Move impl.bqn to src/r.bqn

1 files changed, 0 insertions, 455 deletions

diff --git a/impl.bqn b/impl.bqn
deleted file mode 100644
index 7b873db7..00000000
--- a/impl.bqn
+++ /dev/null
@@ -1,455 +0,0 @@
-◶ ← {𝕨((𝕨𝔽𝕩)⊑𝕘){𝔽}𝕩}     # LIMITED to number left operand result
-⊘ ← {𝕨((1{𝔽}𝕨)-0)◶𝔽‿𝔾 𝕩}
-⊢ ← {𝕩}
-⊣ ← {𝕩}⊘{𝕨}
-˜ ← {𝕩𝔽𝕨⊣𝕩}
-∘ ← {𝔽𝕨𝔾𝕩}
-○ ← {(𝔾𝕨)𝔽𝔾𝕩}
-⊸ ← {(𝔽𝕨⊣𝕩)𝔾𝕩}
-⟜ ← {(𝕨⊣𝕩)𝔽𝔾𝕩}
-⍟ ← {𝕨((𝕨𝔾𝕩)⊑⊢‿𝕗){𝔽}𝕩}   # LIMITED to boolean right operand result
-
-# LIMITED to numeric arguments for scalar cases
-< ← {⟨⟩⥊⟨𝕩⟩} ⊘ (1-≤˜)
-> ←            (1-≤)
-≢ ↩ IsArray◶⟨⟩‿≢  # LIMITED to monadic case
-≠ ← (0<=)◶⟨1⋄0⊑≢⟩
-
-_fold←{
-  ! 1==𝕩
-  l←≠v←𝕩 ⋄ F←𝔽
-  r←𝕨 (0<l)◶{𝕩⋄Identity f}‿{l↩l-1⋄l⊑𝕩}⊘⊣ 𝕩
-  {r↩(𝕩⊑v)F r}⌜(l-1)⊸-⌜↕l
-  r
-}
-´ ← _fold
-
-
-#⌜
-# LAYER 2: Pervasion
-
-ToArray ← <⍟(1-IsArray)
-Int←IsArray◶⟨⌊⊸=,0⟩
-Nat←IsArray◶⟨0⊸≤×⌊⊸=,0⟩
-
-∾ ← {k←≠𝕨⋄k⊸≤◶⟨⊑⟜𝕨⋄-⟜k⊑𝕩˜⟩⌜↕k+≠𝕩}  # LIMITED to two vector arguments
-
-_eachd←{
-  _d←{ # Equal ranks
-    p←≢𝕨
-    ! 1(⊑⟜p=⊑⟜(≢𝕩))⊸×´↕=𝕨
-    p⥊ (⊑⟜(⥊𝕨)𝔽⊑⟜(⥊𝕩))⌜↕1×´p
-  }
-  _e←{ # 𝕨 has smaller or equal rank
-    p←≢𝕨 ⋄ k←=𝕨 ⋄ q←≢𝕩
-    ! 1(⊑⟜p=⊑⟜q)⊸×´↕k
-    l←1(q⊑˜k⊸+)⊸×´↕(=𝕩)-k
-    a←⥊𝕨 ⋄ b←⥊𝕩
-    q⥊⥊(≠a) (⊑⟜a𝔽l⊸×⊸+⊑b˜)⌜○↕ l
-  }
-  =○=◶⟨>○=◶⟨𝔽_e⋄𝔽˜_e˜⟩⋄𝔽_d⟩
-}
-
-_perv←{ # Pervasion
-  R←𝔽{𝕨𝔽_perv𝕩}
-  +○IsArray◶⟨𝔽⋄R⌜⊘(>○IsArray◶{𝕨{𝕗R𝕩}⌜𝕩}‿{𝕩{𝕩R𝕗}⌜𝕨})⋄R _eachd⟩
-}
-
-⌜ ↩ {𝔽⌜○ToArray}
-¨ ↩ {(𝔽⌜)⊘(𝔽_eachd○ToArray)}
-
-match←{(0⊑𝕨)◶(1⊑𝕨)‿𝕩}´⟨
-  ⟨=○IsArray, 0⟩
-  ⟨IsArray∘⊢, =⟩
-  ⟨=○=      , 0⟩
-  ⟨1×´=¨○≢  , 0⟩
-  {1×´⥊𝕨Match¨𝕩}
-⟩
-
-Cmp0 ← ≤˜-≤
-Cmp1 ← (0<1×´≢∘⊢)◶⟨1, IsArray∘⊢◶(1-2×≤)‿{𝕨Cmp1𝕩}⟜(0⊑⥊)⟩
-Cmp ← +○IsArray◶⟨
-  Cmp0
-  IsArray∘⊣◶⟨Cmp1,-Cmp1˜⟩
-  {
-    lc←𝕨CmpLen○≢𝕩
-    cc ← (⊑⟜(⥊𝕨))⊸Cmp⟜(⊑⟜(⥊𝕩)) _getCellCmp´ lc
-    Cc˜0
-  }
-⟩
-_grade←{
-  ! 1≤=𝕩
-  m←1×´1 Cell 𝕩
-  cc←m 𝔽○(⊑⟜(⥊𝕩)) _getCellCmp 0
-  GT←Cc>0˜
-  l←≠𝕩
-  B←l⊸≤◶⊢‿l
-  (↕l){
-    i←-d←𝕨 ⋄ j←ei←ej←0
-    e←3 ⋄ G←GT○(⊑⟜(m⊸ר⍟(1-m=1)𝕩)) ⋄ c←⟨G,0,1,2⟩
-    s←(8≤d)⊑⟨+,{(𝕩-1){𝕩⋄e↩2⋄j↩i⋄i↩𝕩}⍟(1-G)⍟(1-e)𝕩}⟩
-    N←{i↩d+𝕨⋄ej↩B d+ei↩B j↩d+𝕩⋄e↩l≤j⋄S ei⋄i R j}
-    R←{𝕨e◶c𝕩}◶{e+↩2×ei=i↩1+𝕨⋄𝕨}‿{e+↩ej=j↩1+𝕩⋄𝕩}‿N
-    {(i R j)⊑𝕩}⟜𝕩¨𝕩
-  }´(2⋆ni-1+⊢)¨↕ni←-⌊-2 Log l+l=0
-}
-
-Indices←{
-  ! 1==𝕩
-  l←≠𝕩
-  {
-    ! 1×´Nat¨𝕩
-    k←l-1
-    N ← ((⊢+-×0=𝕩⊑˜⊢)`k⊸-⌜↕l)⊑˜k-⊢  # Next nonzero
-    E ← ⊑⟜(+`𝕩)
-    ei←E i←N 0
-    {{ei↩E i↩N𝕩+1⋄i}⍟(𝕩=ei)i}¨↕E k
-  }⍟(0<l)𝕩
-}
-
-_under_←{
-  i←↕l←1×´s←≢𝕩
-  v←⥊𝕨𝔽○𝔾𝕩
-  g←Cmp0 _grade gi←⥊𝔾s⥊i
-  P←(≠g)⊸≤◶⟨(⊑⟜g)⊑gi˜,l⟩
-  e←P j←0
-  s⥊{e=𝕩}◶⟨⊑⟜(⥊𝕩),{𝕩⋄r←(j⊑g)⊑v⋄e↩P j↩1+j⋄r}⟩¨i
-}
-⌾ ← _under_
-
-+ ↩ + _perv
-- ↩ - _perv
-× ↩ (0⊸(<->) ⊘ ×) _perv
-÷ ↩ ÷ _perv
-⋆ ↩ ⋆ _perv
-√ ← ⋆⟜(÷2)   ⊘ (⋆⟜÷˜)
-| ← (×⟜×     ⊘ {𝕩-𝕨×⌊𝕩÷𝕨}) _perv
-⌊ ↩ (⌊       ⊘ {(𝕨>𝕩)⊑𝕨‿𝕩}) _perv
-⌈ ← (-∘⌊∘-   ⊘ {(𝕨<𝕩)⊑𝕨‿𝕩}) _perv
-¬ ← 1+-
-∧ ←            ×
-∨ ←            (+-×)
-< ↩ {⟨⟩⥊⟨𝕩⟩} ⊘ ((1-≤˜) _perv)
-> ↩             (1-≤) _perv
-≠ ↩ ≠        ⊘ ((1-=) _perv)
-= ↩ =        ⊘ (= _perv)
-≥ ← !∘0      ⊘ (≤˜_perv)
-≤ ↩ !∘0      ⊘ (≤ _perv)
-identity ← (0⊑⟨!∘0⟩) {(0⊑𝕨){𝕗=𝕩}◶𝕩‿(1⊑𝕨)}´ ⟨+‿0,-‿0,×‿1,÷‿1,⋆‿1,√‿1,∧‿1,∨‿0,|‿0,⌊‿∞,⌈‿¯∞,<‿0,≤‿1,=‿1,≥‿1,>‿0,≠‿0⟩
-
-SelSub←{
-  ! IsArray 𝕨
-  ! 1×´⥊Int¨ 𝕨
-  l←≠𝕩
-  ! 1×´⥊ ((-l)⊸≤×l⊸>)¨ 𝕨
-  ((⊢+l×0>⊢)¨𝕨)(1==𝕩)◶{
-    c←1×´s←1 Cell 𝕩
-    𝕨((⥊𝕩)⊑˜c⊸×⊸+)⌜s⥊↕c
-  }‿{
-    ⊑⟜𝕩¨𝕨
-  }𝕩
-}
-
-
-#⌜
-# LAYER 3: Remove other limits
-# Now all implementations are full except ∾ and ⊑; ↕ is monadic only
-
-Deshape←IsArray◶{⟨𝕩⟩}‿⥊
-Reshape←{
-  ! 1≥=𝕨
-  𝕨↩Deshape 𝕨
-  ! ∧´Nat¨𝕨
-  l←×´𝕨
-  n←×´≢𝕩
-  𝕨⥊{
-    𝕩(0<n)◶⟨Type⊸(⊣⌜)⋄⥊⊸{⊑⟜𝕨¨n|𝕩}⟩↕l
-  }⍟(l≠n)𝕩
-}⟜ToArray
-⥊ ↩ Deshape        ⊘ Reshape
-
-Range←{
-  I←{!Nat𝕩⋄↕𝕩}
-  M←{!1==𝕩⋄(<⟨⟩)⥊⊸∾⌜´I¨𝕩}
-  IsArray◶I‿M 𝕩
-}
-
-Depth←IsArray◶0‿{1+0⌈´Depth¨⥊𝕩}
-
-≡ ← Depth          ⊘ Match
-≢ ↩ ≢              ⊘ (¬Match)
-
-
-#⌜
-# LAYER 4: Operators
-
-
-DropV← {⊑⟜𝕩¨𝕨+↕𝕨-˜≠𝕩}
-Cell ← DropV⟜≢
-Pair ← {⟨𝕩⟩} ⊘ {⟨𝕨,𝕩⟩}
-
-Merge←{
-  c←≢0⊑⥊𝕩
-  ! ∧´⥊(c≡≢)¨𝕩
-  𝕩⊑⟜⥊˜⌜c⥊↕×´c
-}⍟(0<≠∘⥊)
-> ↩ Merge          ⊘ >
-≍ ← >∘Pair
-_ranks ← {⟨2⟩⊘⟨1,0⟩((⊣-1+|)˜⟜≠⊑¨<∘⊢)⥊∘𝔽}
-_depthOp_←{
-  neg←0>n←𝕨𝔾_ranks𝕩 ⋄ F←𝔽
-  _d←{
-    R←(𝕗+neg)_d
-    𝕨(×⟜2⊸+´2⥊(neg∧𝕗≥0)∨(0⌈𝕗)≥Pair○≡)◶(⟨R¨⋄R⟜𝕩¨∘⊣⋄(𝕨R⊢)¨∘⊢⋄F⟩)𝕩
-  }
-  𝕨 n _d 𝕩
-}
-⚇ ← _depthOp_
-_rankOp_←{
-  k←𝕨(Pair○= (0≤⊢)◶⟨⌊⟜-,0⌈-⟩¨ 𝔾_ranks)𝕩
-  Enc←{
-    f←⊑⟜(≢𝕩)¨↕𝕨
-    c←×´s←𝕨Cell𝕩
-    f⥊⊑⟜(⥊𝕩)¨∘((s⥊↕c)+c×⊢)¨↕×´f
-  }
-  Enc↩(>⟜0+≥⟜=)◶⟨<⊢,Enc,<¨⊢⟩
-  > ((0⊑k)Enc𝕨) 𝔽¨ ((1-˜≠)⊸⊑k)Enc𝕩
-}
-⎉ ← _rankOp_
-˘ ← {𝔽⎉¯1}
-_insert←{
-  ! 1≤=𝕩
-  𝕨 𝔽´ <˘𝕩
-}
-˝ ← _insert
-
-
-#⌜
-# LAYER 5: Structural functions
-
-_onAxes_←{
-  F←𝔽
-  (𝔾<≡)∘⊣◶{ # One axis
-    ! 1≤=𝕩
-    𝕨F𝕩
-  }‿{ # Multiple axes
-    ! 1≥=𝕨
-    ! 𝕨≤○≠≢𝕩
-    l←≠𝕨 ⋄ W←⊑⟜(⥊𝕨)
-    0{(W𝕨)F(1+𝕨)⊸𝕊˘⍟(𝕨<l-1)𝕩}⍟(0<l)𝕩
-  }
-}
-
-Select←ToArray⊸(SelSub _onAxes_ 1)
-⊏ ← 0⊸Select       ⊘ Select
-
-JoinTo←∨○(1≠=)◶∾‿{
-  s←𝕨Pair○≢𝕩
-  a←1⌈´k←≠¨s
-  ! ∧´1≥a-k
-  c←(k¬a)+⟜(↕a-1)⊸⊏¨s
-  ! ≡´c
-  l←+´(a=k)⊣◶1‿(0⊑⊢)¨s
-  (⟨l⟩∾0⊑c)⥊𝕨∾○⥊𝕩
-}
-
-Take←{
-  T←{
-    ! Int 𝕨
-    l←≠𝕩 ⋄ n←𝕨<0 ⋄ e←l⌊r←|𝕨 ⋄ s←⟨r⟩
-    i ← 𝕩{s∾↩c←1 Cell 𝕨⋄𝕩(×+⌜↕∘⊢)×´c}⍟(1≠=𝕩) (l-e)+⍟n ↕e
-    s ⥊ 𝕩{(⥊𝕩)n◶⟨∾,∾˜⟩(r-e)⥊Type𝕗}⍟(l<r) ⊑⟜(⥊𝕩)¨i
-  }
-  𝕨 T _onAxes_ 0 (⟨1⟩⥊˜0⌈𝕨-○≠⊢)⊸∾∘≢⊸⥊𝕩
-}
-Prefixes ← {!1≤=𝕩 ⋄ (↕1+≠𝕩)Take¨<𝕩}
-↑ ← Prefixes       ⊘ Take
-Drop←{
-  s←(≠𝕨)(⊣↑⊢∾˜1⥊˜0⌈-⟜≠)≢𝕩
-  ((sׯ1⋆𝕨>0)+(-s)⌈s⌊𝕨)↑𝕩
-}
-Suffixes ← {!1≤=𝕩 ⋄ (↕1+≠𝕩)Drop¨<𝕩}
-↓ ← Suffixes       ⊘ Drop
-
-Windows←{
-  ! IsArray 𝕩
-  ! 1≥=𝕨
-  ! 𝕨≤○≠≢𝕩
-  ! ∧´Nat¨⥊𝕨
-  s←(≠𝕨)↑≢𝕩
-  ! ∧´𝕨≤1+s
-  𝕨{(∾⟜(𝕨≠⊸↓≢𝕩)∘≢⥊>)<¨⊸⊏⟜𝕩¨s(¬+⌜○Range⊢)⥊𝕨}⍟(0<≠𝕨)𝕩
-}
-
-Reverse ← {!1≤=𝕩 ⋄ (-↕⊸¬≠𝕩)⊏𝕩}
-Rotate ← {!Int𝕨 ⋄ l←≠𝕩⋄(l|𝕨+↕l)⊏𝕩} _onAxes_ 0
-
-Rep ← Indices⊸⊏
-Replicate ← {0<=𝕨}◶(⥊˜⟜≠Rep⊢)‿{!𝕨=○≠𝕩⋄𝕨Rep𝕩} _onAxes_ (1-0=≠)
-
-↕ ↩ Range          ⊘ Windows
-⌽ ← Reverse        ⊘ Rotate
-/ ← Indices        ⊘ Replicate
-
-
-#⌜
-# LAYER 6: Everything else
-
-Join←(1≠=)◶⟨∨´1≠=¨,1⟩◶{
-  # List of lists
-  i←j←¯1⋄e←⟨⟩⋄a←𝕩
-  {{e↩a⊑˜i↩𝕩⋄j↩¯1}⍟(i⊸≠)𝕩⋄(j↩j+1)⊑e}¨/≠¨𝕩
-}‿{
-  # Multidimensional
-  C←(<⟨⟩)⥊⊸∾⌜´⊢  # Cartesian array product
-  ! IsArray 𝕩
-  s←≢¨𝕩
-  d←≠0⊑⥊s
-  ! ∧´⥊d=≠¨s
-  ! d≥=𝕩
-  l←(≢𝕩){(𝕩⊑⟜≢a Pick1˜(j=𝕩)⊸×)¨↕𝕨}¨j←↕r←=a←𝕩
-  ! (r↑¨s)≡C l
-  i←C{p←+´¨↑𝕩⋄(↕0⊑⌽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           ⊘ JoinTo
-⊔ ← Group⟜(↕≠⚇1)   ⊘ Group
-
-Pick1←{
-  ! 1==𝕨
-  ! 𝕨=○≠s←≢𝕩
-  ! ∧´Int¨𝕨
-  ! ∧´𝕨(≥⟜-∧<)s
-  𝕨↩𝕨+s×𝕨<0
-  (⥊𝕩)⊑˜0(⊑⟜𝕨+⊑⟜s×⊢)´-↕⊸¬≠𝕨
-}
-Pickd←(∨´∘⥊IsArray¨∘⊣)◶Pick1‿{Pickd⟜𝕩¨𝕨}
-Pick←IsArray◶⥊‿⊢⊸Pickd
-
-# Searching
-IndexOf←{
-  c←1-˜=𝕨
-  ! 0≤c
-  𝕨 (0<≠𝕨)◶⟨0⎉c∘⊢,(+˝∧`)≢⌜○((0<c)◶⟨⊢,<⎉c⟩)⟩ 𝕩
-}
-UniqueMask←{
-  ! 1≤=𝕩
-  u←0↑𝕩
-  {(≠u)>0⊑⥊u IndexOf 𝕩}◶{u↩u∾𝕩⋄1}‿0˘𝕩
-}
-Find←{
-  r←=𝕨
-  ! r≤=𝕩
-  𝕨 ≡⎉r (≢𝕨) ↕⎉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⊸⊏Pick𝕩˜)¨↕⌊´¨𝕨⊔≢𝕩
-}
-Transpose←(=-1˜)⊸ReorderAxes⍟(0<=)
-⍉ ← Transpose      ⊘ ReorderAxes
-
-# Sorting
-CmpLen ← {
-  e←𝕨-˜○(∨´0⊸=)𝕩
-  𝕨(e=0)◶⟨0,e⟩‿{
-    c←×𝕨-○≠𝕩
-    r←𝕨⌊○≠𝕩
-    l←𝕨{
-      i←+´∧`𝕨=𝕩
-      m←×´⊑⟜𝕨¨↕i
-      {c↩×-´𝕩⋄m↩m×⌊´𝕩}∘(⊑¨⟜𝕨‿𝕩)⍟(r⊸>)i
-      m
-    }○(((-1+↕r)+≠)⊸{⊑⟜𝕩¨𝕨})𝕩
-    ⟨l,c⟩
-  }𝕩
-}
-_getCellCmp ← {
-  Ci←𝔽⋄l←𝕨⋄c←𝕩
-  Cc←{
-    a←𝕨⋄b←𝕩
-    S←(l⊸=)◶{S∘(1+𝕩)⍟(0⊸=)a Ci○(𝕩⊸+)b}‿c
-    S 0
-  }
-  (1≠l)⊑(𝕩⍟(0⊸=)𝔽)‿Cc
-}
-
-_binSearch ← {
-  B ← 𝔽
-  {
-    R←{𝕨{a←B m←𝕩+h←⌊𝕨÷2⋄(h+a×2|𝕨)R a⊑𝕩‿m}⍟(>⟜1)𝕩}
-    1+(𝕩+1)R ¯1
-  }⍟(0⊸<)
-}
-_bins←{
-  c←1-˜=𝕨
-  ! 0≤c
-  ! c≤=𝕩
-  lw←×´sw←1 Cell 𝕨
-  cw←lw 𝔽○(⊑⟜(⥊𝕨)) _getCellCmp 0
-  ! 0⊸<◶⟨1,∧´0≤˜·cw¨⟜(lw⊸+)lw×↕∘-⟜1⟩≠𝕨
-  cx←c-˜=𝕩
-  sx←cx Cell 𝕩 ⋄ lc←sw CmpLen sx
-  cc ← (⊑⟜(⥊𝕨))⊸𝔽⟜(⊑⟜(⥊𝕩)) _getCellCmp´ lc
-  B←(×´sw)⊸×⊸Cc≤0˜
-  (≠𝕨) {B⟜𝕩 _binSearch 𝕨}¨ (×´sx) × ⥊⟜(↕×´)⊑⟜(≢𝕩)¨↕cx
-}
-
-⍋ ←   Cmp _grade   ⊘ (  Cmp _bins)
-⍒ ← -∘Cmp _grade   ⊘ (-∘Cmp _bins)
-∧ ↩ ⍋⊸⊏            ⊘ ∧
-∨ ↩ ⍒⊸⊏            ⊘ ∨
-
-OccurrenceCount ← ⊐˜(⊢-⊏)⍋∘⍋
-ProgressiveIndexOf ← {𝕨⊐○(≍˘⟜OccurrenceCount𝕨⊸⊐)𝕩}
-⊒ ← OccurrenceCount⊘ ProgressiveIndexOf
-
-⊑ ↩ (0⊑⥊)          ⊘ Pick
-◶ ↩ {𝕨((𝕨𝔽𝕩)⊑𝕘){𝔽}𝕩}  # Same definition, new Pick
-
-inverse ← {(⊑(0⊏𝕩)⊐<) ⊑ ((1⊏𝕩)∾⟨!∘0⟩)˜} ⍉ (2∾˜2÷˜≠)⊸⥊ ⟨
-  +, +⊘(-˜)
-  -, -
-  ×, ⊢⊘(÷˜)
-  ÷, ÷
-  ⋆, Log _perv
-  √, ⋆⟜2⊘(⋆˜)
-  ∧, ⊢⊘(÷˜)
-  ∨, ⊢⊘(-˜÷1-⊢)
-  <, {!IsArray𝕩⋄!0==𝕩⋄⊑𝕩}⊘(!∘0)
-  /, {!(⍋≡↕∘≠)𝕩⋄≠¨⊔𝕩}⊘(!∘0)
-⟩
-⁼ ← {Inverse 𝕗}
-
-_repeat_←{
-  n←𝕨𝔾𝕩
-  l←u←0
-  {!Int𝕩⋄l↩l⌊𝕩⋄u↩u⌈𝕩}⚇0 n
-  a←𝕩⋄_p←{𝔽∘⊣`(1+𝕩)⥊<a}
-  pos←(𝕨𝔽 ⊢)_p u
-  neg←(𝕨𝔽⁼⊢)_p-l
-  (|⊑<⟜0⊑pos‿neg˜)⚇0 n
-}
-⍟ ↩ _repeat_