Some structural Under infrastructure

1 files changed, 23 insertions, 8 deletions

diff --git a/src/r.bqn b/src/r.bqn
index 55c10950..5fd2e620 100644
--- a/src/r.bqn
+++ b/src/r.bqn
@@ -163,18 +163,29 @@ SelSub←{
 }
 First ← (0<≠)◶⟨GetFill,0⊸⊑⟩ Deshape
 
+¨ ↩ {𝕨(𝔽⌜)⊘(𝔽_eachd)○ToArray𝕩}
+
 _under_←{
   i←↕l←1×´s←≢𝕩
-  v←𝕨𝔽○𝔾𝕩 ⋄ gi←𝔾s⥊i
-  n←(IsArray gi)⊑{⟨𝕩⟩}‿⥊ ⋄ v↩N v ⋄ gi↩N gi
-  g←Cmp0 _grade_ 0 gi
-  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
+  v←𝕨𝔽○𝔾𝕩 ⋄ root‿elem←𝔾_structural 𝕩
+  Captures←IsArray∘⊣◶⟨1, {𝕨◶0‿𝕩}´⟨IsArray⊢, =○=, 1×´=¨○≢, {1×´⥊𝕨Captures¨𝕩}⟩⟩
+  ! elem Captures v
+  Set←{
+    Set1←𝕨⊸{
+      i←↕l←1×´s←≢𝕩
+      nv‿gi←((IsArray 𝕨)⊑{⟨𝕩⟩}‿⥊)¨ v‿𝕨
+      ! 1×´Nat⌜gi
+      g←Cmp0 _grade_ 0 gi
+      P←(≠g)⊸≤◶⟨(⊑⟜g)⊑gi˙,l⟩
+      e←P j←0
+      s⥊{e=𝕩}◶⟨⊑⟜(⥊𝕩),{𝕩⋄r←(j⊑g)⊑nv⋄e↩P j↩1+j⋄r}⟩⌜i
+    }
+    _at_←{(𝔾{𝕨⊸=⌜𝕩}↕∘≠) 𝔽⍟⊣¨ ⊢}
+    0 { (𝕨≥≠root)◶⟨≢⥊(1+𝕨)⊸𝕊_at_(𝕨⊑root˙)∘⥊, Set1⟩𝕩 } 𝕩
+  }
+  elem (IsArray root)◶⟨v˙_perv elem˙, Set⟩ 𝕩
 }
 
-¨ ↩ {𝕨(𝔽⌜)⊘(𝔽_eachd)○ToArray𝕩}
-
 match←{(0⊑𝕨)◶(1⊑𝕨)‿𝕩}´⟨
   ⟨=○IsArray, 0⟩
   ⟨IsArray∘⊢, =⟩
@@ -701,3 +712,7 @@ FuncInverse ← (⊑ ⊣◶⟨
 ⟩ 1⊸↓) Decompose
 Inverse ← Type◶(3‿1‿2/{⊢⊣𝕩IX∘≡⊢}‿FuncInverse‿("Cannot invert modifier"!0˙))
 ⁼ ↩ {𝕗 (≢∧INF˙⊸≢)◶0‿(5‿_inv_≢0‿¯2⊏Decompose∘⊢)◶⊢‿{𝕏_inv_(𝕎_invChk_𝕏)} Inverse 𝕗}
+
+_structural←{
+  ⟨⟩‿(𝔽⥊⟜(↕1×´⊢)≢𝕩)
+}