diff --git a/packages/squiggle-lang/src/rescript/FunctionRegistry.res b/packages/squiggle-lang/src/rescript/FunctionRegistry/FunctionRegistry_Core.res
similarity index 60%
rename from packages/squiggle-lang/src/rescript/FunctionRegistry.res
rename to packages/squiggle-lang/src/rescript/FunctionRegistry/FunctionRegistry_Core.res
index 8f69b3d4..1afd9a66 100644
--- a/packages/squiggle-lang/src/rescript/FunctionRegistry.res
+++ b/packages/squiggle-lang/src/rescript/FunctionRegistry/FunctionRegistry_Core.res
@@ -256,158 +256,3 @@ module Registry = {
     }
   }
 }
-
-let impossibleError = "Wrong inputs / Logically impossible"
-
-module Prepare = {
-  let recordWithTwoArgsToValues = (inputs: array<value>): result<array<value>, string> =>
-    switch inputs {
-    | [Record([(_, n1), (_, n2)])] => Ok([n1, n2])
-    | _ => Error(impossibleError)
-    }
-
-  let twoNumberInputs = (inputs: array<value>): result<(float, float), string> => {
-    switch inputs {
-    | [Number(n1), Number(n2)] => Ok(n1, n2)
-    | _ => Error(impossibleError)
-    }
-  }
-
-  let twoDistOrNumber = (values: array<value>): result<(distOrNumber, distOrNumber), string> => {
-    switch values {
-    | [DistOrNumber(a1), DistOrNumber(a2)] => Ok(a1, a2)
-    | _ => Error(impossibleError)
-    }
-  }
-
-  let twoDistOrNumberFromRecord = (values: array<value>) =>
-    values->recordWithTwoArgsToValues->E.R.bind(twoDistOrNumber)
-}
-
-module Wrappers = {
-  let symbolic = r => DistributionTypes.Symbolic(r)
-  let evDistribution = r => ReducerInterface_ExpressionValue.EvDistribution(r)
-  let symbolicEvDistribution = r => r->Symbolic->evDistribution
-}
-
-module Process = {
-  let twoDistsOrNumbersToDist = (
-    ~fn: ((float, float)) => result<DistributionTypes.genericDist, string>,
-    ~values: (distOrNumber, distOrNumber),
-  ) => {
-    let toSampleSet = r => GenericDist.toSampleSetDist(r, 1000)
-    let sampleSetToExpressionValue = (
-      b: Belt.Result.t<QuriSquiggleLang.SampleSetDist.t, QuriSquiggleLang.DistributionTypes.error>,
-    ) =>
-      switch b {
-      | Ok(r) => Ok(ReducerInterface_ExpressionValue.EvDistribution(SampleSet(r)))
-      | Error(d) => Error(DistributionTypes.Error.toString(d))
-      }
-
-    let mapFnResult = r =>
-      switch r {
-      | Ok(r) => Ok(GenericDist.sample(r))
-      | Error(r) => Error(Operation.Other(r))
-      }
-
-    let singleVarSample = (a, fn) => {
-      let sampleSetResult =
-        toSampleSet(a) |> E.R2.bind(dist =>
-          SampleSetDist.samplesMap(
-            ~fn=f => fn(f)->mapFnResult,
-            dist,
-          )->E.R2.errMap(r => DistributionTypes.SampleSetError(r))
-        )
-      sampleSetResult->sampleSetToExpressionValue
-    }
-
-    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)))
-    | (Dist(a1), Dist(a2)) => {
-        let altFn = (a, b) => fn((a, b))->mapFnResult
-        let sampleSetResult =
-          E.R.merge(toSampleSet(a1), toSampleSet(a2))
-          ->E.R2.errMap(DistributionTypes.Error.toString)
-          ->E.R.bind(((t1, t2)) => {
-            SampleSetDist.map2(~fn=altFn, ~t1, ~t2)->E.R2.errMap(Operation.Error.toString)
-          })
-          ->E.R2.errMap(r => DistributionTypes.OtherError(r))
-        sampleSetResult->sampleSetToExpressionValue
-      }
-    }
-  }
-
-  let twoDistsOrNumbersToDistUsingSymbolicDist = (
-    ~fn: ((float, float)) => result<SymbolicDistTypes.symbolicDist, string>,
-    ~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 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_Record([("mean", mainInputType), ("stdev", mainInputType)])],
-        ~run=inputs =>
-          inputs->Prepare.twoDistOrNumberFromRecord->process(~fn=twoArgs(SymbolicDist.Normal.make)),
-      ),
-      Function.makeDefinition(
-        ~name=fnName,
-        ~inputs=[I_Record([("p5", mainInputType), ("p95", mainInputType)])],
-        ~run=inputs =>
-          inputs
-          ->Prepare.twoDistOrNumberFromRecord
-          ->process(~fn=r => twoArgs(SymbolicDist.Normal.from90PercentCI, r)->Ok),
-      ),
-    ],
-  )
-}
-
-module LognormalFn = {
-  let fnName = "lognormal"
-  let mainInputType = I_DistOrNumber
-
-  let toFn = Function.make(
-    ~name="Lognormal",
-    ~definitions=[
-      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", mainInputType), ("p95", mainInputType)])],
-        ~run=inputs =>
-          inputs
-          ->Prepare.twoDistOrNumberFromRecord
-          ->process(~fn=r => twoArgs(SymbolicDist.Lognormal.from90PercentCI, r)->Ok),
-      ),
-      Function.makeDefinition(
-        ~name=fnName,
-        ~inputs=[I_Record([("mean", mainInputType), ("stdev", mainInputType)])],
-        ~run=inputs =>
-          inputs
-          ->Prepare.twoDistOrNumberFromRecord
-          ->process(~fn=twoArgs(SymbolicDist.Lognormal.fromMeanAndStdev)),
-      ),
-    ],
-  )
-}
-
-let allFunctions = [NormalFn.toFn, LognormalFn.toFn]
diff --git a/packages/squiggle-lang/src/rescript/FunctionRegistry/FunctionRegistry_Helpers.res b/packages/squiggle-lang/src/rescript/FunctionRegistry/FunctionRegistry_Helpers.res
new file mode 100644
index 00000000..487fa811
--- /dev/null
+++ b/packages/squiggle-lang/src/rescript/FunctionRegistry/FunctionRegistry_Helpers.res
@@ -0,0 +1,91 @@
+open FunctionRegistry_Core
+
+let impossibleError = "Wrong inputs / Logically impossible"
+
+module Wrappers = {
+  let symbolic = r => DistributionTypes.Symbolic(r)
+  let evDistribution = r => ReducerInterface_ExpressionValue.EvDistribution(r)
+  let symbolicEvDistribution = r => r->Symbolic->evDistribution
+}
+
+module Prepare = {
+  let recordWithTwoArgsToValues = (inputs: array<value>): result<array<value>, string> =>
+    switch inputs {
+    | [Record([(_, n1), (_, n2)])] => Ok([n1, n2])
+    | _ => Error(impossibleError)
+    }
+
+  let twoNumberInputs = (inputs: array<value>): result<(float, float), string> => {
+    switch inputs {
+    | [Number(n1), Number(n2)] => Ok(n1, n2)
+    | _ => Error(impossibleError)
+    }
+  }
+
+  let twoDistOrNumber = (values: array<value>): result<(distOrNumber, distOrNumber), string> => {
+    switch values {
+    | [DistOrNumber(a1), DistOrNumber(a2)] => Ok(a1, a2)
+    | _ => Error(impossibleError)
+    }
+  }
+
+  let twoDistOrNumberFromRecord = (values: array<value>) =>
+    values->recordWithTwoArgsToValues->E.R.bind(twoDistOrNumber)
+}
+
+module Process = {
+  let twoDistsOrNumbersToDist = (
+    ~fn: ((float, float)) => result<DistributionTypes.genericDist, string>,
+    ~values: (distOrNumber, distOrNumber),
+  ) => {
+    let toSampleSet = r => GenericDist.toSampleSetDist(r, 1000)
+    let sampleSetToExpressionValue = (
+      b: Belt.Result.t<QuriSquiggleLang.SampleSetDist.t, QuriSquiggleLang.DistributionTypes.error>,
+    ) =>
+      switch b {
+      | Ok(r) => Ok(ReducerInterface_ExpressionValue.EvDistribution(SampleSet(r)))
+      | Error(d) => Error(DistributionTypes.Error.toString(d))
+      }
+
+    let mapFnResult = r =>
+      switch r {
+      | Ok(r) => Ok(GenericDist.sample(r))
+      | Error(r) => Error(Operation.Other(r))
+      }
+
+    let singleVarSample = (a, fn) => {
+      let sampleSetResult =
+        toSampleSet(a) |> E.R2.bind(dist =>
+          SampleSetDist.samplesMap(
+            ~fn=f => fn(f)->mapFnResult,
+            dist,
+          )->E.R2.errMap(r => DistributionTypes.SampleSetError(r))
+        )
+      sampleSetResult->sampleSetToExpressionValue
+    }
+
+    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)))
+    | (Dist(a1), Dist(a2)) => {
+        let altFn = (a, b) => fn((a, b))->mapFnResult
+        let sampleSetResult =
+          E.R.merge(toSampleSet(a1), toSampleSet(a2))
+          ->E.R2.errMap(DistributionTypes.Error.toString)
+          ->E.R.bind(((t1, t2)) => {
+            SampleSetDist.map2(~fn=altFn, ~t1, ~t2)->E.R2.errMap(Operation.Error.toString)
+          })
+          ->E.R2.errMap(r => DistributionTypes.OtherError(r))
+        sampleSetResult->sampleSetToExpressionValue
+      }
+    }
+  }
+
+  let twoDistsOrNumbersToDistUsingSymbolicDist = (
+    ~fn: ((float, float)) => result<SymbolicDistTypes.symbolicDist, string>,
+    ~values,
+  ) => {
+    twoDistsOrNumbersToDist(~fn=r => r->fn->E.R2.fmap(Wrappers.symbolic), ~values)
+  }
+}
\ No newline at end of file
diff --git a/packages/squiggle-lang/src/rescript/FunctionRegistry/FunctionRegistry_Library.res b/packages/squiggle-lang/src/rescript/FunctionRegistry/FunctionRegistry_Library.res
new file mode 100644
index 00000000..f0ac6b9a
--- /dev/null
+++ b/packages/squiggle-lang/src/rescript/FunctionRegistry/FunctionRegistry_Library.res
@@ -0,0 +1,67 @@
+open FunctionRegistry_Core
+open FunctionRegistry_Helpers
+
+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 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_Record([("mean", mainInputType), ("stdev", mainInputType)])],
+        ~run=inputs =>
+          inputs->Prepare.twoDistOrNumberFromRecord->process(~fn=twoArgs(SymbolicDist.Normal.make)),
+      ),
+      Function.makeDefinition(
+        ~name=fnName,
+        ~inputs=[I_Record([("p5", mainInputType), ("p95", mainInputType)])],
+        ~run=inputs =>
+          inputs
+          ->Prepare.twoDistOrNumberFromRecord
+          ->process(~fn=r => twoArgs(SymbolicDist.Normal.from90PercentCI, r)->Ok),
+      ),
+    ],
+  )
+}
+
+module LognormalFn = {
+  let fnName = "lognormal"
+  let mainInputType = I_DistOrNumber
+
+  let toFn = Function.make(
+    ~name="Lognormal",
+    ~definitions=[
+      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", mainInputType), ("p95", mainInputType)])],
+        ~run=inputs =>
+          inputs
+          ->Prepare.twoDistOrNumberFromRecord
+          ->process(~fn=r => twoArgs(SymbolicDist.Lognormal.from90PercentCI, r)->Ok),
+      ),
+      Function.makeDefinition(
+        ~name=fnName,
+        ~inputs=[I_Record([("mean", mainInputType), ("stdev", mainInputType)])],
+        ~run=inputs =>
+          inputs
+          ->Prepare.twoDistOrNumberFromRecord
+          ->process(~fn=twoArgs(SymbolicDist.Lognormal.fromMeanAndStdev)),
+      ),
+    ],
+  )
+}
+
+let allFunctions = [NormalFn.toFn, LognormalFn.toFn]
diff --git a/packages/squiggle-lang/src/rescript/ReducerInterface/ReducerInterface_GenericDistribution.res b/packages/squiggle-lang/src/rescript/ReducerInterface/ReducerInterface_GenericDistribution.res
index 2167d9f2..0beb236e 100644
--- a/packages/squiggle-lang/src/rescript/ReducerInterface/ReducerInterface_GenericDistribution.res
+++ b/packages/squiggle-lang/src/rescript/ReducerInterface/ReducerInterface_GenericDistribution.res
@@ -387,13 +387,12 @@ let genericOutputToReducerValue = (o: DistributionOperation.outputType): result<
   | GenDistError(err) => Error(REDistributionError(err))
   }
 
-let registered = FunctionRegistry.allFunctions
+let registered = FunctionRegistry_Library.allFunctions
 
-let tryRegistry = (call: ExpressionValue.functionCall) => {
-  let (fnName, args) = call
-  let response = FunctionRegistry.Registry.matchAndRun(registered, fnName, args)
-  let foo = response->E.O2.fmap(r => r->E.R2.errMap(s => Reducer_ErrorValue.RETodo(s)))
-  foo
+let tryRegistry = ((fnName, args): ExpressionValue.functionCall) => {
+  FunctionRegistry_Core.Registry.matchAndRun(registered, fnName, args)->E.O2.fmap(
+    E.R2.errMap(_, s => Reducer_ErrorValue.RETodo(s)),
+  )
 }
 
 let dispatch = (call: ExpressionValue.functionCall, environment) => {