOfRemaining : iterator → iterator → bool
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| ⟨s₁, _, i₁⟩ ⟨s₂, _, i₂⟩ := s₁.extract i₁ s₁.bsize = s₂.extract i₂ (i₂ + (s₁.bsize - i₁))
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end iterator
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end string
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/- The following definitions do not have builtin support in the VM -/
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instance : inhabited string :=
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⟨""⟩
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instance : hasSizeof string :=
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⟨string.length⟩
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instance : hasAppend string :=
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⟨string.append⟩
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namespace string
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def str : string → char → string := push
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def pushn (s : string) (c : char) (n : nat) : string :=
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n.repeat (λ _ s, s.push c) s
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def isEmpty (s : string) : bool :=
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toBool (s.length = 0)
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def join (l : list string) : string :=
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l.foldl (λ r s, r ++ s) ""
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def singleton (c : char) : string :=
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"".push c
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def intercalate (s : string) (ss : list string) : string :=
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(list.intercalate s.toList (ss.map toList)).asString
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namespace iterator
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def nextn : iterator → nat → iterator
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| it 0 := it
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| it (i+1) := nextn it.next i
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def prevn : iterator → nat → iterator
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| it 0 := it
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| it (i+1) := prevn it.prev i
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end iterator
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private def lineColumnAux : nat → string.iterator → nat × nat → nat × nat
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| 0 it r := r
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| (k+1) it r@(line, col) :=
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if it.hasNext = ff then r
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else match it.curr with
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| '\n' := lineColumnAux k it.next (line+1, 0)
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| other := lineColumnAux k it.next (line, col+1)
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def lineColumn (s : string) (offset : nat) : nat × nat :=
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lineColumnAux offset s.mkIterator (1, 0)
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end string
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protected def char.toString (c : char) : string :=
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string.singleton c
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private def toNatCore : string.iterator → nat → nat → nat
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| it 0 r := r
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| it (i+1) r :=
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let c := it.curr in
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let r := r*10 + c.toNat - '0'.toNat in
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toNatCore it.next i r
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def string.toNat (s : string) : nat :=
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toNatCore s.mkIterator s.length 0
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