diff --git a/packages/squiggle-lang/src/rescript/ProgramEvaluator.res b/packages/squiggle-lang/src/rescript/ProgramEvaluator.res
index 6e2b118d..134daec3 100644
--- a/packages/squiggle-lang/src/rescript/ProgramEvaluator.res
+++ b/packages/squiggle-lang/src/rescript/ProgramEvaluator.res
@@ -64,7 +64,7 @@ module Internals = {
   }
   let makeOutputs = (graph, pointSetDist): outputs => {graph: graph, pointSetDist: pointSetDist}
 
-  let makeInputs = (inputs: Inputs.inputs): ASTTypes.AST.samplingInputs => {
+  let makeInputs = (inputs: Inputs.inputs): SamplingInputs.samplingInputs => {
     sampleCount: inputs.samplingInputs.sampleCount |> E.O.default(10000),
     outputXYPoints: inputs.samplingInputs.outputXYPoints |> E.O.default(10000),
     kernelWidth: inputs.samplingInputs.kernelWidth,
@@ -74,7 +74,7 @@ module Internals = {
   let runNode = (inputs, node) =>
     AST.toLeaf(makeInputs(inputs), inputs.environment, node)
 
-  let runProgram = (inputs: Inputs.inputs, p: ASTTypes.Program.program) => {
+  let runProgram = (inputs: Inputs.inputs, p: ASTTypes.AST.program) => {
     let ins = ref(inputs)
     p
     |> E.A.fmap(x =>
diff --git a/packages/squiggle-lang/src/rescript/interpreter/AST.res b/packages/squiggle-lang/src/rescript/interpreter/AST.res
index a7f6619f..4b105f1d 100644
--- a/packages/squiggle-lang/src/rescript/interpreter/AST.res
+++ b/packages/squiggle-lang/src/rescript/interpreter/AST.res
@@ -18,7 +18,7 @@ let toPointSetDist = (samplingInputs, environment, node: node) =>
   | Error(e) => Error(e)
   }
 
-let runFunction = (samplingInputs, environment, inputs, fn: PTypes.Function.t) => {
+let runFunction = (samplingInputs, environment, inputs, fn: ASTTypes.AST.Function.t) => {
   let params = envs(samplingInputs, environment)
-  PTypes.Function.run(params, inputs, fn)
+  ASTTypes.AST.Function.run(params, inputs, fn)
 }
diff --git a/packages/squiggle-lang/src/rescript/interpreter/ASTEvaluator.res b/packages/squiggle-lang/src/rescript/interpreter/ASTEvaluator.res
index 54cee830..481bd382 100644
--- a/packages/squiggle-lang/src/rescript/interpreter/ASTEvaluator.res
+++ b/packages/squiggle-lang/src/rescript/interpreter/ASTEvaluator.res
@@ -1,4 +1,3 @@
-open ASTTypes
 open ASTTypes.AST
 
 type t = node
@@ -44,12 +43,17 @@ module AlgebraicCombination = {
 
   let combine = (evaluationParams, algebraicOp, t1: node, t2: node): result<node, string> =>
     E.R.merge(
-      PTypes.SamplingDistribution.renderIfIsNotSamplingDistribution(evaluationParams, t1),
-      PTypes.SamplingDistribution.renderIfIsNotSamplingDistribution(evaluationParams, t2),
+      ASTTypes.AST.SamplingDistribution.renderIfIsNotSamplingDistribution(evaluationParams, t1),
+      ASTTypes.AST.SamplingDistribution.renderIfIsNotSamplingDistribution(evaluationParams, t2),
     ) |> E.R.bind(_, ((a, b)) =>
       switch choose(a, b) {
       | #Sampling =>
-        PTypes.SamplingDistribution.combineShapesUsingSampling(evaluationParams, algebraicOp, a, b)
+        ASTTypes.AST.SamplingDistribution.combineShapesUsingSampling(
+          evaluationParams,
+          algebraicOp,
+          a,
+          b,
+        )
       | #Analytical => combinationByRendering(evaluationParams, algebraicOp, a, b)
       }
     )
@@ -118,6 +122,12 @@ module PointwiseCombination = {
 }
 
 module Truncate = {
+  type simplificationResult = [
+    | #Solution(ASTTypes.AST.node)
+    | #Error(string)
+    | #NoSolution
+  ]
+
   let trySimplification = (leftCutoff, rightCutoff, t): simplificationResult =>
     switch (leftCutoff, rightCutoff, t) {
     | (None, None, t) => #Solution(t)
@@ -132,7 +142,8 @@ module Truncate = {
     switch // TODO: use named args for xMin/xMax in renderToShape; if we're lucky we can at least get the tail
     // of a distribution we otherwise wouldn't get at all
     Node.ensureIsRendered(evaluationParams, t) {
-    | Ok(#RenderedDist(rs)) => Ok(#RenderedDist(PointSetDist.T.truncate(leftCutoff, rightCutoff, rs)))
+    | Ok(#RenderedDist(rs)) =>
+      Ok(#RenderedDist(PointSetDist.T.truncate(leftCutoff, rightCutoff, rs)))
     | Error(e) => Error(e)
     | _ => Error("Could not truncate distribution.")
     }
@@ -160,7 +171,7 @@ module Normalize = {
     switch t {
     | #RenderedDist(s) => Ok(#RenderedDist(PointSetDist.T.normalize(s)))
     | #SymbolicDist(_) => Ok(t)
-    | _ => evaluateAndRetry(evaluationParams, operationToLeaf, t)
+    | _ => ASTTypes.AST.Node.evaluateAndRetry(evaluationParams, operationToLeaf, t)
     }
 }
 
@@ -170,7 +181,7 @@ module FunctionCall = {
 
   let _runLocalFunction = (name, evaluationParams: evaluationParams, args) =>
     Environment.getFunction(evaluationParams.environment, name) |> E.R.bind(_, ((argNames, fn)) =>
-      PTypes.Function.run(evaluationParams, args, (argNames, fn))
+      ASTTypes.AST.Function.run(evaluationParams, args, (argNames, fn))
     )
 
   let _runWithEvaluatedInputs = (
@@ -195,9 +206,13 @@ module Render = {
     switch t {
     | #Function(_) => Error("Cannot render a function")
     | #SymbolicDist(d) =>
-      Ok(#RenderedDist(SymbolicDist.T.toPointSetDist(evaluationParams.samplingInputs.pointSetDistLength, d)))
+      Ok(
+        #RenderedDist(
+          SymbolicDist.T.toPointSetDist(evaluationParams.samplingInputs.pointSetDistLength, d),
+        ),
+      )
     | #RenderedDist(_) as t => Ok(t) // already a rendered pointSetDist, we're done here
-    | _ => evaluateAndRetry(evaluationParams, operationToLeaf, t)
+    | _ => ASTTypes.AST.Node.evaluateAndRetry(evaluationParams, operationToLeaf, t)
     }
 }
 
@@ -207,10 +222,7 @@ module Render = {
    but most often it will produce a RenderedDist.
    This function is used mainly to turn a parse tree into a single RenderedDist
    that can then be displayed to the user. */
-let rec toLeaf = (
-  evaluationParams: ASTTypes.AST.evaluationParams,
-  node: t,
-): result<t, string> =>
+let rec toLeaf = (evaluationParams: ASTTypes.AST.evaluationParams, node: t): result<t, string> =>
   switch node {
   // Leaf nodes just stay leaf nodes
   | #SymbolicDist(_)
diff --git a/packages/squiggle-lang/src/rescript/interpreter/ASTTypes.res b/packages/squiggle-lang/src/rescript/interpreter/ASTTypes.res
index 85b5ac12..8526e9ec 100644
--- a/packages/squiggle-lang/src/rescript/interpreter/ASTTypes.res
+++ b/packages/squiggle-lang/src/rescript/interpreter/ASTTypes.res
@@ -15,43 +15,20 @@ module AST = {
     | #FunctionCall(string, array<node>)
   ]
 
-  module Hash = {
-    type t<'a> = array<(string, 'a)>
-    let getByName = (t: t<'a>, name) =>
-      E.A.getBy(t, ((n, _)) => n == name) |> E.O.fmap(((_, r)) => r)
-
-    let getByNameResult = (t: t<'a>, name) =>
-      getByName(t, name) |> E.O.toResult(name ++ " expected and not found")
-
-    let getByNames = (hash: t<'a>, names: array<string>) =>
-      names |> E.A.fmap(name => (name, getByName(hash, name)))
-  }
-  // Have nil as option
-
-  type samplingInputs = {
-    sampleCount: int,
-    outputXYPoints: int,
-    kernelWidth: option<float>,
-    pointSetDistLength: int,
-  }
-
-  module SamplingInputs = {
-    type t = {
-      sampleCount: option<int>,
-      outputXYPoints: option<int>,
-      kernelWidth: option<float>,
-      pointSetDistLength: option<int>,
-    }
-    let withDefaults = (t: t): samplingInputs => {
-      sampleCount: t.sampleCount |> E.O.default(10000),
-      outputXYPoints: t.outputXYPoints |> E.O.default(10000),
-      kernelWidth: t.kernelWidth,
-      pointSetDistLength: t.pointSetDistLength |> E.O.default(10000),
-    }
-  }
+  type statement = [
+    | #Assignment(string, node)
+    | #Expression(node)
+  ]
+  type program = array<statement>
 
   type environment = Belt.Map.String.t<node>
 
+  type rec evaluationParams = {
+    samplingInputs: SamplingInputs.samplingInputs,
+    environment: environment,
+    evaluateNode: (evaluationParams, node) => Belt.Result.t<node, string>,
+  }
+
   module Environment = {
     type t = environment
     module MS = Belt.Map.String
@@ -74,18 +51,6 @@ module AST = {
       }
   }
 
-  type rec evaluationParams = {
-    samplingInputs: samplingInputs,
-    environment: environment,
-    evaluateNode: (evaluationParams, node) => Belt.Result.t<node, string>,
-  }
-
-  let evaluateNode = (evaluationParams: evaluationParams) =>
-    evaluationParams.evaluateNode(evaluationParams)
-
-  let evaluateAndRetry = (evaluationParams, fn, node) =>
-    node |> evaluationParams.evaluateNode(evaluationParams) |> E.R.bind(_, fn(evaluationParams))
-
   module Node = {
     let getFloat = (node: node) =>
       node |> (
@@ -97,6 +62,12 @@ module AST = {
           }
       )
 
+    let evaluate = (evaluationParams: evaluationParams) =>
+      evaluationParams.evaluateNode(evaluationParams)
+
+    let evaluateAndRetry = (evaluationParams, fn, node) =>
+      node |> evaluationParams.evaluateNode(evaluationParams) |> E.R.bind(_, fn(evaluationParams))
+
     let rec toString: node => string = x =>
       switch x {
       | #SymbolicDist(d) => SymbolicDist.T.toString(d)
@@ -124,8 +95,7 @@ module AST = {
         "}")
       }
 
-    let render = (evaluationParams: evaluationParams, r) =>
-      #Render(r) |> evaluateNode(evaluationParams)
+    let render = (evaluationParams: evaluationParams, r) => #Render(r) |> evaluate(evaluationParams)
 
     let ensureIsRendered = (params, t) =>
       switch t {
@@ -160,18 +130,143 @@ module AST = {
     let toFloat = (item: node): result<node, string> =>
       item |> toPointSetDist |> E.O.bind(_, _toFloat) |> E.O.toResult("Not valid shape")
   }
-}
 
-type simplificationResult = [
-  | #Solution(AST.node)
-  | #Error(string)
-  | #NoSolution
-]
+  module Function = {
+    type t = (array<string>, node)
+    let fromNode: node => option<t> = node =>
+      switch node {
+      | #Function(r) => Some(r)
+      | _ => None
+      }
+    let argumentNames = ((a, _): t) => a
+    let internals = ((_, b): t) => b
+    let run = (evaluationParams: evaluationParams, args: array<node>, t: t) =>
+      if E.A.length(args) == E.A.length(argumentNames(t)) {
+        let newEnvironment = Belt.Array.zip(argumentNames(t), args) |> Environment.fromArray
+        let newEvaluationParams: evaluationParams = {
+          samplingInputs: evaluationParams.samplingInputs,
+          environment: Environment.mergeKeepSecond(
+            evaluationParams.environment,
+            newEnvironment,
+          ),
+          evaluateNode: evaluationParams.evaluateNode,
+        }
+        evaluationParams.evaluateNode(newEvaluationParams, internals(t))
+      } else {
+        Error("Wrong number of variables")
+      }
+  }
 
-module Program = {
-  type statement = [
-    | #Assignment(string, AST.node)
-    | #Expression(AST.node)
-  ]
-  type program = array<statement>
+  module Primative = {
+    type t = [
+      | #SymbolicDist(SymbolicDistTypes.symbolicDist)
+      | #RenderedDist(PointSetTypes.pointSetDist)
+      | #Function(array<string>, node)
+    ]
+
+    let isPrimative: node => bool = x =>
+      switch x {
+      | #SymbolicDist(_)
+      | #RenderedDist(_)
+      | #Function(_) => true
+      | _ => false
+      }
+
+    let fromNode: node => option<t> = x =>
+      switch x {
+      | #SymbolicDist(_) as n
+      | #RenderedDist(_) as n
+      | #Function(_) as n =>
+        Some(n)
+      | _ => None
+      }
+  }
+
+  module SamplingDistribution = {
+    type t = [
+      | #SymbolicDist(SymbolicDistTypes.symbolicDist)
+      | #RenderedDist(PointSetTypes.pointSetDist)
+    ]
+
+    let isSamplingDistribution: node => bool = x =>
+      switch x {
+      | #SymbolicDist(_) => true
+      | #RenderedDist(_) => true
+      | _ => false
+      }
+
+    let fromNode: node => result<t, string> = x =>
+      switch x {
+      | #SymbolicDist(n) => Ok(#SymbolicDist(n))
+      | #RenderedDist(n) => Ok(#RenderedDist(n))
+      | _ => Error("Not valid type")
+      }
+
+    let renderIfIsNotSamplingDistribution = (params, t): result<node, string> =>
+      !isSamplingDistribution(t)
+        ? switch Node.render(params, t) {
+          | Ok(r) => Ok(r)
+          | Error(e) => Error(e)
+          }
+        : Ok(t)
+
+    let map = (~renderedDistFn, ~symbolicDistFn, node: node) =>
+      node |> (
+        x =>
+          switch x {
+          | #RenderedDist(r) => Some(renderedDistFn(r))
+          | #SymbolicDist(s) => Some(symbolicDistFn(s))
+          | _ => None
+          }
+      )
+
+    let sampleN = n =>
+      map(
+        ~renderedDistFn=PointSetDist.sampleNRendered(n),
+        ~symbolicDistFn=SymbolicDist.T.sampleN(n),
+      )
+
+    let getCombinationSamples = (n, algebraicOp, t1: node, t2: node) =>
+      switch (sampleN(n, t1), sampleN(n, t2)) {
+      | (Some(a), Some(b)) =>
+        Some(
+          Belt.Array.zip(a, b) |> E.A.fmap(((a, b)) => Operation.Algebraic.toFn(algebraicOp, a, b)),
+        )
+      | _ => None
+      }
+
+    let combineShapesUsingSampling = (
+      evaluationParams: evaluationParams,
+      algebraicOp,
+      t1: node,
+      t2: node,
+    ) => {
+      let i1 = renderIfIsNotSamplingDistribution(evaluationParams, t1)
+      let i2 = renderIfIsNotSamplingDistribution(evaluationParams, t2)
+      E.R.merge(i1, i2) |> E.R.bind(_, ((a, b)) => {
+        let samples = getCombinationSamples(
+          evaluationParams.samplingInputs.sampleCount,
+          algebraicOp,
+          a,
+          b,
+        )
+
+        let pointSetDist =
+          samples
+          |> E.O.fmap(r =>
+            SampleSet.toPointSetDist(
+              ~samplingInputs=evaluationParams.samplingInputs,
+              ~samples=r,
+              (),
+            )
+          )
+          |> E.O.bind(_, r => r.pointSetDist)
+          |> E.O.toResult("No response")
+        pointSetDist |> E.R.fmap(r => #Normalize(#RenderedDist(r)))
+      })
+
+      //  todo: This bottom part should probably be somewhere else.
+      // todo: REFACTOR: I'm not sure about the SampleSet line.
+    }
+  }
 }
diff --git a/packages/squiggle-lang/src/rescript/interpreter/PTypes.res b/packages/squiggle-lang/src/rescript/interpreter/PTypes.res
deleted file mode 100644
index bc9ac14a..00000000
--- a/packages/squiggle-lang/src/rescript/interpreter/PTypes.res
+++ /dev/null
@@ -1,138 +0,0 @@
-open ASTTypes.AST
-
-module Function = {
-  type t = (array<string>, node)
-  let fromNode: node => option<t> = node =>
-    switch node {
-    | #Function(r) => Some(r)
-    | _ => None
-    }
-  let argumentNames = ((a, _): t) => a
-  let internals = ((_, b): t) => b
-  let run = (
-    evaluationParams: ASTTypes.AST.evaluationParams,
-    args: array<node>,
-    t: t,
-  ) =>
-    if E.A.length(args) == E.A.length(argumentNames(t)) {
-      let newEnvironment =
-        Belt.Array.zip(
-          argumentNames(t),
-          args,
-        ) |> ASTTypes.AST.Environment.fromArray
-      let newEvaluationParams: ASTTypes.AST.evaluationParams = {
-        samplingInputs: evaluationParams.samplingInputs,
-        environment: ASTTypes.AST.Environment.mergeKeepSecond(
-          evaluationParams.environment,
-          newEnvironment,
-        ),
-        evaluateNode: evaluationParams.evaluateNode,
-      }
-      evaluationParams.evaluateNode(newEvaluationParams, internals(t))
-    } else {
-      Error("Wrong number of variables")
-    }
-}
-
-module Primative = {
-  type t = [
-    | #SymbolicDist(SymbolicDistTypes.symbolicDist)
-    | #RenderedDist(PointSetTypes.pointSetDist)
-    | #Function(array<string>, node)
-  ]
-
-  let isPrimative: node => bool = x =>
-    switch x {
-    | #SymbolicDist(_)
-    | #RenderedDist(_)
-    | #Function(_) => true
-    | _ => false
-    }
-
-  let fromNode: node => option<t> = x =>
-    switch x {
-    | #SymbolicDist(_) as n
-    | #RenderedDist(_) as n
-    | #Function(_) as n =>
-      Some(n)
-    | _ => None
-    }
-}
-
-module SamplingDistribution = {
-  type t = [
-    | #SymbolicDist(SymbolicDistTypes.symbolicDist)
-    | #RenderedDist(PointSetTypes.pointSetDist)
-  ]
-
-  let isSamplingDistribution: node => bool = x =>
-    switch x {
-    | #SymbolicDist(_) => true
-    | #RenderedDist(_) => true
-    | _ => false
-    }
-
-  let fromNode: node => result<t, string> = x =>
-    switch x {
-    | #SymbolicDist(n) => Ok(#SymbolicDist(n))
-    | #RenderedDist(n) => Ok(#RenderedDist(n))
-    | _ => Error("Not valid type")
-    }
-
-  let renderIfIsNotSamplingDistribution = (params, t): result<node, string> =>
-    !isSamplingDistribution(t)
-      ? switch Node.render(params, t) {
-        | Ok(r) => Ok(r)
-        | Error(e) => Error(e)
-        }
-      : Ok(t)
-
-  let map = (~renderedDistFn, ~symbolicDistFn, node: node) =>
-    node |> (
-      x =>
-        switch x {
-        | #RenderedDist(r) => Some(renderedDistFn(r))
-        | #SymbolicDist(s) => Some(symbolicDistFn(s))
-        | _ => None
-        }
-    )
-
-  let sampleN = n =>
-    map(~renderedDistFn=PointSetDist.sampleNRendered(n), ~symbolicDistFn=SymbolicDist.T.sampleN(n))
-
-  let getCombinationSamples = (n, algebraicOp, t1: node, t2: node) =>
-    switch (sampleN(n, t1), sampleN(n, t2)) {
-    | (Some(a), Some(b)) =>
-      Some(
-        Belt.Array.zip(a, b) |> E.A.fmap(((a, b)) => Operation.Algebraic.toFn(algebraicOp, a, b)),
-      )
-    | _ => None
-    }
-
-  let combineShapesUsingSampling = (
-    evaluationParams: evaluationParams,
-    algebraicOp,
-    t1: node,
-    t2: node,
-  ) => {
-    let i1 = renderIfIsNotSamplingDistribution(evaluationParams, t1)
-    let i2 = renderIfIsNotSamplingDistribution(evaluationParams, t2)
-    E.R.merge(i1, i2) |> E.R.bind(_, ((a, b)) => {
-      let samples = getCombinationSamples(
-        evaluationParams.samplingInputs.sampleCount,
-        algebraicOp,
-        a,
-        b,
-      )
-
-      //  todo: This bottom part should probably be somewhere else.
-      // todo: REFACTOR: I'm not sure about the SampleSet line.
-      let pointSetDist =
-        samples
-        |> E.O.fmap(r => SampleSet.toPointSetDist(~samplingInputs=evaluationParams.samplingInputs, ~samples=r, ()))
-        |> E.O.bind(_, r => r.pointSetDist)
-        |> E.O.toResult("No response")
-      pointSetDist |> E.R.fmap(r => #Normalize(#RenderedDist(r)))
-    })
-  }
-}
diff --git a/packages/squiggle-lang/src/rescript/interpreter/typeSystem/HardcodedFunctions.res b/packages/squiggle-lang/src/rescript/interpreter/typeSystem/HardcodedFunctions.res
index 5bf93c4d..2ef80d5d 100644
--- a/packages/squiggle-lang/src/rescript/interpreter/typeSystem/HardcodedFunctions.res
+++ b/packages/squiggle-lang/src/rescript/interpreter/typeSystem/HardcodedFunctions.res
@@ -111,7 +111,7 @@ let verticalScaling = (scaleOp, rs, scaleBy) => {
 }
 
 module Multimodal = {
-  let getByNameResult = ASTTypes.AST.Hash.getByNameResult
+  let getByNameResult = Hash.getByNameResult
 
   let _paramsToDistsAndWeights = (r: array<typedValue>) =>
     switch r {
diff --git a/packages/squiggle-lang/src/rescript/interpreter/typeSystem/TypeSystem.res b/packages/squiggle-lang/src/rescript/interpreter/typeSystem/TypeSystem.res
index 95321dee..16f6e011 100644
--- a/packages/squiggle-lang/src/rescript/interpreter/typeSystem/TypeSystem.res
+++ b/packages/squiggle-lang/src/rescript/interpreter/typeSystem/TypeSystem.res
@@ -73,7 +73,7 @@ module TypedValue = {
       | _ => Error("Type Error: Expected float.")
       }
     | (#SamplingDistribution, _) =>
-      PTypes.SamplingDistribution.renderIfIsNotSamplingDistribution(
+      ASTTypes.AST.SamplingDistribution.renderIfIsNotSamplingDistribution(
         evaluationParams,
         node,
       ) |> E.R.bind(_, fromNode)
@@ -89,7 +89,7 @@ module TypedValue = {
         named |> E.A.fmap(((name, intendedType)) => (
           name,
           intendedType,
-          ASTTypes.AST.Hash.getByName(r, name),
+          Hash.getByName(r, name),
         ))
       let typedHash =
         keyValues
diff --git a/packages/squiggle-lang/src/rescript/parser/Parser.res b/packages/squiggle-lang/src/rescript/parser/Parser.res
index 5f310d19..aebfa1de 100644
--- a/packages/squiggle-lang/src/rescript/parser/Parser.res
+++ b/packages/squiggle-lang/src/rescript/parser/Parser.res
@@ -246,7 +246,7 @@ module MathAdtToDistDst = {
   //   let evaluatedExpression = run(expression);
   //   `Function(_ => Ok(evaluatedExpression));
   // }
-  let rec topLevel = (r): result<ASTTypes.Program.program, string> =>
+  let rec topLevel = (r): result<ASTTypes.AST.program, string> =>
     switch r {
     | FunctionAssignment({name, args, expression}) =>
       switch nodeParser(expression) {
@@ -267,7 +267,7 @@ module MathAdtToDistDst = {
       blocks |> E.A.fmap(b => topLevel(b)) |> E.A.R.firstErrorOrOpen |> E.R.fmap(E.A.concatMany)
     }
 
-  let run = (r): result<ASTTypes.Program.program, string> =>
+  let run = (r): result<ASTTypes.AST.program, string> =>
     r |> MathAdtCleaner.run |> topLevel
 }
 
diff --git a/packages/squiggle-lang/src/rescript/sampleSet/SampleSet.res b/packages/squiggle-lang/src/rescript/sampleSet/SampleSet.res
index 03227ed2..6b20d946 100644
--- a/packages/squiggle-lang/src/rescript/sampleSet/SampleSet.res
+++ b/packages/squiggle-lang/src/rescript/sampleSet/SampleSet.res
@@ -80,7 +80,7 @@ module Internals = {
 
 let toPointSetDist = (
   ~samples: Internals.T.t,
-  ~samplingInputs: ASTTypes.AST.samplingInputs,
+  ~samplingInputs: SamplingInputs.samplingInputs,
   (),
 ) => {
   Array.fast_sort(compare, samples)
diff --git a/packages/squiggle-lang/src/rescript/utility/Hash.res b/packages/squiggle-lang/src/rescript/utility/Hash.res
new file mode 100644
index 00000000..14e78a3f
--- /dev/null
+++ b/packages/squiggle-lang/src/rescript/utility/Hash.res
@@ -0,0 +1,8 @@
+type t<'a> = array<(string, 'a)>
+let getByName = (t: t<'a>, name) => E.A.getBy(t, ((n, _)) => n == name) |> E.O.fmap(((_, r)) => r)
+
+let getByNameResult = (t: t<'a>, name) =>
+  getByName(t, name) |> E.O.toResult(name ++ " expected and not found")
+
+let getByNames = (hash: t<'a>, names: array<string>) =>
+  names |> E.A.fmap(name => (name, getByName(hash, name)))
diff --git a/packages/squiggle-lang/src/rescript/utility/SamplingInputs.res b/packages/squiggle-lang/src/rescript/utility/SamplingInputs.res
new file mode 100644
index 00000000..20ed3cd9
--- /dev/null
+++ b/packages/squiggle-lang/src/rescript/utility/SamplingInputs.res
@@ -0,0 +1,21 @@
+type samplingInputs = {
+  sampleCount: int,
+  outputXYPoints: int,
+  kernelWidth: option<float>,
+  pointSetDistLength: int,
+}
+
+module SamplingInputs = {
+  type t = {
+    sampleCount: option<int>,
+    outputXYPoints: option<int>,
+    kernelWidth: option<float>,
+    pointSetDistLength: option<int>,
+  }
+  let withDefaults = (t: t): samplingInputs => {
+    sampleCount: t.sampleCount |> E.O.default(10000),
+    outputXYPoints: t.outputXYPoints |> E.O.default(10000),
+    kernelWidth: t.kernelWidth,
+    pointSetDistLength: t.pointSetDistLength |> E.O.default(10000),
+  }
+}