2 files changed, 18 insertions, 6 deletions
diff --git a/src/pr.bqn b/src/pr.bqn
index f695e4cb..e930e6c6 100755
--- a/src/pr.bqn
+++ b/src/pr.bqn
@@ -24,7 +24,7 @@ Inc ← {
 }
 
 # Required functionality passed in as an argument
-pnam ← ⟨"IsArray", "Type", "Log"⟩∾names⊏˜chr⊐"!+-×÷⋆⌊=≤≢⥊⊑↕⌜`"
+pnam ← ⟨"IsArray","Type","Log","GroupLen","GroupOrd"⟩∾names⊏˜chr⊐"!+-×÷⋆⌊=≤≢⥊⊑↕⌜`"
 
 
 E_isdef ← (3≤≠)◶⟨0,∧´⟨chr," ","←↩"⟩∊˜¨3⊸↑⟩
diff --git a/src/r.bqn b/src/r.bqn
index 21e281ec..9afb02bf 100644
--- a/src/r.bqn
+++ b/src/r.bqn
@@ -299,17 +299,29 @@ Join←(1≠=)◶⟨∨´1≠=⌜,1⟩◶{
   >i<⌜⊸⊏¨l/𝕩
 }⍟(0<≠∘⥊)
 
-Group←{
+_group←{
+  !1==𝕩⋄!∧´Int⌜𝕩⋄!∧´¯1≤𝕩
+  d←(l←GroupLen𝕩)GroupOrd𝕩
+  i←0⋄(𝔽{𝕩⋄(i↩i+1)⊢i⊑d}⌜∘↕)⌜l
+}
+GroupInds←{
+  ! IsArray 𝕩
+  G←⊢_group
+  (1<≡)◶G‿((<<⟨⟩)⥊⊸∾⌜⌜´G⌜)𝕩
+}
+GroupGen←{
   ! IsArray 𝕩
-  Chk←{!1==𝕩⋄!∧´Int⌜𝕩⋄!∧´¯1≤𝕩⋄≠𝕩}
-  l←(1<≡)◶Chk‿{!1==𝕩⋄Chk⌜𝕩}𝕨
+  m←1<≡𝕨
+  l←m◶≠‿{!1==𝕩⋄≠⌜𝕩}𝕨
   ! l≤○≠≢𝕩
   ! ∧´l=l≠⊸↑≢𝕩
-  (𝕨⊸=/𝕩˜)⌜↕1+¯1⌈´⚇1𝕨
+  𝕨m◶(⊏⟜𝕩_group⊣)‿{
+    ⊏⟜(𝕩⥊˜⟨×´l⟩∾(≠l)Cell𝕩)⌜ +⌜⌜´ (⌽×`⟨1⟩∾⌽1↓l) × ⊢_group⌜𝕨
+  }𝕩
 }
 
 ∾ ↩ Join           ⊘ JoinTo
-⊔ ← Group⟜(↕≠⚇1)   ⊘ Group
+⊔ ← GroupInds      ⊘ GroupGen
 
 Pick1←{
   ! 1==𝕨