Change NaN operations to results

- Also deleting old GenericDist_Types - Also removing some string errors
2022-04-22 16:27:17 -04:00 · 2022-04-22 16:27:17 -04:00 · 508f673873
commit 508f673873
parent b629759542
28 changed files with 459 additions and 334 deletions
--- a/packages/squiggle-lang/tests/Distributions/DistributionOperation_test.res
+++ b/packages/squiggle-lang/tests/Distributions/DistributionOperation_test.res
@ -30,7 +30,7 @@ let toExt: option<'a> => 'a = E.O.toExt(
 describe("sparkline", () => {
  let runTest = (
    name: string,
-    dist: GenericDist_Types.genericDist,
+    dist: DistributionTypes.genericDist,
    expected: DistributionOperation.outputType,
  ) => {
    test(name, () => {
--- a/packages/squiggle-lang/tests/Distributions/GenericDist_Fixtures.res
+++ b/packages/squiggle-lang/tests/Distributions/GenericDist_Fixtures.res
@ -1,14 +1,14 @@
-let normalDist5: GenericDist_Types.genericDist = Symbolic(#Normal({mean: 5.0, stdev: 2.0}))
-let normalDist10: GenericDist_Types.genericDist = Symbolic(#Normal({mean: 10.0, stdev: 2.0}))
-let normalDist20: GenericDist_Types.genericDist = Symbolic(#Normal({mean: 20.0, stdev: 2.0}))
-let normalDist: GenericDist_Types.genericDist = normalDist5
+let normalDist5: DistributionTypes.genericDist = Symbolic(#Normal({mean: 5.0, stdev: 2.0}))
+let normalDist10: DistributionTypes.genericDist = Symbolic(#Normal({mean: 10.0, stdev: 2.0}))
+let normalDist20: DistributionTypes.genericDist = Symbolic(#Normal({mean: 20.0, stdev: 2.0}))
+let normalDist: DistributionTypes.genericDist = normalDist5

-let betaDist: GenericDist_Types.genericDist = Symbolic(#Beta({alpha: 2.0, beta: 5.0}))
-let lognormalDist: GenericDist_Types.genericDist = Symbolic(#Lognormal({mu: 0.0, sigma: 1.0}))
-let cauchyDist: GenericDist_Types.genericDist = Symbolic(#Cauchy({local: 1.0, scale: 1.0}))
-let triangularDist: GenericDist_Types.genericDist = Symbolic(
+let betaDist: DistributionTypes.genericDist = Symbolic(#Beta({alpha: 2.0, beta: 5.0}))
+let lognormalDist: DistributionTypes.genericDist = Symbolic(#Lognormal({mu: 0.0, sigma: 1.0}))
+let cauchyDist: DistributionTypes.genericDist = Symbolic(#Cauchy({local: 1.0, scale: 1.0}))
+let triangularDist: DistributionTypes.genericDist = Symbolic(
  #Triangular({low: 1.0, medium: 2.0, high: 3.0}),
 )
-let exponentialDist: GenericDist_Types.genericDist = Symbolic(#Exponential({rate: 2.0}))
-let uniformDist: GenericDist_Types.genericDist = Symbolic(#Uniform({low: 9.0, high: 10.0}))
-let floatDist: GenericDist_Types.genericDist = Symbolic(#Float(1e1))
+let exponentialDist: DistributionTypes.genericDist = Symbolic(#Exponential({rate: 2.0}))
+let uniformDist: DistributionTypes.genericDist = Symbolic(#Uniform({low: 9.0, high: 10.0}))
+let floatDist: DistributionTypes.genericDist = Symbolic(#Float(1e1))
--- a/packages/squiggle-lang/tests/Distributions/Invariants/AlgebraicCombination_test.res
+++ b/packages/squiggle-lang/tests/Distributions/Invariants/AlgebraicCombination_test.res
@ -43,7 +43,7 @@ describe("(Algebraic) addition of distributions", () => {
    test("normal(mean=5) + normal(mean=20)", () => {
      normalDist5
      ->algebraicAdd(normalDist20)
-      ->E.R2.fmap(GenericDist_Types.Constructors.UsingDists.mean)
+      ->E.R2.fmap(DistributionTypes.Constructors.UsingDists.mean)
      ->E.R2.fmap(run)
      ->E.R2.fmap(toFloat)
      ->E.R.toExn
@ -57,7 +57,7 @@ describe("(Algebraic) addition of distributions", () => {
      let received =
        uniformDist
        ->algebraicAdd(betaDist)
-        ->E.R2.fmap(GenericDist_Types.Constructors.UsingDists.mean)
+        ->E.R2.fmap(DistributionTypes.Constructors.UsingDists.mean)
        ->E.R2.fmap(run)
        ->E.R2.fmap(toFloat)
        ->E.R.toExn
@ -74,7 +74,7 @@ describe("(Algebraic) addition of distributions", () => {
      let received =
        betaDist
        ->algebraicAdd(uniformDist)
-        ->E.R2.fmap(GenericDist_Types.Constructors.UsingDists.mean)
+        ->E.R2.fmap(DistributionTypes.Constructors.UsingDists.mean)
        ->E.R2.fmap(run)
        ->E.R2.fmap(toFloat)
        ->E.R.toExn
@ -95,7 +95,7 @@ describe("(Algebraic) addition of distributions", () => {
        let received =
          normalDist10 // this should be normal(10, sqrt(8))
          ->Ok
-          ->E.R2.fmap(d => GenericDist_Types.Constructors.UsingDists.pdf(d, x))
+          ->E.R2.fmap(d => DistributionTypes.Constructors.UsingDists.pdf(d, x))
          ->E.R2.fmap(run)
          ->E.R2.fmap(toFloat)
          ->E.R.toOption
@ -103,7 +103,7 @@ describe("(Algebraic) addition of distributions", () => {
        let calculated =
          normalDist5
          ->algebraicAdd(normalDist5)
-          ->E.R2.fmap(d => GenericDist_Types.Constructors.UsingDists.pdf(d, x))
+          ->E.R2.fmap(d => DistributionTypes.Constructors.UsingDists.pdf(d, x))
          ->E.R2.fmap(run)
          ->E.R2.fmap(toFloat)
          ->E.R.toOption
@ -126,7 +126,7 @@ describe("(Algebraic) addition of distributions", () => {
      let received =
        normalDist20
        ->Ok
-        ->E.R2.fmap(d => GenericDist_Types.Constructors.UsingDists.pdf(d, 1.9e1))
+        ->E.R2.fmap(d => DistributionTypes.Constructors.UsingDists.pdf(d, 1.9e1))
        ->E.R2.fmap(run)
        ->E.R2.fmap(toFloat)
        ->E.R.toOption
@ -134,7 +134,7 @@ describe("(Algebraic) addition of distributions", () => {
      let calculated =
        normalDist10
        ->algebraicAdd(normalDist10)
-        ->E.R2.fmap(d => GenericDist_Types.Constructors.UsingDists.pdf(d, 1.9e1))
+        ->E.R2.fmap(d => DistributionTypes.Constructors.UsingDists.pdf(d, 1.9e1))
        ->E.R2.fmap(run)
        ->E.R2.fmap(toFloat)
        ->E.R.toOption
@ -155,7 +155,7 @@ describe("(Algebraic) addition of distributions", () => {
      let received =
        uniformDist
        ->algebraicAdd(betaDist)
-        ->E.R2.fmap(d => GenericDist_Types.Constructors.UsingDists.pdf(d, 1e1))
+        ->E.R2.fmap(d => DistributionTypes.Constructors.UsingDists.pdf(d, 1e1))
        ->E.R2.fmap(run)
        ->E.R2.fmap(toFloat)
        ->E.R.toExn
@ -170,7 +170,7 @@ describe("(Algebraic) addition of distributions", () => {
      let received =
        betaDist
        ->algebraicAdd(uniformDist)
-        ->E.R2.fmap(d => GenericDist_Types.Constructors.UsingDists.pdf(d, 1e1))
+        ->E.R2.fmap(d => DistributionTypes.Constructors.UsingDists.pdf(d, 1e1))
        ->E.R2.fmap(run)
        ->E.R2.fmap(toFloat)
        ->E.R.toExn
@ -187,7 +187,7 @@ describe("(Algebraic) addition of distributions", () => {
      let received =
        normalDist10
        ->Ok
-        ->E.R2.fmap(d => GenericDist_Types.Constructors.UsingDists.cdf(d, x))
+        ->E.R2.fmap(d => DistributionTypes.Constructors.UsingDists.cdf(d, x))
        ->E.R2.fmap(run)
        ->E.R2.fmap(toFloat)
        ->E.R.toOption
@ -195,7 +195,7 @@ describe("(Algebraic) addition of distributions", () => {
      let calculated =
        normalDist5
        ->algebraicAdd(normalDist5)
-        ->E.R2.fmap(d => GenericDist_Types.Constructors.UsingDists.cdf(d, x))
+        ->E.R2.fmap(d => DistributionTypes.Constructors.UsingDists.cdf(d, x))
        ->E.R2.fmap(run)
        ->E.R2.fmap(toFloat)
        ->E.R.toOption
@ -217,7 +217,7 @@ describe("(Algebraic) addition of distributions", () => {
      let received =
        normalDist20
        ->Ok
-        ->E.R2.fmap(d => GenericDist_Types.Constructors.UsingDists.cdf(d, 1.25e1))
+        ->E.R2.fmap(d => DistributionTypes.Constructors.UsingDists.cdf(d, 1.25e1))
        ->E.R2.fmap(run)
        ->E.R2.fmap(toFloat)
        ->E.R.toOption
@ -225,7 +225,7 @@ describe("(Algebraic) addition of distributions", () => {
      let calculated =
        normalDist10
        ->algebraicAdd(normalDist10)
-        ->E.R2.fmap(d => GenericDist_Types.Constructors.UsingDists.cdf(d, 1.25e1))
+        ->E.R2.fmap(d => DistributionTypes.Constructors.UsingDists.cdf(d, 1.25e1))
        ->E.R2.fmap(run)
        ->E.R2.fmap(toFloat)
        ->E.R.toOption
@ -246,7 +246,7 @@ describe("(Algebraic) addition of distributions", () => {
      let received =
        uniformDist
        ->algebraicAdd(betaDist)
-        ->E.R2.fmap(d => GenericDist_Types.Constructors.UsingDists.cdf(d, 1e1))
+        ->E.R2.fmap(d => DistributionTypes.Constructors.UsingDists.cdf(d, 1e1))
        ->E.R2.fmap(run)
        ->E.R2.fmap(toFloat)
        ->E.R.toExn
@ -261,7 +261,7 @@ describe("(Algebraic) addition of distributions", () => {
      let received =
        betaDist
        ->algebraicAdd(uniformDist)
-        ->E.R2.fmap(d => GenericDist_Types.Constructors.UsingDists.cdf(d, 1e1))
+        ->E.R2.fmap(d => DistributionTypes.Constructors.UsingDists.cdf(d, 1e1))
        ->E.R2.fmap(run)
        ->E.R2.fmap(toFloat)
        ->E.R.toExn
@ -279,7 +279,7 @@ describe("(Algebraic) addition of distributions", () => {
      let received =
        normalDist10
        ->Ok
-        ->E.R2.fmap(d => GenericDist_Types.Constructors.UsingDists.inv(d, x))
+        ->E.R2.fmap(d => DistributionTypes.Constructors.UsingDists.inv(d, x))
        ->E.R2.fmap(run)
        ->E.R2.fmap(toFloat)
        ->E.R.toOption
@ -287,7 +287,7 @@ describe("(Algebraic) addition of distributions", () => {
      let calculated =
        normalDist5
        ->algebraicAdd(normalDist5)
-        ->E.R2.fmap(d => GenericDist_Types.Constructors.UsingDists.inv(d, x))
+        ->E.R2.fmap(d => DistributionTypes.Constructors.UsingDists.inv(d, x))
        ->E.R2.fmap(run)
        ->E.R2.fmap(toFloat)
        ->E.R.toOption
@ -309,7 +309,7 @@ describe("(Algebraic) addition of distributions", () => {
      let received =
        normalDist20
        ->Ok
-        ->E.R2.fmap(d => GenericDist_Types.Constructors.UsingDists.inv(d, 1e-1))
+        ->E.R2.fmap(d => DistributionTypes.Constructors.UsingDists.inv(d, 1e-1))
        ->E.R2.fmap(run)
        ->E.R2.fmap(toFloat)
        ->E.R.toOption
@ -317,7 +317,7 @@ describe("(Algebraic) addition of distributions", () => {
      let calculated =
        normalDist10
        ->algebraicAdd(normalDist10)
-        ->E.R2.fmap(d => GenericDist_Types.Constructors.UsingDists.inv(d, 1e-1))
+        ->E.R2.fmap(d => DistributionTypes.Constructors.UsingDists.inv(d, 1e-1))
        ->E.R2.fmap(run)
        ->E.R2.fmap(toFloat)
        ->E.R.toOption
@ -338,7 +338,7 @@ describe("(Algebraic) addition of distributions", () => {
      let received =
        uniformDist
        ->algebraicAdd(betaDist)
-        ->E.R2.fmap(d => GenericDist_Types.Constructors.UsingDists.inv(d, 2e-2))
+        ->E.R2.fmap(d => DistributionTypes.Constructors.UsingDists.inv(d, 2e-2))
        ->E.R2.fmap(run)
        ->E.R2.fmap(toFloat)
        ->E.R.toExn
@ -353,7 +353,7 @@ describe("(Algebraic) addition of distributions", () => {
      let received =
        betaDist
        ->algebraicAdd(uniformDist)
-        ->E.R2.fmap(d => GenericDist_Types.Constructors.UsingDists.inv(d, 2e-2))
+        ->E.R2.fmap(d => DistributionTypes.Constructors.UsingDists.inv(d, 2e-2))
        ->E.R2.fmap(run)
        ->E.R2.fmap(toFloat)
        ->E.R.toExn
--- a/packages/squiggle-lang/tests/Distributions/Invariants/Means_test.res
+++ b/packages/squiggle-lang/tests/Distributions/Invariants/Means_test.res
@ -15,7 +15,7 @@ open TestHelpers
 module Internals = {
  let epsilon = 5e1

-  let mean = GenericDist_Types.Constructors.UsingDists.mean
+  let mean = DistributionTypes.Constructors.UsingDists.mean

  let expectImpossiblePath: string => assertion = algebraicOp =>
    `${algebraicOp} has`->expect->toEqual("failed")
--- a/packages/squiggle-lang/tests/ReducerInterface/ReducerInterface_Distribution_test.res
+++ b/packages/squiggle-lang/tests/ReducerInterface/ReducerInterface_Distribution_test.res
@ -22,7 +22,7 @@ describe("eval on distribution functions", () => {
    testEval("mean(-normal(5,2))", "Ok(-5)")
  })
  describe("to", () => {
-    testEval("5 to 2", "Error(TODO: Low value must be less than high value.)")
+    testEval("5 to 2", "Error(Math Error: Low value must be less than high value.)")
    testEval("to(2,5)", "Ok(Lognormal(1.1512925464970227,0.27853260523016377))")
    testEval("to(-2,2)", "Ok(Normal(0,1.2159136638235384))")
  })
@ -88,8 +88,14 @@ describe("eval on distribution functions", () => {

  describe("log", () => {
    testEval("log(2, uniform(5,8))", "Ok(Sample Set Distribution)")
-    testEval("log(normal(5,2), 3)", "Ok(Sample Set Distribution)")
-    testEval("log(normal(5,2), normal(10,1))", "Ok(Sample Set Distribution)")
+    testEval(
+      "log(normal(5,2), 3)",
+      "Error(Math Error: Operation Error: Operation returned complex result)",
+    )
+    testEval(
+      "log(normal(5,2), normal(10,1))",
+      "Error(Math Error: Operation Error: Operation returned complex result)",
+    )
    testEval("log(uniform(5,8))", "Ok(Sample Set Distribution)")
    testEval("log10(uniform(5,8))", "Ok(Sample Set Distribution)")
  })
--- a/packages/squiggle-lang/tests/TS/Symbolic_test.ts
+++ b/packages/squiggle-lang/tests/TS/Symbolic_test.ts
@ -12,7 +12,7 @@ describe("Symbolic mean", () => {
            expect(squiggleResult.value).toBeCloseTo((x + y + z) / 3);
          } catch (err) {
            expect((err as Error).message).toEqual(
-              "Expected squiggle expression to evaluate but got error: TODO: Triangular values must be increasing order."
+              "Expected squiggle expression to evaluate but got error: Math Error: Triangular values must be increasing order."
            );
          }
        }
--- a/packages/squiggle-lang/src/rescript/Distributions/DistributionOperation/DistributionOperation.res
+++ b/packages/squiggle-lang/src/rescript/Distributions/DistributionOperation/DistributionOperation.res
@ -1,4 +1,4 @@
-type functionCallInfo = GenericDist_Types.Operation.genericFunctionCallInfo
+type functionCallInfo = DistributionTypes.DistributionOperation.genericFunctionCallInfo
 type genericDist = DistributionTypes.genericDist
 type error = DistributionTypes.error

@ -120,7 +120,10 @@ let rec run = (~env, functionCallInfo: functionCallInfo): outputType => {
      (),
    )->OutputLocal.toDistR

-  let fromDistFn = (subFnName: GenericDist_Types.Operation.fromDist, dist: genericDist) => {
+  let fromDistFn = (
+    subFnName: DistributionTypes.DistributionOperation.fromDist,
+    dist: genericDist,
+  ) => {
    let response = switch subFnName {
    | ToFloat(distToFloatOperation) =>
      GenericDist.toFloatOperation(dist, ~toPointSetFn, ~distToFloatOperation)
@ -162,9 +165,9 @@ let rec run = (~env, functionCallInfo: functionCallInfo): outputType => {
      ->GenericDist.pointwiseCombination(~toPointSetFn, ~arithmeticOperation, ~t2)
      ->E.R2.fmap(r => Dist(r))
      ->OutputLocal.fromResult
-    | ToDistCombination(Pointwise, arithmeticOperation, #Float(float)) =>
+    | ToDistCombination(Pointwise, arithmeticOperation, #Float(f)) =>
      dist
-      ->GenericDist.pointwiseCombinationFloat(~toPointSetFn, ~arithmeticOperation, ~float)
+      ->GenericDist.pointwiseCombinationFloat(~toPointSetFn, ~arithmeticOperation, ~f)
      ->E.R2.fmap(r => Dist(r))
      ->OutputLocal.fromResult
    }
@ -192,7 +195,7 @@ module Output = {
  let fmap = (
    ~env,
    input: outputType,
-    functionCallInfo: GenericDist_Types.Operation.singleParamaterFunction,
+    functionCallInfo: DistributionTypes.DistributionOperation.singleParamaterFunction,
  ): outputType => {
    let newFnCall: result<functionCallInfo, error> = switch (functionCallInfo, input) {
    | (FromDist(fromDist), Dist(o)) => Ok(FromDist(fromDist, o))
@ -205,11 +208,11 @@ module Output = {
  }
 }

-// See comment above GenericDist_Types.Constructors to explain the purpose of this module.
+// See comment above DistributionTypes.Constructors to explain the purpose of this module.
 // I tried having another internal module called UsingDists, similar to how its done in
-// GenericDist_Types.Constructors. However, this broke GenType for me, so beware.
+// DistributionTypes.Constructors. However, this broke GenType for me, so beware.
 module Constructors = {
-  module C = GenericDist_Types.Constructors.UsingDists
+  module C = DistributionTypes.Constructors.UsingDists
  open OutputLocal
  let mean = (~env, dist) => C.mean(dist)->run(~env)->toFloatR
  let sample = (~env, dist) => C.sample(dist)->run(~env)->toFloatR
--- a/packages/squiggle-lang/src/rescript/Distributions/DistributionOperation/DistributionOperation.resi
+++ b/packages/squiggle-lang/src/rescript/Distributions/DistributionOperation/DistributionOperation.resi
@ -4,7 +4,7 @@ type env = {
  xyPointLength: int,
 }

-open GenericDist_Types
+open DistributionTypes

@genType
 type outputType =
@ -15,15 +15,15 @@ type outputType =
  | GenDistError(error)

@genType
-let run: (~env: env, GenericDist_Types.Operation.genericFunctionCallInfo) => outputType
+let run: (~env: env, DistributionTypes.DistributionOperation.genericFunctionCallInfo) => outputType
 let runFromDist: (
  ~env: env,
-  ~functionCallInfo: GenericDist_Types.Operation.fromDist,
+  ~functionCallInfo: DistributionTypes.DistributionOperation.fromDist,
  genericDist,
 ) => outputType
 let runFromFloat: (
  ~env: env,
-  ~functionCallInfo: GenericDist_Types.Operation.fromDist,
+  ~functionCallInfo: DistributionTypes.DistributionOperation.fromDist,
  float,
 ) => outputType

@ -38,7 +38,7 @@ module Output: {
  let toBool: t => option<bool>
  let toBoolR: t => result<bool, error>
  let toError: t => option<error>
-  let fmap: (~env: env, t, GenericDist_Types.Operation.singleParamaterFunction) => t
+  let fmap: (~env: env, t, DistributionTypes.DistributionOperation.singleParamaterFunction) => t
 }

 module Constructors: {
--- a/packages/squiggle-lang/src/rescript/Distributions/DistributionTypes.res
+++ b/packages/squiggle-lang/src/rescript/Distributions/DistributionTypes.res
@ -9,9 +9,43 @@ type error =
  | NotYetImplemented
  | Unreachable
  | DistributionVerticalShiftIsInvalid
+  | TooFewSamples
  | ArgumentError(string)
+  | OperationError(Operation.invalidOperationError)
+  | PointSetConversionError(SampleSetDist.pointsetConversionError)
+  | SparklineError(PointSetDist.sparklineError) // This type of error is for when we find a sparkline of a discrete distribution. This should probably at some point be actually implemented
  | Other(string)

+let sampleErrorToDistErr = (err: SampleSetDist.sampleSetError): error =>
+  switch err {
+  | TooFewSamples => TooFewSamples
+  }
+
+@genType
+module Error = {
+  type t = error
+
+  let fromString = (s: string): t => Other(s)
+
+  @genType
+  let toString = (err: error): string =>
+    switch err {
+    | NotYetImplemented => "Function Not Yet Implemented"
+    | Unreachable => "Unreachable"
+    | DistributionVerticalShiftIsInvalid => "Distribution Vertical Shift is Invalid"
+    | ArgumentError(s) => `Argument Error ${s}`
+    | TooFewSamples => "Too Few Samples"
+    | OperationError(err) => `Operation Error: ${Operation.invalidOperationErrorToString(err)}`
+    | PointSetConversionError(err) => SampleSetDist.pointsetConversionErrorToString(err)
+    | SparklineError(err) => PointSetDist.sparklineErrorToString(err)
+    | Other(s) => s
+    }
+
+  let resultStringToResultError: result<'a, string> => result<'a, error> = n =>
+    n->E.R2.errMap(r => r->fromString)
+}
+
+@genType
 module Operation = {
  type direction =
    | Algebraic
@ -43,6 +77,9 @@ module Operation = {
    | #Mean
    | #Sample
  ]
+
+  @genType
+  type pointsetXSelection = [#Linear | #ByWeight]
 }

 module DistributionOperation = {
@ -55,6 +92,12 @@ module DistributionOperation = {

  type toFloatArray = Sample(int)

+  type toBool = IsNormalized
+
+  type toString =
+    | ToString
+    | ToSparkline(int)
+
  type fromDist =
    | ToFloat(Operation.toFloat)
    | ToDist(toDist)
@ -63,7 +106,8 @@ module DistributionOperation = {
        Operation.arithmeticOperation,
        [#Dist(genericDist) | #Float(float)],
      )
-    | ToString
+    | ToString(toString)
+    | ToBool(toBool)

  type singleParamaterFunction =
    | FromDist(fromDist)
@ -86,7 +130,9 @@ module DistributionOperation = {
    | ToDist(ToSampleSet(r)) => `toSampleSet(${E.I.toString(r)})`
    | ToDist(Truncate(_, _)) => `truncate`
    | ToDist(Inspect) => `inspect`
-    | ToString => `toString`
+    | ToString(ToString) => `toString`
+    | ToString(ToSparkline(n)) => `toSparkline(${E.I.toString(n)})`
+    | ToBool(IsNormalized) => `isNormalized`
    | ToDistCombination(Algebraic, _, _) => `algebraic`
    | ToDistCombination(Pointwise, _, _) => `pointwise`
    }
@ -97,3 +143,71 @@ module DistributionOperation = {
    | Mixture(_) => `mixture`
    }
 }
+module Constructors = {
+  type t = DistributionOperation.genericFunctionCallInfo
+
+  module UsingDists = {
+    @genType
+    let mean = (dist): t => FromDist(ToFloat(#Mean), dist)
+    let sample = (dist): t => FromDist(ToFloat(#Sample), dist)
+    let cdf = (dist, x): t => FromDist(ToFloat(#Cdf(x)), dist)
+    let inv = (dist, x): t => FromDist(ToFloat(#Inv(x)), dist)
+    let pdf = (dist, x): t => FromDist(ToFloat(#Pdf(x)), dist)
+    let normalize = (dist): t => FromDist(ToDist(Normalize), dist)
+    let isNormalized = (dist): t => FromDist(ToBool(IsNormalized), dist)
+    let toPointSet = (dist): t => FromDist(ToDist(ToPointSet), dist)
+    let toSampleSet = (dist, r): t => FromDist(ToDist(ToSampleSet(r)), dist)
+    let truncate = (dist, left, right): t => FromDist(ToDist(Truncate(left, right)), dist)
+    let inspect = (dist): t => FromDist(ToDist(Inspect), dist)
+    let toString = (dist): t => FromDist(ToString(ToString), dist)
+    let toSparkline = (dist, n): t => FromDist(ToString(ToSparkline(n)), dist)
+    let algebraicAdd = (dist1, dist2: genericDist): t => FromDist(
+      ToDistCombination(Algebraic, #Add, #Dist(dist2)),
+      dist1,
+    )
+    let algebraicMultiply = (dist1, dist2): t => FromDist(
+      ToDistCombination(Algebraic, #Multiply, #Dist(dist2)),
+      dist1,
+    )
+    let algebraicDivide = (dist1, dist2): t => FromDist(
+      ToDistCombination(Algebraic, #Divide, #Dist(dist2)),
+      dist1,
+    )
+    let algebraicSubtract = (dist1, dist2): t => FromDist(
+      ToDistCombination(Algebraic, #Subtract, #Dist(dist2)),
+      dist1,
+    )
+    let algebraicLogarithm = (dist1, dist2): t => FromDist(
+      ToDistCombination(Algebraic, #Logarithm, #Dist(dist2)),
+      dist1,
+    )
+    let algebraicPower = (dist1, dist2): t => FromDist(
+      ToDistCombination(Algebraic, #Power, #Dist(dist2)),
+      dist1,
+    )
+    let pointwiseAdd = (dist1, dist2): t => FromDist(
+      ToDistCombination(Pointwise, #Add, #Dist(dist2)),
+      dist1,
+    )
+    let pointwiseMultiply = (dist1, dist2): t => FromDist(
+      ToDistCombination(Pointwise, #Multiply, #Dist(dist2)),
+      dist1,
+    )
+    let pointwiseDivide = (dist1, dist2): t => FromDist(
+      ToDistCombination(Pointwise, #Divide, #Dist(dist2)),
+      dist1,
+    )
+    let pointwiseSubtract = (dist1, dist2): t => FromDist(
+      ToDistCombination(Pointwise, #Subtract, #Dist(dist2)),
+      dist1,
+    )
+    let pointwiseLogarithm = (dist1, dist2): t => FromDist(
+      ToDistCombination(Pointwise, #Logarithm, #Dist(dist2)),
+      dist1,
+    )
+    let pointwisePower = (dist1, dist2): t => FromDist(
+      ToDistCombination(Pointwise, #Power, #Dist(dist2)),
+      dist1,
+    )
+  }
+}
--- a/packages/squiggle-lang/src/rescript/Distributions/GenericDist/GenericDist.res
+++ b/packages/squiggle-lang/src/rescript/Distributions/GenericDist/GenericDist.res
@ -14,7 +14,7 @@ let sampleN = (t: t, n) =>
  }

 let toSampleSetDist = (t: t, n) =>
-  SampleSetDist.make(sampleN(t, n))->GenericDist_Types.Error.resultStringToResultError
+  SampleSetDist.make(sampleN(t, n))->E.R2.errMap(DistributionTypes.sampleErrorToDistErr)

 let fromFloat = (f: float): t => Symbolic(SymbolicDist.Float.make(f))

@ -68,7 +68,7 @@ let toPointSet = (
  t,
  ~xyPointLength,
  ~sampleCount,
-  ~xSelection: GenericDist_Types.Operation.pointsetXSelection=#ByWeight,
+  ~xSelection: DistributionTypes.Operation.pointsetXSelection=#ByWeight,
  (),
 ): result<PointSetTypes.pointSetDist, error> => {
  switch (t: t) {
@ -83,7 +83,7 @@ let toPointSet = (
        pointSetDistLength: xyPointLength,
        kernelWidth: None,
      },
-    )->GenericDist_Types.Error.resultStringToResultError
+    )->E.R2.errMap(x => DistributionTypes.PointSetConversionError(x))
  }
 }

@ -97,7 +97,7 @@ let toSparkline = (t: t, ~sampleCount: int, ~bucketCount: int=20, ()): result<st
  t
  ->toPointSet(~xSelection=#Linear, ~xyPointLength=bucketCount * 3, ~sampleCount, ())
  ->E.R.bind(r =>
-    r->PointSetDist.toSparkline(bucketCount)->GenericDist_Types.Error.resultStringToResultError
+    r->PointSetDist.toSparkline(bucketCount)->E.R2.errMap(x => DistributionTypes.SparklineError(x))
  )

 module Truncate = {
@ -148,10 +148,10 @@ let truncate = Truncate.run
 */
 module AlgebraicCombination = {
  let tryAnalyticalSimplification = (
-    arithmeticOperation: GenericDist_Types.Operation.arithmeticOperation,
+    arithmeticOperation: DistributionTypes.Operation.arithmeticOperation,
    t1: t,
    t2: t,
-  ): option<result<SymbolicDistTypes.symbolicDist, string>> =>
+  ): option<result<SymbolicDistTypes.symbolicDist, Operation.invalidOperationError>> =>
    switch (arithmeticOperation, t1, t2) {
    | (arithmeticOperation, Symbolic(d1), Symbolic(d2)) =>
      switch SymbolicDist.T.tryAnalyticalSimplification(d1, d2, arithmeticOperation) {
@ -174,14 +174,14 @@ module AlgebraicCombination = {

  let runMonteCarlo = (
    toSampleSet: toSampleSetFn,
-    arithmeticOperation: GenericDist_Types.Operation.arithmeticOperation,
+    arithmeticOperation: DistributionTypes.Operation.arithmeticOperation,
    t1: t,
    t2: t,
-  ) => {
+  ): result<t, error> => {
    let fn = Operation.Algebraic.toFn(arithmeticOperation)
    E.R.merge(toSampleSet(t1), toSampleSet(t2))
    ->E.R.bind(((t1, t2)) => {
-      SampleSetDist.map2(~fn, ~t1, ~t2)->GenericDist_Types.Error.resultStringToResultError
+      SampleSetDist.map2(~fn, ~t1, ~t2)->E.R2.errMap(x => DistributionTypes.OperationError(x))
    })
    ->E.R2.fmap(r => DistributionTypes.SampleSet(r))
  }
@ -224,7 +224,7 @@ module AlgebraicCombination = {
  ): result<t, error> => {
    switch tryAnalyticalSimplification(arithmeticOperation, t1, t2) {
    | Some(Ok(symbolicDist)) => Ok(Symbolic(symbolicDist))
-    | Some(Error(e)) => Error(Other(e))
+    | Some(Error(e)) => Error(OperationError(e))
    | None =>
      switch chooseConvolutionOrMonteCarlo(arithmeticOperation, t1, t2) {
      | MonteCarlo => runMonteCarlo(toSampleSetFn, arithmeticOperation, t1, t2)
@ -247,7 +247,7 @@ let pointwiseCombination = (
  E.R.merge(toPointSetFn(t1), toPointSetFn(t2))
  ->E.R2.fmap(((t1, t2)) =>
    PointSetDist.combinePointwise(
-      GenericDist_Types.Operation.arithmeticToFn(arithmeticOperation),
+      DistributionTypes.Operation.arithmeticToFn(arithmeticOperation),
      t1,
      t2,
    )
@ -258,23 +258,23 @@ let pointwiseCombination = (
 let pointwiseCombinationFloat = (
  t: t,
  ~toPointSetFn: toPointSetFn,
-  ~arithmeticOperation: GenericDist_Types.Operation.arithmeticOperation,
-  ~float: float,
+  ~arithmeticOperation: DistributionTypes.Operation.arithmeticOperation,
+  ~f: float,
 ): result<t, error> => {
  let m = switch arithmeticOperation {
  | #Add | #Subtract => Error(DistributionTypes.DistributionVerticalShiftIsInvalid)
  | (#Multiply | #Divide | #Power | #Logarithm) as arithmeticOperation =>
-    toPointSetFn(t)->E.R2.fmap(t => {
+    toPointSetFn(t)->E.R.bind(t => {
      //TODO: Move to PointSet codebase
      let fn = (secondary, main) => Operation.Scale.toFn(arithmeticOperation, main, secondary)
      let integralSumCacheFn = Operation.Scale.toIntegralSumCacheFn(arithmeticOperation)
      let integralCacheFn = Operation.Scale.toIntegralCacheFn(arithmeticOperation)
-      PointSetDist.T.mapY(
-        ~integralSumCacheFn=integralSumCacheFn(float),
-        ~integralCacheFn=integralCacheFn(float),
-        ~fn=fn(float),
+      PointSetDist.T.mapYResult(
+        ~integralSumCacheFn=integralSumCacheFn(f),
+        ~integralCacheFn=integralCacheFn(f),
+        ~fn=fn(f),
        t,
-      )
+      )->E.R2.errMap(x => DistributionTypes.OperationError(x))
    })
  }
  m->E.R2.fmap(r => DistributionTypes.PointSet(r))
--- a/packages/squiggle-lang/src/rescript/Distributions/GenericDist/GenericDist.resi
+++ b/packages/squiggle-lang/src/rescript/Distributions/GenericDist/GenericDist.resi
@ -1,5 +1,5 @@
-type t = GenericDist_Types.genericDist
-type error = GenericDist_Types.error
+type t = DistributionTypes.genericDist
+type error = DistributionTypes.error
 type toPointSetFn = t => result<PointSetTypes.pointSetDist, error>
 type toSampleSetFn = t => result<SampleSetDist.t, error>
 type scaleMultiplyFn = (t, float) => result<t, error>
@ -28,7 +28,7 @@ let toPointSet: (
  t,
  ~xyPointLength: int,
  ~sampleCount: int,
-  ~xSelection: GenericDist_Types.Operation.pointsetXSelection=?,
+  ~xSelection: DistributionTypes.Operation.pointsetXSelection=?,
  unit,
 ) => result<PointSetTypes.pointSetDist, error>
 let toSparkline: (t, ~sampleCount: int, ~bucketCount: int=?, unit) => result<string, error>
@ -45,22 +45,22 @@ let algebraicCombination: (
  t,
  ~toPointSetFn: toPointSetFn,
  ~toSampleSetFn: toSampleSetFn,
-  ~arithmeticOperation: GenericDist_Types.Operation.arithmeticOperation,
+  ~arithmeticOperation: DistributionTypes.Operation.arithmeticOperation,
  ~t2: t,
 ) => result<t, error>

 let pointwiseCombination: (
  t,
  ~toPointSetFn: toPointSetFn,
-  ~arithmeticOperation: GenericDist_Types.Operation.arithmeticOperation,
+  ~arithmeticOperation: DistributionTypes.Operation.arithmeticOperation,
  ~t2: t,
 ) => result<t, error>

 let pointwiseCombinationFloat: (
  t,
  ~toPointSetFn: toPointSetFn,
-  ~arithmeticOperation: GenericDist_Types.Operation.arithmeticOperation,
-  ~float: float,
+  ~arithmeticOperation: DistributionTypes.Operation.arithmeticOperation,
+  ~f: float,
 ) => result<t, error>

 let mixture: (
--- a/packages/squiggle-lang/src/rescript/Distributions/GenericDist/GenericDist_Types.res
+++ b/packages/squiggle-lang/src/rescript/Distributions/GenericDist/GenericDist_Types.res
@ -1,194 +0,0 @@
-type genericDist = DistributionTypes.genericDist
-@genType
-type error = DistributionTypes.error
-
-@genType
-module Error = {
-  type t = error
-
-  let fromString = (s: string): t => Other(s)
-
-  @genType
-  let toString = (x: t) => {
-    switch x {
-    | NotYetImplemented => "Not Yet Implemented"
-    | Unreachable => "Unreachable"
-    | DistributionVerticalShiftIsInvalid => "Distribution Vertical Shift Is Invalid"
-    | ArgumentError(x) => `Argument Error: ${x}`
-    | Other(s) => s
-    }
-  }
-
-  let resultStringToResultError: result<'a, string> => result<'a, error> = n =>
-    n->E.R2.errMap(r => r->fromString->Error)
-}
-
-module Operation = {
-  type direction =
-    | Algebraic
-    | Pointwise
-
-  type arithmeticOperation = [
-    | #Add
-    | #Multiply
-    | #Subtract
-    | #Divide
-    | #Power
-    | #Logarithm
-  ]
-
-  let arithmeticToFn = (arithmetic: arithmeticOperation) =>
-    switch arithmetic {
-    | #Add => \"+."
-    | #Multiply => \"*."
-    | #Subtract => \"-."
-    | #Power => \"**"
-    | #Divide => \"/."
-    | #Logarithm => (a, b) => log(a) /. log(b)
-    }
-
-  type toFloat = [
-    | #Cdf(float)
-    | #Inv(float)
-    | #Mean
-    | #Pdf(float)
-    | #Sample
-  ]
-
-  @genType
-  type pointsetXSelection = [#Linear | #ByWeight]
-
-  type toDist =
-    | Normalize
-    | ToPointSet
-    | ToSampleSet(int)
-    | Truncate(option<float>, option<float>)
-    | Inspect
-
-  type toFloatArray = Sample(int)
-
-  type toString =
-    | ToString
-    | ToSparkline(int)
-
-  type toBool = IsNormalized
-
-  type fromDist =
-    | ToFloat(toFloat)
-    | ToDist(toDist)
-    | ToDistCombination(direction, arithmeticOperation, [#Dist(genericDist) | #Float(float)])
-    | ToString(toString)
-    | ToBool(toBool)
-
-  type singleParamaterFunction =
-    | FromDist(fromDist)
-    | FromFloat(fromDist)
-
-  @genType
-  type genericFunctionCallInfo =
-    | FromDist(fromDist, genericDist)
-    | FromFloat(fromDist, float)
-    | Mixture(array<(genericDist, float)>)
-
-  let distCallToString = (distFunction: fromDist): string =>
-    switch distFunction {
-    | ToFloat(#Cdf(r)) => `cdf(${E.Float.toFixed(r)})`
-    | ToFloat(#Inv(r)) => `inv(${E.Float.toFixed(r)})`
-    | ToFloat(#Mean) => `mean`
-    | ToFloat(#Pdf(r)) => `pdf(${E.Float.toFixed(r)})`
-    | ToFloat(#Sample) => `sample`
-    | ToDist(Normalize) => `normalize`
-    | ToDist(ToPointSet) => `toPointSet`
-    | ToDist(ToSampleSet(r)) => `toSampleSet(${E.I.toString(r)})`
-    | ToDist(Truncate(_, _)) => `truncate`
-    | ToDist(Inspect) => `inspect`
-    | ToString(ToString) => `toString`
-    | ToString(ToSparkline(n)) => `toSparkline(${E.I.toString(n)})`
-    | ToBool(IsNormalized) => `isNormalized`
-    | ToDistCombination(Algebraic, _, _) => `algebraic`
-    | ToDistCombination(Pointwise, _, _) => `pointwise`
-    }
-
-  let toString = (d: genericFunctionCallInfo): string =>
-    switch d {
-    | FromDist(f, _) | FromFloat(f, _) => distCallToString(f)
-    | Mixture(_) => `mixture`
-    }
-}
-
-/*
-It can be a pain to write out the genericFunctionCallInfo. The constructors help with this. 
-This code only covers some of genericFunctionCallInfo: many arguments could be called with either a
-float or a distribution. The "UsingDists" module assumes that everything is a distribution.
-This is a tradeoff of some generality in order to get a bit more simplicity.
-I could see having a longer interface in the future, but it could be messy.
-Like, algebraicAddDistFloat vs. algebraicAddDistDist
-*/
-module Constructors = {
-  type t = Operation.genericFunctionCallInfo
-
-  module UsingDists = {
-    @genType
-    let mean = (dist): t => FromDist(ToFloat(#Mean), dist)
-    let sample = (dist): t => FromDist(ToFloat(#Sample), dist)
-    let cdf = (dist, x): t => FromDist(ToFloat(#Cdf(x)), dist)
-    let inv = (dist, x): t => FromDist(ToFloat(#Inv(x)), dist)
-    let pdf = (dist, x): t => FromDist(ToFloat(#Pdf(x)), dist)
-    let normalize = (dist): t => FromDist(ToDist(Normalize), dist)
-    let isNormalized = (dist): t => FromDist(ToBool(IsNormalized), dist)
-    let toPointSet = (dist): t => FromDist(ToDist(ToPointSet), dist)
-    let toSampleSet = (dist, r): t => FromDist(ToDist(ToSampleSet(r)), dist)
-    let truncate = (dist, left, right): t => FromDist(ToDist(Truncate(left, right)), dist)
-    let inspect = (dist): t => FromDist(ToDist(Inspect), dist)
-    let toString = (dist): t => FromDist(ToString(ToString), dist)
-    let toSparkline = (dist, n): t => FromDist(ToString(ToSparkline(n)), dist)
-    let algebraicAdd = (dist1, dist2: genericDist): t => FromDist(
-      ToDistCombination(Algebraic, #Add, #Dist(dist2)),
-      dist1,
-    )
-    let algebraicMultiply = (dist1, dist2): t => FromDist(
-      ToDistCombination(Algebraic, #Multiply, #Dist(dist2)),
-      dist1,
-    )
-    let algebraicDivide = (dist1, dist2): t => FromDist(
-      ToDistCombination(Algebraic, #Divide, #Dist(dist2)),
-      dist1,
-    )
-    let algebraicSubtract = (dist1, dist2): t => FromDist(
-      ToDistCombination(Algebraic, #Subtract, #Dist(dist2)),
-      dist1,
-    )
-    let algebraicLogarithm = (dist1, dist2): t => FromDist(
-      ToDistCombination(Algebraic, #Logarithm, #Dist(dist2)),
-      dist1,
-    )
-    let algebraicPower = (dist1, dist2): t => FromDist(
-      ToDistCombination(Algebraic, #Power, #Dist(dist2)),
-      dist1,
-    )
-    let pointwiseAdd = (dist1, dist2): t => FromDist(
-      ToDistCombination(Pointwise, #Add, #Dist(dist2)),
-      dist1,
-    )
-    let pointwiseMultiply = (dist1, dist2): t => FromDist(
-      ToDistCombination(Pointwise, #Multiply, #Dist(dist2)),
-      dist1,
-    )
-    let pointwiseDivide = (dist1, dist2): t => FromDist(
-      ToDistCombination(Pointwise, #Divide, #Dist(dist2)),
-      dist1,
-    )
-    let pointwiseSubtract = (dist1, dist2): t => FromDist(
-      ToDistCombination(Pointwise, #Subtract, #Dist(dist2)),
-      dist1,
-    )
-    let pointwiseLogarithm = (dist1, dist2): t => FromDist(
-      ToDistCombination(Pointwise, #Logarithm, #Dist(dist2)),
-      dist1,
-    )
-    let pointwisePower = (dist1, dist2): t => FromDist(
-      ToDistCombination(Pointwise, #Power, #Dist(dist2)),
-      dist1,
-    )
-  }
-}
--- a/packages/squiggle-lang/src/rescript/Distributions/PointSetDist/Continuous.res
+++ b/packages/squiggle-lang/src/rescript/Distributions/PointSetDist/Continuous.res
@ -146,7 +146,27 @@ let reduce = (
  continuousShapes,
 ) => continuousShapes |> E.A.fold_left(combinePointwise(~integralSumCachesFn, fn), empty)

-let mapY = (~integralSumCacheFn=_ => None, ~integralCacheFn=_ => None, ~fn, t: t) =>
+let mapYResult = (
+  ~integralSumCacheFn=_ => None,
+  ~integralCacheFn=_ => None,
+  ~fn: float => result<float, 'e>,
+  t: t,
+): result<t, 'e> =>
+  XYShape.T.mapYResult(fn, getShape(t))->E.R2.fmap(x =>
+    make(
+      ~interpolation=t.interpolation,
+      ~integralSumCache=t.integralSumCache |> E.O.bind(_, integralSumCacheFn),
+      ~integralCache=t.integralCache |> E.O.bind(_, integralCacheFn),
+      x,
+    )
+  )
+
+let mapY = (
+  ~integralSumCacheFn=_ => None,
+  ~integralCacheFn=_ => None,
+  ~fn: float => float,
+  t: t,
+): t =>
  make(
    ~interpolation=t.interpolation,
    ~integralSumCache=t.integralSumCache |> E.O.bind(_, integralSumCacheFn),
@ -170,6 +190,7 @@ module T = Dist({
  let minX = shapeFn(XYShape.T.minX)
  let maxX = shapeFn(XYShape.T.maxX)
  let mapY = mapY
+  let mapYResult = mapYResult
  let updateIntegralCache = updateIntegralCache
  let toDiscreteProbabilityMassFraction = _ => 0.0
  let toPointSetDist = (t: t): PointSetTypes.pointSetDist => Continuous(t)
--- a/packages/squiggle-lang/src/rescript/Distributions/PointSetDist/Discrete.res
+++ b/packages/squiggle-lang/src/rescript/Distributions/PointSetDist/Discrete.res
@ -103,7 +103,26 @@ let combineAlgebraically = (op: Operation.convolutionOperation, t1: t, t2: t): t
  make(~integralSumCache=combinedIntegralSum, combinedShape)
 }

-let mapY = (~integralSumCacheFn=_ => None, ~integralCacheFn=_ => None, ~fn, t: t) =>
+let mapYResult = (
+  ~integralSumCacheFn=_ => None,
+  ~integralCacheFn=_ => None,
+  ~fn: float => result<float, 'e>,
+  t: t,
+): result<t, 'e> =>
+  XYShape.T.mapYResult(fn, getShape(t))->E.R2.fmap(x =>
+    make(
+      ~integralSumCache=t.integralSumCache |> E.O.bind(_, integralSumCacheFn),
+      ~integralCache=t.integralCache |> E.O.bind(_, integralCacheFn),
+      x,
+    )
+  )
+
+let mapY = (
+  ~integralSumCacheFn=_ => None,
+  ~integralCacheFn=_ => None,
+  ~fn: float => float,
+  t: t,
+): t =>
  make(
    ~integralSumCache=t.integralSumCache |> E.O.bind(_, integralSumCacheFn),
    ~integralCache=t.integralCache |> E.O.bind(_, integralCacheFn),
@ -143,6 +162,7 @@ module T = Dist({
  let maxX = shapeFn(XYShape.T.maxX)
  let toDiscreteProbabilityMassFraction = _ => 1.0
  let mapY = mapY
+  let mapYResult = mapYResult
  let updateIntegralCache = updateIntegralCache
  let toPointSetDist = (t: t): PointSetTypes.pointSetDist => Discrete(t)
  let toContinuous = _ => None
--- a/packages/squiggle-lang/src/rescript/Distributions/PointSetDist/Distributions.res
+++ b/packages/squiggle-lang/src/rescript/Distributions/PointSetDist/Distributions.res
@ -9,6 +9,12 @@ module type dist = {
    ~fn: float => float,
    t,
  ) => t
+  let mapYResult: (
+    ~integralSumCacheFn: float => option<float>=?,
+    ~integralCacheFn: PointSetTypes.continuousShape => option<PointSetTypes.continuousShape>=?,
+    ~fn: float => result<float, 'e>,
+    t,
+  ) => result<t, 'e>
  let xToY: (float, t) => PointSetTypes.mixedPoint
  let toPointSetDist: t => PointSetTypes.pointSetDist
  let toContinuous: t => option<PointSetTypes.continuousShape>
@ -37,6 +43,7 @@ module Dist = (T: dist) => {
  let integral = T.integral
  let xTotalRange = (t: t) => maxX(t) -. minX(t)
  let mapY = T.mapY
+  let mapYResult = T.mapYResult
  let xToY = T.xToY
  let downsample = T.downsample
  let toPointSetDist = T.toPointSetDist
--- a/packages/squiggle-lang/src/rescript/Distributions/PointSetDist/Mixed.res
+++ b/packages/squiggle-lang/src/rescript/Distributions/PointSetDist/Mixed.res
@ -164,7 +164,12 @@ module T = Dist({
  // This pipes all ys (continuous and discrete) through fn.
  // If mapY is a linear operation, we might be able to update the integralSumCaches as well;
  // if not, they'll be set to None.
-  let mapY = (~integralSumCacheFn=_ => None, ~integralCacheFn=_ => None, ~fn, t: t): t => {
+  let mapY = (
+    ~integralSumCacheFn=_ => None,
+    ~integralCacheFn=_ => None,
+    ~fn: float => float,
+    t: t,
+  ): t => {
    let yMappedDiscrete: PointSetTypes.discreteShape =
      t.discrete
      |> Discrete.T.mapY(~fn)
@ -187,6 +192,41 @@ module T = Dist({
    }
  }

+  let mapYResult = (
+    ~integralSumCacheFn=_ => None,
+    ~integralCacheFn=_ => None,
+    ~fn: float => result<float, 'e>,
+    t: t,
+  ): result<t, 'e> => {
+    E.R.merge(
+      Discrete.T.mapYResult(~fn, t.discrete),
+      Continuous.T.mapYResult(~fn, t.continuous),
+    )->E.R2.fmap(((discreteMapped, continuousMapped)) => {
+      let yMappedDiscrete: PointSetTypes.discreteShape =
+        discreteMapped
+        |> Discrete.updateIntegralSumCache(
+          E.O.bind(t.discrete.integralSumCache, integralSumCacheFn),
+        )
+        |> Discrete.updateIntegralCache(E.O.bind(t.discrete.integralCache, integralCacheFn))
+
+      let yMappedContinuous: PointSetTypes.continuousShape =
+        continuousMapped
+        |> Continuous.updateIntegralSumCache(
+          E.O.bind(t.continuous.integralSumCache, integralSumCacheFn),
+        )
+        |> Continuous.updateIntegralCache(E.O.bind(t.continuous.integralCache, integralCacheFn))
+
+      (
+        {
+          discrete: yMappedDiscrete,
+          continuous: yMappedContinuous,
+          integralSumCache: E.O.bind(t.integralSumCache, integralSumCacheFn),
+          integralCache: E.O.bind(t.integralCache, integralCacheFn),
+        }: t
+      )
+    })
+  }
+
  let mean = ({discrete, continuous}: t): float => {
    let discreteMean = Discrete.T.mean(discrete)
    let continuousMean = Continuous.T.mean(continuous)
--- a/packages/squiggle-lang/src/rescript/Distributions/PointSetDist/PointSetDist.res
+++ b/packages/squiggle-lang/src/rescript/Distributions/PointSetDist/PointSetDist.res
@ -16,6 +16,13 @@ let fmap = ((fn1, fn2, fn3), t: t): t =>
  | Continuous(m) => Continuous(fn3(m))
  }

+let fmapResult = ((fn1, fn2, fn3), t: t): result<t, 'e> =>
+  switch t {
+  | Mixed(m) => fn1(m)->E.R2.fmap(x => PointSetTypes.Mixed(x))
+  | Discrete(m) => fn2(m)->E.R2.fmap(x => PointSetTypes.Discrete(x))
+  | Continuous(m) => fn3(m)->E.R2.fmap(x => PointSetTypes.Continuous(x))
+  }
+
 let toMixed = mapToAll((
  m => m,
  d =>
@ -130,13 +137,26 @@ module T = Dist({
  let integralYtoX = f =>
    mapToAll((Mixed.T.Integral.yToX(f), Discrete.T.Integral.yToX(f), Continuous.T.Integral.yToX(f)))
  let maxX = mapToAll((Mixed.T.maxX, Discrete.T.maxX, Continuous.T.maxX))
-  let mapY = (~integralSumCacheFn=_ => None, ~integralCacheFn=_ => None, ~fn) =>
+  let mapY = (~integralSumCacheFn=_ => None, ~integralCacheFn=_ => None, ~fn: float => float): (
+    t => t
+  ) =>
    fmap((
      Mixed.T.mapY(~integralSumCacheFn, ~integralCacheFn, ~fn),
      Discrete.T.mapY(~integralSumCacheFn, ~integralCacheFn, ~fn),
      Continuous.T.mapY(~integralSumCacheFn, ~integralCacheFn, ~fn),
    ))

+  let mapYResult = (
+    ~integralSumCacheFn=_ => None,
+    ~integralCacheFn=_ => None,
+    ~fn: float => result<float, 'e>,
+  ): (t => result<t, 'e>) =>
+    fmapResult((
+      Mixed.T.mapYResult(~integralSumCacheFn, ~integralCacheFn, ~fn),
+      Discrete.T.mapYResult(~integralSumCacheFn, ~integralCacheFn, ~fn),
+      Continuous.T.mapYResult(~integralSumCacheFn, ~integralCacheFn, ~fn),
+    ))
+
  let mean = (t: t): float =>
    switch t {
    | Mixed(m) => Mixed.T.mean(m)
@ -195,8 +215,16 @@ let operate = (distToFloatOp: Operation.distToFloatOperation, s): float =>
  | #Mean => T.mean(s)
  }

-let toSparkline = (t: t, bucketCount) =>
+@genType
+type sparklineError = CannotSparklineDiscrete
+
+let sparklineErrorToString = (err: sparklineError): string =>
+  switch err {
+  | CannotSparklineDiscrete => "Cannot find the sparkline of a discrete distribution"
+  }
+
+let toSparkline = (t: t, bucketCount): result<string, sparklineError> =>
  T.toContinuous(t)
  ->E.O2.fmap(Continuous.downsampleEquallyOverX(bucketCount))
-  ->E.O2.toResult("toContinous Error: Could not convert into continuous distribution")
+  ->E.O2.toResult(CannotSparklineDiscrete)
  ->E.R2.fmap(r => Continuous.getShape(r).ys->Sparklines.create())
--- a/packages/squiggle-lang/src/rescript/Distributions/SampleSetDist/SampleSetDist.res
+++ b/packages/squiggle-lang/src/rescript/Distributions/SampleSetDist/SampleSetDist.res
@ -1,3 +1,11 @@
+@genType
+type sampleSetError = TooFewSamples
+
+let sampleSetErrorToString = (err: sampleSetError): string =>
+  switch err {
+  | TooFewSamples => "Too few samples when constructing sample set"
+  }
+
 /*
 This is used as a smart constructor. The only way to create a SampleSetDist.t is to call
 this constructor.
@ -8,7 +16,7 @@ module T: {
  //When we get a good functional library in TS, we could refactor that out.
  @genType
  type t = array<float>
-  let make: array<float> => result<t, string>
+  let make: array<float> => result<t, sampleSetError>
  let get: t => array<float>
 } = {
  type t = array<float>
@ -16,7 +24,7 @@ module T: {
    if E.A.length(a) > 5 {
      Ok(a)
    } else {
-      Error("too small")
+      Error(TooFewSamples)
    }
  let get = (a: t) => a
 }
@ -25,19 +33,27 @@ include T

 let length = (t: t) => get(t)->E.A.length

+@genType
+type pointsetConversionError = TooFewSamplesForConversionToPointSet
+
+let pointsetConversionErrorToString = (err: pointsetConversionError) =>
+  switch err {
+  | TooFewSamplesForConversionToPointSet => "Too Few Samples to convert to point set"
+  }
+
 /*
 TODO: Refactor to get a more precise estimate. Also, this code is just fairly messy, could use 
 some refactoring.
 */
 let toPointSetDist = (~samples: t, ~samplingInputs: SamplingInputs.samplingInputs): result<
  PointSetTypes.pointSetDist,
-  string,
+  pointsetConversionError,
 > =>
  SampleSetDist_ToPointSet.toPointSetDist(
    ~samples=get(samples),
    ~samplingInputs,
    (),
-  ).pointSetDist->E.O2.toResult("Failed to convert to PointSetDist")
+  ).pointSetDist->E.O2.toResult(TooFewSamplesForConversionToPointSet)

 //Randomly get one sample from the distribution
 let sample = (t: t): float => {
@ -62,7 +78,19 @@ let sampleN = (t: t, n) => {
 }

 //TODO: Figure out what to do if distributions are different lengths. ``zip`` is kind of inelegant for this.
-let map2 = (~fn: (float, float) => float, ~t1: t, ~t2: t) => {
+let map2 = (
+  ~fn: (float, float) => result<float, Operation.invalidOperationError>,
+  ~t1: t,
+  ~t2: t,
+): result<t, Operation.invalidOperationError> => {
  let samples = Belt.Array.zip(get(t1), get(t2))->E.A2.fmap(((a, b)) => fn(a, b))
-  make(samples)
+
+  // This assertion should never be reached. In order for it to be reached, one
+  // of the input parameters would need to be a sample set distribution with less
+  // than 6 samples. Which should be impossible due to the smart constructor.
+  // I could prove this to the type system (say, creating a {first: float, second: float, ..., fifth: float, rest: array<float>}
+  // But doing so would take too much time, so I'll leave it as an assertion
+  E.A.R.firstErrorOrOpen(samples)->E.R2.fmap(x =>
+    E.R.assertOk("Input of samples should be larger than 5", make(x))
+  )
 }
--- a/packages/squiggle-lang/src/rescript/Distributions/SampleSetDist/SampleSetDist_ToPointSet.res
+++ b/packages/squiggle-lang/src/rescript/Distributions/SampleSetDist/SampleSetDist_ToPointSet.res
@ -83,7 +83,7 @@ let toPointSetDist = (
  ~samples: Internals.T.t,
  ~samplingInputs: SamplingInputs.samplingInputs,
  (),
-) => {
+): Internals.Types.outputs => {
  Array.fast_sort(compare, samples)
  let (continuousPart, discretePart) = E.A.Sorted.Floats.split(samples)
  let length = samples |> E.A.length |> float_of_int
--- a/packages/squiggle-lang/src/rescript/Distributions/SymbolicDist/SymbolicDist.res
+++ b/packages/squiggle-lang/src/rescript/Distributions/SymbolicDist/SymbolicDist.res
@ -379,7 +379,7 @@ module T = {
  ): analyticalSimplificationResult =>
    switch (d1, d2) {
    | (#Float(v1), #Float(v2)) =>
-      switch Operation.Algebraic.applyFn(op, v1, v2) {
+      switch Operation.Algebraic.toFn(op, v1, v2) {
      | Ok(r) => #AnalyticalSolution(#Float(r))
      | Error(n) => #Error(n)
      }
--- a/packages/squiggle-lang/src/rescript/Distributions/SymbolicDist/SymbolicDistTypes.res
+++ b/packages/squiggle-lang/src/rescript/Distributions/SymbolicDist/SymbolicDistTypes.res
@ -45,6 +45,6 @@ type symbolicDist = [

 type analyticalSimplificationResult = [
  | #AnalyticalSolution(symbolicDist)
-  | #Error(string)
+  | #Error(Operation.invalidOperationError)
  | #NoSolution
 ]
--- a/packages/squiggle-lang/src/rescript/Reducer/Reducer_ErrorValue.res
+++ b/packages/squiggle-lang/src/rescript/Reducer/Reducer_ErrorValue.res
@ -9,6 +9,7 @@ type errorValue =
  | RERecordPropertyNotFound(string, string)
  | RESymbolNotFound(string)
  | RESyntaxError(string)
+  | REDistributionError(DistributionTypes.error)
  | RETodo(string) // To do

 type t = errorValue
@ -20,6 +21,7 @@ let errorToString = err =>
  | REAssignmentExpected => "Assignment expected"
  | REExpressionExpected => "Expression expected"
  | REFunctionExpected(msg) => `Function expected: ${msg}`
+  | REDistributionError(err) => `Math Error: ${DistributionTypes.Error.toString(err)}`
  | REJavaScriptExn(omsg, oname) => {
      let answer = "JS Exception:"
      let answer = switch oname {
--- a/packages/squiggle-lang/src/rescript/ReducerInterface/ReducerInterface_ExpressionValue.res
+++ b/packages/squiggle-lang/src/rescript/ReducerInterface/ReducerInterface_ExpressionValue.res
@ -10,7 +10,7 @@ type rec expressionValue =
  | EvArray(array<expressionValue>)
  | EvBool(bool)
  | EvCall(string) // External function call
-  | EvDistribution(GenericDist_Types.genericDist)
+  | EvDistribution(DistributionTypes.genericDist)
  | EvNumber(float)
  | EvRecord(Js.Dict.t<expressionValue>)
  | EvString(string)
--- a/packages/squiggle-lang/src/rescript/ReducerInterface/ReducerInterface_GenericDistribution.res
+++ b/packages/squiggle-lang/src/rescript/ReducerInterface/ReducerInterface_GenericDistribution.res
@ -29,8 +29,8 @@ module Helpers = {
    }

  let catchAndConvertTwoArgsToDists = (args: array<expressionValue>): option<(
-    GenericDist_Types.genericDist,
-    GenericDist_Types.genericDist,
+    DistributionTypes.genericDist,
+    DistributionTypes.genericDist,
  )> => {
    switch args {
    | [EvDistribution(a), EvDistribution(b)] => Some((a, b))
@ -41,33 +41,41 @@ module Helpers = {
  }

  let toFloatFn = (
-    fnCall: GenericDist_Types.Operation.toFloat,
-    dist: GenericDist_Types.genericDist,
+    fnCall: DistributionTypes.Operation.toFloat,
+    dist: DistributionTypes.genericDist,
  ) => {
-    FromDist(GenericDist_Types.Operation.ToFloat(fnCall), dist)->runGenericOperation->Some
+    FromDist(DistributionTypes.DistributionOperation.ToFloat(fnCall), dist)
+    ->runGenericOperation
+    ->Some
  }

  let toStringFn = (
-    fnCall: GenericDist_Types.Operation.toString,
-    dist: GenericDist_Types.genericDist,
+    fnCall: DistributionTypes.DistributionOperation.toString,
+    dist: DistributionTypes.genericDist,
  ) => {
-    FromDist(GenericDist_Types.Operation.ToString(fnCall), dist)->runGenericOperation->Some
+    FromDist(DistributionTypes.DistributionOperation.ToString(fnCall), dist)
+    ->runGenericOperation
+    ->Some
  }

  let toBoolFn = (
-    fnCall: GenericDist_Types.Operation.toBool,
-    dist: GenericDist_Types.genericDist,
+    fnCall: DistributionTypes.DistributionOperation.toBool,
+    dist: DistributionTypes.genericDist,
  ) => {
-    FromDist(GenericDist_Types.Operation.ToBool(fnCall), dist)->runGenericOperation->Some
+    FromDist(DistributionTypes.DistributionOperation.ToBool(fnCall), dist)
+    ->runGenericOperation
+    ->Some
  }

-  let toDistFn = (fnCall: GenericDist_Types.Operation.toDist, dist) => {
-    FromDist(GenericDist_Types.Operation.ToDist(fnCall), dist)->runGenericOperation->Some
+  let toDistFn = (fnCall: DistributionTypes.DistributionOperation.toDist, dist) => {
+    FromDist(DistributionTypes.DistributionOperation.ToDist(fnCall), dist)
+    ->runGenericOperation
+    ->Some
  }

  let twoDiststoDistFn = (direction, arithmetic, dist1, dist2) => {
    FromDist(
-      GenericDist_Types.Operation.ToDistCombination(
+      DistributionTypes.DistributionOperation.ToDistCombination(
        direction,
        arithmeticMap(arithmetic),
        #Dist(dist2),
@ -84,7 +92,7 @@ module Helpers = {
  let parseNumberArray = (ags: array<expressionValue>): Belt.Result.t<array<float>, string> =>
    E.A.fmap(parseNumber, ags) |> E.A.R.firstErrorOrOpen

-  let parseDist = (args: expressionValue): Belt.Result.t<GenericDist_Types.genericDist, string> =>
+  let parseDist = (args: expressionValue): Belt.Result.t<DistributionTypes.genericDist, string> =>
    switch args {
    | EvDistribution(x) => Ok(x)
    | EvNumber(x) => Ok(GenericDist.fromFloat(x))
@ -92,12 +100,12 @@ module Helpers = {
    }

  let parseDistributionArray = (ags: array<expressionValue>): Belt.Result.t<
-    array<GenericDist_Types.genericDist>,
+    array<DistributionTypes.genericDist>,
    string,
  > => E.A.fmap(parseDist, ags) |> E.A.R.firstErrorOrOpen

  let mixtureWithGivenWeights = (
-    distributions: array<GenericDist_Types.genericDist>,
+    distributions: array<DistributionTypes.genericDist>,
    weights: array<float>,
  ): DistributionOperation.outputType =>
    E.A.length(distributions) == E.A.length(weights)
@ -107,7 +115,7 @@ module Helpers = {
        )

  let mixtureWithDefaultWeights = (
-    distributions: array<GenericDist_Types.genericDist>,
+    distributions: array<DistributionTypes.genericDist>,
  ): DistributionOperation.outputType => {
    let length = E.A.length(distributions)
    let weights = Belt.Array.make(length, 1.0 /. Belt.Int.toFloat(length))
@ -259,12 +267,7 @@ let genericOutputToReducerValue = (o: DistributionOperation.outputType): result<
  | Float(d) => Ok(EvNumber(d))
  | String(d) => Ok(EvString(d))
  | Bool(d) => Ok(EvBool(d))
-  | GenDistError(NotYetImplemented) => Error(RETodo("Function not yet implemented"))
-  | GenDistError(Unreachable) => Error(RETodo("Unreachable"))
-  | GenDistError(DistributionVerticalShiftIsInvalid) =>
-    Error(RETodo("Distribution Vertical Shift Is Invalid"))
-  | GenDistError(ArgumentError(err)) => Error(RETodo("Argument Error: " ++ err))
-  | GenDistError(Other(s)) => Error(RETodo(s))
+  | GenDistError(err) => Error(REDistributionError(err))
  }

 let dispatch = call => {
--- a/packages/squiggle-lang/src/rescript/TypescriptInterface.res
+++ b/packages/squiggle-lang/src/rescript/TypescriptInterface.res
@ -53,4 +53,4 @@ type continuousShape = PointSetTypes.continuousShape
 let errorValueToString = Reducer_ErrorValue.errorToString

@genType
-let distributionErrorToString = GenericDist_Types.Error.toString
+let distributionErrorToString = DistributionTypes.Error.toString
--- a/packages/squiggle-lang/src/rescript/Utility/E.res
+++ b/packages/squiggle-lang/src/rescript/Utility/E.res
@ -152,6 +152,8 @@ module I = {
  let toString = Js.Int.toString
 }

+exception Assertion(string)
+
 /* R for Result */
 module R = {
  let result = Rationale.Result.result
@ -159,6 +161,11 @@ module R = {
  let fmap = Rationale.Result.fmap
  let bind = Rationale.Result.bind
  let toExn = Belt.Result.getExn
+  let assertOk = (message: string, x: result<'a, 'b>): 'a =>
+    switch x {
+    | Ok(r) => r
+    | Error(_) => raise(Assertion(message))
+    }
  let default = (default, res: Belt.Result.t<'a, 'b>) =>
    switch res {
    | Ok(r) => r
@ -210,10 +217,10 @@ module R2 = {
  let bind = (a, b) => R.bind(b, a)

  //Converts result type to change error type only
-  let errMap = (a, map) =>
+  let errMap = (a: result<'a, 'b>, map: 'b => 'c): result<'a, 'c> =>
    switch a {
    | Ok(r) => Ok(r)
-    | Error(e) => map(e)
+    | Error(e) => Error(map(e))
    }

  let fmap2 = (xR, f) =>
@ -436,6 +443,7 @@ module A = {
        r |> Belt.Array.map(_, r => Belt.Result.getExn(r))
      bringErrorUp |> Belt.Result.map(_, forceOpen)
    }
+    let filterOk = (x: array<result<'a, 'b>>): array<'a> => fmap(R.toOption, x)->O.concatSomes
  }

  module Sorted = {
--- a/packages/squiggle-lang/src/rescript/Utility/Operation.res
+++ b/packages/squiggle-lang/src/rescript/Utility/Operation.res
@ -37,22 +37,42 @@ module Convolution = {
    }
 }

+@genType
+type invalidOperationError =
+  | DivisionByZeroError
+  | ComplexNumberError
+
+let invalidOperationErrorToString = (err: invalidOperationError): string =>
+  switch err {
+  | DivisionByZeroError => "Cannot divide by zero"
+  | ComplexNumberError => "Operation returned complex result"
+  }
+
 module Algebraic = {
  type t = algebraicOperation
-  let toFn: (t, float, float) => float = x =>
+  let toFn: (t, float, float) => result<float, invalidOperationError> = (x, a, b) =>
    switch x {
-    | #Add => \"+."
-    | #Subtract => \"-."
-    | #Multiply => \"*."
-    | #Power => \"**"
-    | #Divide => \"/."
-    | #Logarithm => (a, b) => log(a) /. log(b)
-    }
-
-  let applyFn = (t, f1, f2) =>
-    switch (t, f1, f2) {
-    | (#Divide, _, 0.) => Error("Cannot divide $v1 by zero.")
-    | _ => Ok(toFn(t, f1, f2))
+    | #Add => Ok(a +. b)
+    | #Subtract => Ok(a -. b)
+    | #Multiply => Ok(a *. b)
+    | #Power =>
+      if a > 0.0 {
+        Ok(a ** b)
+      } else {
+        Error(ComplexNumberError)
+      }
+    | #Divide =>
+      if b != 0.0 {
+        Ok(a /. b)
+      } else {
+        Error(DivisionByZeroError)
+      }
+    | #Logarithm =>
+      if a > 0.0 && b > 0.0 {
+        Ok(log(a) /. log(b))
+      } else {
+        Error(ComplexNumberError)
+      }
    }

  let toString = x =>
@ -96,12 +116,27 @@ module DistToFloat = {
 // Note that different logarithms don't really do anything.
 module Scale = {
  type t = scaleOperation
-  let toFn = x =>
+  let toFn = (x: t, a: float, b: float): result<float, invalidOperationError> =>
    switch x {
-    | #Multiply => \"*."
-    | #Divide => \"/."
-    | #Power => \"**"
-    | #Logarithm => (a, b) => log(a) /. log(b)
+    | #Multiply => Ok(a *. b)
+    | #Divide =>
+      if b != 0.0 {
+        Ok(a /. b)
+      } else {
+        Error(DivisionByZeroError)
+      }
+    | #Power =>
+      if a > 0.0 {
+        Ok(a ** b)
+      } else {
+        Error(ComplexNumberError)
+      }
+    | #Logarithm =>
+      if a > 0.0 && b > 0.0 {
+        Ok(log(a) /. log(b))
+      } else {
+        Error(DivisionByZeroError)
+      }
    }

  let format = (operation: t, value, scaleBy) =>
--- a/packages/squiggle-lang/src/rescript/Utility/XYShape.res
+++ b/packages/squiggle-lang/src/rescript/Utility/XYShape.res
@ -43,6 +43,10 @@ module T = {
  let xTotalRange = (t: t) => maxX(t) -. minX(t)
  let mapX = (fn, t: t): t => {xs: E.A.fmap(fn, t.xs), ys: t.ys}
  let mapY = (fn, t: t): t => {xs: t.xs, ys: E.A.fmap(fn, t.ys)}
+  let mapYResult = (fn: float => result<float, 'e>, t: t): result<t, 'e> => {
+    let mappedYs = E.A.fmap(fn, t.ys)
+    E.A.R.firstErrorOrOpen(mappedYs)->E.R2.fmap(y => {xs: t.xs, ys: y})
+  }
  let square = mapX(x => x ** 2.0)
  let zip = ({xs, ys}: t) => Belt.Array.zip(xs, ys)
  let fromArray = ((xs, ys)): t => {xs: xs, ys: ys}