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/- This file contains various parsing helpers. Started _after_ Day10. -/
import Common.List
import Common.Nat
namespace Parsing
structure MaybeEmptyRectangularGrid (Element : Type) where
width : Nat
height : Nat
elements : Array Element
size_valid : elements.size = width * height
instance : Inhabited (MaybeEmptyRectangularGrid Element) where
default := { width := 0, height := 0, elements := Array.empty, size_valid := rfl}
structure RectangularGrid (Element : Type) extends MaybeEmptyRectangularGrid Element where
not_empty : width > 0 ∧ height > 0
structure RectangularGrid.Coordinate (grid : RectangularGrid Element) where
x : Fin grid.width
y : Fin grid.height
instance {grid : RectangularGrid Element} : BEq grid.Coordinate where
beq := λa b ↦ a.x == b.x && a.y == b.y
instance {grid : RectangularGrid Element} : Hashable grid.Coordinate where
hash := λa ↦ Hashable.hash (a.x, a.y)
instance : ToString (RectangularGrid.Coordinate grid) where
toString := λx ↦ s!"x: {x.x}/{grid.width}, y : {x.y}/{grid.height}"
def RectangularGrid.Coordinate.toIndex {grid : RectangularGrid Element} (coordinate : grid.Coordinate) : Fin (grid.width * grid.height) :=
⟨coordinate.x + grid.width * coordinate.y, Nat.two_d_coordinate_to_index_lt_size coordinate.x.isLt coordinate.y.isLt⟩
def RectangularGrid.Coordinate.ofIndex {grid : RectangularGrid Element} (index : Fin (grid.width * grid.height)) : grid.Coordinate :=
have : grid.width > 0 :=
have := index.isLt
match h : grid.width with
| Nat.zero => absurd ((Nat.zero_mul grid.height).subst (h.subst (motive := λx↦index<x*grid.height) this)) (Nat.not_lt_zero index.val)
| Nat.succ ww => Nat.succ_pos ww
{
x := ⟨index.val % grid.width, Nat.mod_lt index.val this⟩
y := ⟨index.val / grid.width, Nat.div_lt_of_lt_mul index.isLt⟩
}
theorem RectangularGrid.Coordinate.toIndex_inv_fromIndex {grid : RectangularGrid Element} (index : Fin (grid.width * grid.height)) : RectangularGrid.Coordinate.toIndex (RectangularGrid.Coordinate.ofIndex index) = index := by
simp only [RectangularGrid.Coordinate.toIndex, RectangularGrid.Coordinate.ofIndex, Nat.mod_add_div, Fin.eta]
def RectangularGrid.Get {grid : RectangularGrid Element} (coordinate : grid.Coordinate) : Element :=
grid.elements[coordinate.toIndex]'(grid.size_valid.substr coordinate.toIndex.isLt)
instance : GetElem (RectangularGrid Element) (RectangularGrid.Coordinate grid) Element (λg _ ↦ g = grid) where
getElem := λ g c h ↦ g.Get (h▸c)
def RectangularGrid.set {grid : RectangularGrid Element} (coordinate : grid.Coordinate) (value : Element) : RectangularGrid Element :=
let index := (Fin.cast grid.size_valid.symm coordinate.toIndex)
{
grid with
elements := grid.elements.set index value
size_valid := (grid.elements.size_set index value).substr grid.size_valid
}
theorem RectangularGrid.set_same_size {grid : RectangularGrid Element} (coordinate : grid.Coordinate) (value : Element) : (grid.set coordinate value).width = grid.width ∧ (grid.set coordinate value).height = grid.height :=
⟨rfl,rfl⟩
instance [ToString Element] : ToString (MaybeEmptyRectangularGrid Element) where
toString := λe ↦ Id.run do
let mut r := s!"Width: {e.width}, Height: {e.height}"
for h₂ : y in [0:e.height] do
r := r.push '\n'
for h₁ : x in [0:e.width] do
have : x + e.width *y < e.elements.size := by
simp[Membership.mem, inferInstance, Std.instMembershipNatRange] at h₁ h₂
rw[e.size_valid]
exact Nat.two_d_coordinate_to_index_lt_size h₁ h₂
r := r ++ (ToString.toString e.elements[x+e.width*y])
r
instance [ToString Element] : ToString (RectangularGrid Element) where
toString := ToString.toString ∘ RectangularGrid.toMaybeEmptyRectangularGrid
inductive RectangularGrid.ParseError (ParseCharError : Type)
| NoInput : RectangularGrid.ParseError ParseCharError
| NotRectangular : RectangularGrid.ParseError ParseCharError
| CharacterParsingError : ParseCharError → RectangularGrid.ParseError ParseCharError
instance [ToString ParseCharError] : ToString (RectangularGrid.ParseError ParseCharError) where
toString := λ
| .NoInput => "No input provided."
| .NotRectangular => "Input is not rectangular."
| .CharacterParsingError e => ToString.toString e
/-- Internal helper. Not private so it's usable in proofs. You probably want ofSubstring instead. -/
protected def RectangularGrid.parseSingleLine (parseCharacter : Char → Except ParseCharError Element) (alreadyParsed : Array Element) (remainingLine : Substring) : Except (RectangularGrid.ParseError ParseCharError) (Array Element) :=
if _h₁ : remainingLine.isEmpty then
Except.ok alreadyParsed
else
let c := remainingLine.front
match parseCharacter c with
| Except.error e => Except.error $ RectangularGrid.ParseError.CharacterParsingError e
| Except.ok element =>
RectangularGrid.parseSingleLine parseCharacter (alreadyParsed.push element) (remainingLine.drop 1)
termination_by remainingLine.bsize
decreasing_by
simp only [Substring.isEmpty, Substring.bsize, Nat.sub_eq, beq_iff_eq] at _h₁
simp only [Substring.drop, Substring.bsize, Substring.nextn, Substring.next, String.Pos.add_byteIdx, Nat.sub_eq]
split
case isTrue h₂ =>
simp[←(congrArg String.Pos.byteIdx h₂)] at _h₁
case isFalse h₂ =>
simp[String.next, Char.utf8Size]
split <;> try split <;> try split
all_goals omega
/-- Internal helper. Not private so it's usable in proofs. You probably want ofSubstring instead. -/
protected def RectangularGrid.parseLines (parseCharacter : Char → Except ParseCharError Element) (alreadyParsed : MaybeEmptyRectangularGrid Element) (remainingLines : List Substring) : Except (RectangularGrid.ParseError ParseCharError) (RectangularGrid Element) :=
match remainingLines with
| [] =>
if h₁ : alreadyParsed.width = 0 ∨ alreadyParsed.height = 0 then
Except.error RectangularGrid.ParseError.NoInput
else
Except.ok {alreadyParsed with not_empty := ⟨Nat.pos_of_ne_zero (not_or.mp h₁).left, Nat.pos_of_ne_zero (not_or.mp h₁).right⟩}
| l :: ls =>
let currentSize := alreadyParsed.elements.size
match RectangularGrid.parseSingleLine parseCharacter alreadyParsed.elements l with
| Except.error e =>
Except.error e
| Except.ok elements =>
let newSize := elements.size
if alreadyParsed.height = 0 then -- first line
RectangularGrid.parseLines parseCharacter {
width := newSize
height := 1
elements
size_valid := (Nat.mul_one _).substr rfl
} ls
else
if h₂ : newSize = currentSize + alreadyParsed.width then
RectangularGrid.parseLines parseCharacter {
width := alreadyParsed.width
height := alreadyParsed.height + 1
elements
size_valid :=
alreadyParsed.size_valid.subst (motive := λx↦_=x+_) h₂
|> (Nat.mul_succ (alreadyParsed.width) (alreadyParsed.height)).substr
} ls
else
Except.error RectangularGrid.ParseError.NotRectangular
def RectangularGrid.ofSubstring (parseCharacter : Char → Except ParseCharError Element) (input : Substring) : Except (RectangularGrid.ParseError ParseCharError) (RectangularGrid Element) :=
let input := input.trim
let lines := input.splitOn "\n"
let lines := lines.map Substring.trim
let lines := lines.filter $ not ∘ Substring.isEmpty
RectangularGrid.parseLines parseCharacter Inhabited.default lines
def RectangularGrid.ofString (parseCharacter : Char → Except ParseCharError Element) (input : String) : Except (RectangularGrid.ParseError ParseCharError) (RectangularGrid Element) :=
ofSubstring parseCharacter input.toSubstring
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