Lookup-based ⁼ implementation

3 files changed, 18 insertions, 2 deletions

diff --git a/dzref_full b/dzref_full
index 3edbb93d..b6e9e517 100755
--- a/dzref_full
+++ b/dzref_full
@@ -35,8 +35,9 @@ X←Raw←{≤4}
     "IsArray ← 0≠≡"
     "_amend  ← {𝕨{𝕩⋄𝕗}⌾(𝕗⊑⊢)𝕩}"
     "Type    ← ⟨⟩⥊0⊸⥊"
+    "Log     ← ⋆⁼"
     '!' Mod "{𝕩 ⋄ ≤1}⍟¬"
-  ⟩∾Mod⟜⥊¨ "+-×÷⋆⌊=≤≢⥊⊑↕⌜⁼"
+  ⟩∾Mod⟜⥊¨ "+-×÷⋆⌊=≤≢⥊⊑↕⌜"
 
 
   # checks if line is a builtin redefinition
diff --git a/impl.bqn b/impl.bqn
index 026c03f3..558ef06b 100644
--- a/impl.bqn
+++ b/impl.bqn
@@ -392,6 +392,20 @@ OccurrenceCount ← ⊐˜(⊢-⊏)⍋∘⍋
 ProgressiveIndexOf ← {𝕨⊐○(≍˘⟜OccurrenceCount𝕨⊸⊐)𝕩}
 ⊒ ← OccurrenceCount⊘ ProgressiveIndexOf
 
+inverse ← {(⊑(0⊏𝕩)⊐<) ⊑ ((1⊏𝕩)∾⟨!∘0⟩)˜} ⍉ (2∾˜2÷˜≠)⊸⥊ ⟨
+  +, +⊘(-˜)
+  -, -
+  ×, ⊢⊘(÷˜)
+  ÷, ÷
+  ⋆, Log
+  √, ⋆⟜2⊘(⋆˜)
+  ∧, ⊢⊘(÷˜)
+  ∨, ⊢⊘(-˜÷1-⊢)
+  <, {!IsArray𝕩⋄!0==𝕩⋄⊑𝕩}⊘(!∘0)
+  /, {!(⍋≡↕∘≠)𝕩⋄≠¨⊔𝕩}⊘(!∘0)
+⟩
+⁼ ← {Inverse 𝕗}
+
 _repeat_←{
   n←𝕨𝔾𝕩
   l←u←0
diff --git a/test/cmpref.bqn b/test/cmpref.bqn
index 8186889a..86788f81 100755
--- a/test/cmpref.bqn
+++ b/test/cmpref.bqn
@@ -32,8 +32,9 @@ pre ← ⟨
   "IsArray ← 0≠≡"
   "_amend  ← {𝕨{𝕩⋄𝕗}⌾(𝕗⊑⊢)𝕩}"
   "Type    ← ⟨⟩⥊0⊸⥊"
+  "Log     ← ⋆⁼"
   '!' Mod "{𝕩 ⋄ ≤1}⍟¬"
-⟩∾Mod⟜⥊¨ "+-×÷⋆⌊=≤≢⥊⊑↕⌜⁼"
+⟩∾Mod⟜⥊¨ "+-×÷⋆⌊=≤≢⥊⊑↕⌜"
 
 
 # checks if line is a builtin redefinition