diff --git a/packages/squiggle-lang/bsconfig.json b/packages/squiggle-lang/bsconfig.json
index 64f5ffc1..4af37cb2 100644
--- a/packages/squiggle-lang/bsconfig.json
+++ b/packages/squiggle-lang/bsconfig.json
@@ -41,7 +41,7 @@
   },
   "refmt": 3,
   "warnings": {
-    "number": "+A-42-48-9-30-4-102"
+    "number": "+A-42-48-9-30-4-102-20-27-41"
   },
   "ppx-flags": []
 }
diff --git a/packages/squiggle-lang/src/rescript/ReducerInterface/ReducerInterface_ExpressionValue.res b/packages/squiggle-lang/src/rescript/ReducerInterface/ReducerInterface_ExpressionValue.res
index 8c94d752..2ad3a402 100644
--- a/packages/squiggle-lang/src/rescript/ReducerInterface/ReducerInterface_ExpressionValue.res
+++ b/packages/squiggle-lang/src/rescript/ReducerInterface/ReducerInterface_ExpressionValue.res
@@ -12,6 +12,7 @@ type rec expressionValue =
   | EvSymbol(string)
   | EvArray(array<expressionValue>)
   | EvRecord(Js.Dict.t<expressionValue>)
+  | EvDist(GenericDist_Types.genericDist)
 
 type functionCall = (string, array<expressionValue>)
 
@@ -35,6 +36,7 @@ let rec toString = aValue =>
         ->Js.String.concatMany("")
       `{${pairs}}`
     }
+  // | Dist() =>
   }
 
 let toStringWithType = aValue =>
@@ -45,6 +47,7 @@ let toStringWithType = aValue =>
   | EvSymbol(_) => `Symbol::${toString(aValue)}`
   | EvArray(_) => `Array::${toString(aValue)}`
   | EvRecord(_) => `Record::${toString(aValue)}`
+  // | Dist(_) =>
   }
 
 let argsToString = (args: array<expressionValue>): string => {
diff --git a/packages/squiggle-lang/src/rescript/ReducerInterface/ReducerInterface_ExternalLibrary.res b/packages/squiggle-lang/src/rescript/ReducerInterface/ReducerInterface_ExternalLibrary.res
index 4f726650..608c9792 100644
--- a/packages/squiggle-lang/src/rescript/ReducerInterface/ReducerInterface_ExternalLibrary.res
+++ b/packages/squiggle-lang/src/rescript/ReducerInterface/ReducerInterface_ExternalLibrary.res
@@ -13,10 +13,32 @@ module Sample = {
 /*
   Map external calls of Reducer
 */
+let env: GenericDist_GenericOperation.env = {
+  sampleCount: 100,
+  xyPointLength: 100,
+}
+
 let dispatch = (call: ExpressionValue.functionCall, chain): result<expressionValue, 'e> =>
   switch call {
   | ("add", [EvNumber(a), EvNumber(b)]) => Sample.customAdd(a, b)->EvNumber->Ok
-
+  | ("add", [EvDist(a), EvDist(b)]) => {
+    let x = GenericDist_GenericOperation.Output.toDistR(
+      GenericDist_GenericOperation.run(~env, FromDist(ToDistCombination(Algebraic, #Add, #Dist(b)), a))
+    )
+    switch x {
+      | Ok(thing) => Ok(EvDist(thing))
+      | Error(err) => Error(Reducer_ErrorValue.RETodo("")) // TODO:
+    }
+  }
+  | ("add", [EvNumber(a), EvDist(b)]) => {
+    let x = GenericDist_GenericOperation.Output.toDistR(
+      GenericDist_GenericOperation.run(~env, FromDist(ToDistCombination(Algebraic, #Add, #Dist(b)), a))
+    )
+    switch x {
+      | Ok(thing) => Ok(EvDist(thing))
+      | Error(err) => Error(Reducer_ErrorValue.RETodo("")) // TODO:
+    }
+  }
   | call => chain(call)
 
   /*