#!/usr/bin/env dbqn

impl ← "◶ ← {𝕨((𝕨𝔽𝕩)⊑𝕘){𝔽}𝕩}
∧ ←            ×
∨ ←            (+-×)


#⌜
# LAYER 2: Pervasion
# After defining _perv, we apply it to all scalar functions,
# making them pervasive. I'm not going to write that out.

ToArray ← IsArray◶<‿⊢

_perv←{ # Pervasion
  (⊢⊘∨○IsArray)◶⟨𝔽⋄𝔽{𝕨𝔽_perv𝕩}¨⟩
}


#⌜
# LAYER 3: Remove other limits
# Now all implementations are full but ↕ is monadic only

Int←IsArray◶⟨⌊⊸=,0⟩
Nat←IsArray◶⟨0⊸≤∧⌊⊸=,0⟩


#⌜
# LAYER 4: Operators


Cell ← ↓⟜≢

_ranks ← {⟨2⟩⊘⟨1,0⟩((⊣-1+|)˜⟜≠⊑¨<∘⊢)⥊∘𝔽}
_depthOp_←{
  neg←0>n←𝕨𝔾_ranks𝕩 ⋄ F←𝔽
  _d←{
    R←(𝕗+neg)_d
    𝕨(2⥊(neg∧𝕗≥0)∨(0⌈𝕗)≥≍○<○≡)◶(⟨R¨⋄R⟜𝕩¨∘⊣⟩≍⟨(𝕨R⊢)¨∘⊢⋄F⟩)𝕩
  }
  𝕨 n _d 𝕩
}
⚇ ← _depthOp_
_rankOp_←{
  k←𝕨(≍○(≠≢) (0≤⊢)◶⟨⌊⟜-,0⌈-⟩¨ 𝔾_ranks)𝕩
  Enc←{
    f←⊑⟜(≢𝕩)¨↕𝕨
    c←1×´s←𝕨Cell𝕩
    f⥊⊑⟜(⥊𝕩)¨∘((s⥊↕c)+c×⊢)¨↕1×´f
  }
  > ((⊑k)Enc𝕨) 𝔽¨ ((1-˜≠)⊸⊑k)Enc𝕩
}
_iterate_←{
  n←𝕨𝔾𝕩
  f←⊑𝕨⟨𝔽⟩⊘⟨𝕨𝔽⊢⟩𝕩
  l←u←0
  {!Int𝕩⋄l↩l⌊𝕩⋄u↩u⌈𝕩}⚇0 n
  a←𝕩⋄_p←{𝔽∘⊣`(1+𝕩)⥊<a}
  pos←F _p u ⋄ neg←F⁼_p-l
  (|⊑<⟜0⊑pos‿neg˜)⚇0 n
}

⎉ ← _rankOp_
⍟ ← _iterate_


#⌜
# LAYER 5: Structural functions

_onAxes_←{
  F←𝔽
  (𝔾<≡)∘⊣◶{ # One axis
    ! 1≤≠≢𝕩
    𝕨F𝕩
  }‿{ # Multiple axes
    ! 1≥≠≢𝕨
    ! 𝕨≤○≠≢𝕩
    R←{(⊑𝕨)F(1↓𝕨)⊸R˘𝕩}⍟{0<≠𝕨}
    𝕨R𝕩
  }
}

Take←{
  T←{
    ! Int 𝕨
    l←≠𝕩
    i←(l+1)|¯1⌈l⌊((𝕨<0)×𝕨+l)+↕|𝕨
    i⊏∾⟜(1⊸Cell⥊Type)⍟(0∨´l=i)𝕩
  }
  𝕨 T _onAxes_ 0 (⟨1⟩⥊˜0⌈𝕨-○≠⊢)⊸∾∘≢⊸⥊𝕩
}
Prefixes ← {!1≤≠≢𝕩 ⋄ (↕1+≠𝕩)Take¨<𝕩}
↑ ← Prefixes       ⊘ Take

Windows←{
  ! IsArray 𝕩
  ! 1≥≠≢𝕨
  ! 𝕨≤○≠≢𝕩
  ! ∧´Nat¨⥊𝕨
  s←(≠𝕨)↑≢𝕩
  ! ∧´𝕨≤1+s
  𝕨{(∾⟜(𝕨≠⊸↓≢𝕩)∘≢⥊>)<¨⊸⊏⟜𝕩¨s(¬+⌜○↕⊢)⥊𝕨}⍟(0<≠𝕨)𝕩
}

Reverse ← {!1≤≠≢𝕩 ⋄ (-↕⊸¬≠𝕩)⊏𝕩}
Rotate ← {!Int𝕨 ⋄ l←≠𝕩⋄(l|𝕨+↕l)⊏𝕩} _onAxes_ 0

Indices←{
  ! 1=≠≢𝕩
  ! ∧´Nat¨𝕩
  ⟨⟩∾´𝕩⥊¨↕≠𝕩
}
Rep ← Indices⊸⊏
Replicate ← {0<≠≢𝕨}◶(⥊˜⟜≠Rep⊢)‿{!𝕨=○≠𝕩⋄𝕨Rep𝕩} _onAxes_ (1-0=≠)

↕ ↩ ↕              ⊘ Windows
⌽ ← Reverse        ⊘ Rotate


#⌜
# LAYER 6: Everything else


Join←{
  C←(<⟨⟩)⥊⊸∾⌜´⊢  # Cartesian array product
  ! IsArray 𝕩
  s←≢¨𝕩
  d←≠⊑s
  ! ∧´⥊d=≠¨s
  ! d≥≠≢𝕩
  l←(≢𝕩){(𝕩⊑⟜≢a⊑˜(j=𝕩)⊸×)¨↕𝕨}¨j←↕r←≠≢a←𝕩
  ! (r↑¨s)≡C l
  i←C{p←+´¨↑𝕩⋄(↕⊑⌽p)-𝕩/¯1↓p}¨l
  >i<¨⊸⊏¨l/𝕩
}⍟(0<≠∘⥊)

Group←{
  ! IsArray 𝕩
  Chk←{!1=≠≢𝕩⋄!∧´Int¨𝕩⋄!∧´¯1≤𝕩⋄≠𝕩}
  l←(1<≡)◶Chk‿{!1=≠≢𝕩⋄Chk¨𝕩}𝕨
  ! l≤○≠≢𝕩
  ! ∧´l=l≠⊸↑≢𝕩
  (𝕨⊸=/𝕩˜)¨↕1+¯1⌈´⚇1𝕨
}

∾ ↩ Join           ⊘ ∾
⊔ ← Group⟜(↕≠⚇1)   ⊘ Group

# Searching
IndexOf←{
  c←1-˜≠≢𝕨
  ! 0≤c
  𝕨 (0<≠𝕨)◶⟨0⎉c∘⊢,((+´<˘)∧`)≢⎉c⎉c‿∞⟩ 𝕩
}
UniqueMask←{
  ! 1≤≠≢𝕩
  u←0↑𝕩
  {(≠u)>⊑u IndexOf 𝕩}◶{u↩u∾𝕩⋄1}‿0˘𝕩
}
Find←{
  r←≠s←≢𝕨
  ! r≤≠≢𝕩
  𝕨 ≡⎉r s ↕⎉r 𝕩
}

⊐ ← !∘0            ⊘ IndexOf
∊ ← UniqueMask     ⊘ (⊐˜<≠∘⊢)
⍷ ← ∊⊸/            ⊘ Find

ReorderAxes←{
  𝕩↩<⍟(0=≡)𝕩
  ! 1≥≠≢𝕨
  𝕨↩⥊𝕨
  ! 𝕨≤○≠≢𝕩
  ! ∧´Nat¨⥊𝕨
  r←(≠≢𝕩)-+´¬∊𝕨
  ! ∧´𝕨<r
  𝕨↩𝕨∾𝕨(¬∘∊˜/⊢)↕r
  (𝕨⊸⊏⊑𝕩˜)¨↕⌊´¨𝕨⊔≢𝕩
}
Transpose←(≠∘≢-1˜)⊸ReorderAxes⍟(0<≠∘≢)
⍉ ← Transpose      ⊘ ReorderAxes

# Sorting
Cmp ← ∨○IsArray◶{ # No arrays
  𝕨(>-<)𝕩 # Assume they're numbers
}‿{ # At least one array
  e←𝕨-˜○(0∨´0=≢)𝕩
  𝕨(e=0)◶e‿{
    c←𝕨×∘-○(IsArray+≠∘≢)𝕩
    s←≢𝕨 ⋄ t←≢𝕩 ⋄ r←s⌊○≠t
    l←s{i←+´∧`𝕨=𝕩⋄m←1×´i↑𝕨⋄{c↩×-´𝕩⋄m↩m×⌊´𝕩}∘(⊑¨⟜𝕨‿𝕩)⍟(r⊸>)i⋄m}○(r↑⌽)t
    a←⥊𝕨⋄b←⥊𝕩
    Trav←(=⟜l)◶{Trav∘(1+𝕩)⍟(0⊸=)a Cmp○(𝕩⊸⊑)b}‿c
    Trav 0
  }𝕩
}

_grade←{
  ! 1≤≠≢𝕩
  i⊐˜+´˘((2⥊≠𝕩)⥊𝔽⎉∞‿¯1⎉¯1‿∞˜𝕩)(⌈⟜0+=⟜0⊸×)>⌜˜i←↕≠𝕩
}
_bins←{
  r←1-˜≠≢𝕨
  ! 0≤r
  LE←0≤𝔽⎉r
  ! (0<≠)◶⟨1,∧´·LE´˘2↕<˘⟩𝕩
  +´𝕨LE⎉¯1‿∞𝕩
}

OccurrenceCount ← ⊐˜(⊢-⊏)⍋∘⍋
ProgressiveIndexOf ← {𝕨⊐○(≍˘⟜OccurrenceCount𝕨⊸⊐)𝕩}

⍋ ←   Cmp _grade   ⊘ (  Cmp _bins)
⍒ ← -∘Cmp _grade   ⊘ (-∘Cmp _bins)
∧ ↩ ⍋⊸⊏            ⊘ ∧
∨ ↩ ⍒⊸⊏            ⊘ ∨
⊒ ← OccurrenceCount⊘ ProgressiveIndexOf
"

X←Raw←{≤4}
{
  chrs←⟨
    "!∧∨∾↑↕⌽⍉⍋⍒⊐⊒∊⍷⊔"
    ""
    "⎉⚇⍟◶"
  ⟩
  nc ← ≠¨chrs
  chr ← ∾chrs
  itr ← 0⥊˜≠chr

  init ← " "⊸∾¨(/⟜"_"¨nc/0‿1‿1)∾¨(nc/"FMD")∾¨(nc+´⊸↑⥊"AB"∾⌜•a)
  post ← ∾⟜" "¨/⟜"_"¨nc/0‿0‿1
  names ← init∾¨(•UCS 48)∾¨post

  Inc  ← {
    i←⊑chr⊐𝕩
    n←0 ⋄ itr↩{n↩1+𝕩}⌾(i⊑⊢)itr
    names↩((i⊑init)∾(•UCS 48+n)∾i⊑post)⌾(i⊑⊢)names
  }

  ⍝ starting built-ins
  inps←⟨"𝕨  ","𝕨,𝕗","𝕨,𝕘"⟩
  ⍎¨names∾¨(nc/("←{⟨"∾∾⟜"⟩ ⋄ ⍎""Using undefined built-in ")¨inps)∾¨∾⟜"""}"¨chr

  ⍝ built-in assumptions
  Mod ← ⍎{𝔽 ((⊑chr⊐𝕨)⊑names) ∾ " ↩ " ∾ 𝕩}

  ⍎"IsArray ← 0≠≡"
  ⍎"Type    ← ⟨⟩⥊0⊸⥊"

  '!' Mod "{𝕩 ⋄ ≤1}⍟¬"
  '↕' Mod "↕"
  '∾' Mod "∾"


  ⍝ checks if line is a builtin redefinition
  E_isdef ← (3≤≠)◶⟨0,∧´⟨chr," ","←↩"⟩∊˜¨3⊸↑⟩

  ⍝ removes comments and replaces built-ins with names
  E_proc ← {
    l←≠chr
    q←≠`𝕩∊"""'" ⋄ f←¬∨`q¬⊸∧𝕩='#'
    ∾ (((l×f/q)+chr⊸⊐) (≥⟜l)◶⟨⊑⟜names,⥊∘⊢⟩¨ ⊢) f/𝕩
  }

  E_redef ← { ⍝ handles [fmd] [←↩]
    tail ← E_proc 3↓𝕩 ⍝ must use old def
    Inc ⊑𝕩
    (E_proc 1↑𝕩) ∾ "←" ∾ tail
  }

  lf ← •UCS 10
  pre ← E_isdef◶E_proc‿E_redef¨ lf((⊢-˜¬×+`)∘=⊔⊢)impl
  Raw↩⍎
  ExecFile←{Raw ∾ ∾⟜lf¨ E_proc¨ •LNS 𝕩}
  X↩Raw∘E_proc
  ⍎ ∾ ∾⟜lf¨ pre
  ≠◶X‿{ExecFile ⊑𝕩}‿{ExecFile ⊑𝕩 ⋄ X 1⊑𝕩} •args
}0