diff --git a/packages/squiggle-lang/src/rescript/FunctionRegistry.res b/packages/squiggle-lang/src/rescript/FunctionRegistry.res
index 31db2269..10f48f43 100644
--- a/packages/squiggle-lang/src/rescript/FunctionRegistry.res
+++ b/packages/squiggle-lang/src/rescript/FunctionRegistry.res
@@ -92,11 +92,11 @@ module FnDefinition = {
   type definitionMatch = MatchSimple.t
 
   let getArgValues = (f: fnDefinition, args: array<expressionValue>): option<array<value>> => {
-    let inputTypes = f.inputs
+    let mainInputTypes = f.inputs
     if E.A.length(f.inputs) !== E.A.length(args) {
       None
     } else {
-      E.A.zip(inputTypes, args)
+      E.A.zip(mainInputTypes, args)
       ->E.A2.fmap(((input, arg)) => matchInput(input, arg))
       ->E.A.O.openIfAllSome
     }
@@ -273,7 +273,7 @@ module Wrappers = {
 
 module Process = {
   let twoDistsOrNumbersToDist = (
-    ~fn: (float, float) => result<DistributionTypes.genericDist, string>,
+    ~fn: ((float, float)) => result<DistributionTypes.genericDist, string>,
     ~values: (distOrNumber, distOrNumber),
   ) => {
     let toSampleSet = r => GenericDist.toSampleSetDist(r, 1000)
@@ -303,11 +303,11 @@ module Process = {
     }
 
     switch values {
-    | (Number(a1), Number(a2)) => fn(a1, a2)->E.R2.fmap(Wrappers.evDistribution)
-    | (Dist(a1), Number(a2)) => singleVarSample(a1, r => fn(r, a2))
-    | (Number(a1), Dist(a2)) => singleVarSample(a2, r => fn(a1, r))
+    | (Number(a1), Number(a2)) => fn((a1, a2))->E.R2.fmap(Wrappers.evDistribution)
+    | (Dist(a1), Number(a2)) => singleVarSample(a1, r => fn((r, a2)))
+    | (Number(a1), Dist(a2)) => singleVarSample(a2, r => fn((a1, r)))
     | (Dist(a1), Dist(a2)) => {
-        let altFn = (a, b) => fn(a, b)->mapFnResult
+        let altFn = (a, b) => fn((a, b))->mapFnResult
         let sampleSetResult =
           E.R.merge(toSampleSet(a1), toSampleSet(a2))
           ->E.R2.errMap(DistributionTypes.Error.toString)
@@ -321,47 +321,41 @@ module Process = {
   }
 
   let twoDistsOrNumbersToDistUsingSymbolicDist = (
-    ~fn: (float, float) => result<SymbolicDistTypes.symbolicDist, string>,
+    ~fn: ((float, float)) => result<SymbolicDistTypes.symbolicDist, string>,
     ~values,
   ) => {
-    twoDistsOrNumbersToDist(~fn=(a, b) => fn(a, b)->E.R2.fmap(Wrappers.symbolic), ~values)
+    twoDistsOrNumbersToDist(~fn=r => r->fn->E.R2.fmap(Wrappers.symbolic), ~values)
   }
 }
 
+let twoArgs = (fn, (a1, a2)) => fn(a1, a2)
+
+let process = (~fn, r) =>
+  r->E.R.bind(Process.twoDistsOrNumbersToDistUsingSymbolicDist(~fn, ~values=_))
+
 module NormalFn = {
   let fnName = "normal"
-  let twoFloatsToSymoblic = (a1, a2) =>
-    SymbolicDist.Normal.make(a1, a2)
-  let twoFloatsToSymbolic90P = (a1, a2) =>
-    SymbolicDist.Normal.from90PercentCI(a1, a2)->Ok
+  let mainInputType = I_DistOrNumber
 
   let toFn = Function.make(
     ~name="Normal",
     ~definitions=[
+      Function.makeDefinition(~name=fnName, ~inputs=[mainInputType, mainInputType], ~run=inputs => {
+        inputs->Prepare.twoDistOrNumber->process(~fn=twoArgs(SymbolicDist.Normal.make))
+      }),
       Function.makeDefinition(
         ~name=fnName,
-        ~inputs=[I_DistOrNumber, I_DistOrNumber],
-        ~run=inputs => {
-          inputs
-          ->Prepare.twoDistOrNumber
-          ->E.R.bind(Process.twoDistsOrNumbersToDistUsingSymbolicDist(~fn=twoFloatsToSymoblic, ~values=_))
-        },
+        ~inputs=[I_Record([("mean", mainInputType), ("stdev", mainInputType)])],
+        ~run=inputs =>
+          inputs->Prepare.twoDistOrNumberFromRecord->process(~fn=twoArgs(SymbolicDist.Normal.make)),
       ),
       Function.makeDefinition(
         ~name=fnName,
-        ~inputs=[I_Record([("mean", I_DistOrNumber), ("stdev", I_DistOrNumber)])],
+        ~inputs=[I_Record([("p5", mainInputType), ("p95", mainInputType)])],
         ~run=inputs =>
           inputs
           ->Prepare.twoDistOrNumberFromRecord
-          ->E.R.bind(Process.twoDistsOrNumbersToDistUsingSymbolicDist(~fn=twoFloatsToSymoblic, ~values=_)),
-      ),
-      Function.makeDefinition(
-        ~name=fnName,
-        ~inputs=[I_Record([("p5", I_DistOrNumber), ("p95", I_DistOrNumber)])],
-        ~run=inputs =>
-          inputs
-          ->Prepare.twoDistOrNumberFromRecord
-          ->E.R.bind(Process.twoDistsOrNumbersToDistUsingSymbolicDist(~fn=twoFloatsToSymbolic90P, ~values=_)),
+          ->process(~fn=r => twoArgs(SymbolicDist.Normal.from90PercentCI, r)->Ok),
       ),
     ],
   )
@@ -369,36 +363,29 @@ module NormalFn = {
 
 module LognormalFn = {
   let fnName = "lognormal"
-  let twoFloatsToSymoblic = (a1, a2) =>
-    SymbolicDist.Lognormal.make(a1, a2)->E.R2.fmap(Wrappers.symbolic)
-  let twoFloatsToSymbolic90P = (a1, a2) =>
-    SymbolicDist.Lognormal.from90PercentCI(a1, a2)->Wrappers.symbolic->Ok
-  let twoFloatsToMeanStdev = (a1, a2) =>
-    SymbolicDist.Lognormal.fromMeanAndStdev(a1, a2)->E.R2.fmap(Wrappers.symbolic)
+  let mainInputType = I_DistOrNumber
 
   let toFn = Function.make(
     ~name="Lognormal",
     ~definitions=[
-      Function.makeDefinition(~name=fnName, ~inputs=[I_DistOrNumber, I_DistOrNumber], ~run=inputs =>
-        inputs
-        ->Prepare.twoDistOrNumber
-        ->E.R.bind(Process.twoDistsOrNumbersToDist(~fn=twoFloatsToSymoblic, ~values=_))
+      Function.makeDefinition(~name=fnName, ~inputs=[mainInputType, mainInputType], ~run=inputs =>
+        inputs->Prepare.twoDistOrNumber->process(~fn=twoArgs(SymbolicDist.Lognormal.make))
       ),
       Function.makeDefinition(
         ~name=fnName,
-        ~inputs=[I_Record([("p5", I_DistOrNumber), ("p95", I_DistOrNumber)])],
+        ~inputs=[I_Record([("p5", mainInputType), ("p95", mainInputType)])],
         ~run=inputs =>
           inputs
           ->Prepare.twoDistOrNumberFromRecord
-          ->E.R.bind(Process.twoDistsOrNumbersToDist(~fn=twoFloatsToSymbolic90P, ~values=_)),
+          ->process(~fn=r => twoArgs(SymbolicDist.Lognormal.from90PercentCI, r)->Ok),
       ),
       Function.makeDefinition(
         ~name=fnName,
-        ~inputs=[I_Record([("mean", I_DistOrNumber), ("stdev", I_DistOrNumber)])],
+        ~inputs=[I_Record([("mean", mainInputType), ("stdev", mainInputType)])],
         ~run=inputs =>
           inputs
           ->Prepare.twoDistOrNumberFromRecord
-          ->E.R.bind(Process.twoDistsOrNumbersToDist(~fn=twoFloatsToMeanStdev, ~values=_)),
+          ->process(~fn=twoArgs(SymbolicDist.Lognormal.fromMeanAndStdev)),
       ),
     ],
   )