Merge remote-tracking branch 'origin/develop' into fix-nixbuild

.github/CODEOWNERS

@@ -9,22 +9,22 @@
 # This also holds true for GitHub teams.
 
 # Rescript 
-*.res @OAGr
+*.res @berekuk @OAGr
-*.resi @OAGr
+*.resi @berekuk @OAGr
 
 # Typescript 
-*.tsx @Hazelfire @OAGr
+*.tsx @Hazelfire @berekuk @OAGr 
-*.ts @Hazelfire @OAGr
+*.ts @Hazelfire @berekuk @OAGr
 
 # Javascript
-*.js @Hazelfire @OAGr
+*.js @Hazelfire @berekuk @OAGr
 
 # Any opsy files
-.github/** @quinn-dougherty @OAGr
+.github/** @quinn-doughert @berekuky @OAGr
-*.json @quinn-dougherty @Hazelfire @OAGr
+*.json @quinn-dougherty @Hazelfire @berekuk @OAGr
-*.y*ml @quinn-dougherty @OAGr
+*.y*ml @quinn-dougherty @berekuk @OAGr
-*.config.js @Hazelfire @OAGr
+*.config.js @Hazelfire @berekuk @OAGr
-netlify.toml @quinn-dougherty @OAGr @Hazelfire 
+netlify.toml @quinn-dougherty @OAGr @berekuk @Hazelfire 
 
 # Documentation
 *.md @quinn-dougherty @OAGr @Hazelfire

packages/squiggle-lang/__tests__/Reducer/Reducer_TestMacroHelpers.res

@@ -19,7 +19,7 @@ let testMacro_ = (
   let bindings = Bindings.fromArray(bindArray)
   tester(expr->T.toString, () =>
     expr
-    ->Macro.expandMacroCall(
+    ->Macro.expandMacroCallRs(
       bindings,
       ProjectAccessorsT.identityAccessors,
       Expression.reduceExpressionInProject,
@@ -44,6 +44,7 @@ let testMacroEval_ = (
       ProjectAccessorsT.identityAccessors,
       Expression.reduceExpressionInProject,
     )
+    ->Ok
     ->InternalExpressionValue.toStringResult
     ->expect
     ->toEqual(expectedValue)

packages/squiggle-lang/__tests__/Reducer/Reducer_Type/Reducer_Type_TypeChecker_arguments_test.res

@@ -16,7 +16,7 @@ let checkArgumentsSourceCode = (aTypeSourceCode: string, sourceCode: string): re
 > => {
   let reducerFn = Expression.reduceExpressionInProject
   let rResult =
-    Expression.BackCompatible.parse(sourceCode)->Belt.Result.flatMap(expr =>
+    Expression.BackCompatible.parse(sourceCode)->Belt.Result.map(expr =>
       reducerFn(expr, Bindings.emptyBindings, ProjectAccessorsT.identityAccessors)
     )
   rResult->Belt.Result.flatMap(result =>

packages/squiggle-lang/__tests__/Reducer/Reducer_Type/Reducer_Type_TypeChecker_test.res

@@ -19,7 +19,7 @@ let isTypeOfSourceCode = (aTypeSourceCode: string, sourceCode: string): result<
 > => {
   let reducerFn = Expression.reduceExpressionInProject
   let rResult =
-    Expression.BackCompatible.parse(sourceCode)->Belt.Result.flatMap(expr =>
+    Expression.BackCompatible.parse(sourceCode)->Belt.Result.map(expr =>
       reducerFn(expr, Bindings.emptyBindings, ProjectAccessorsT.identityAccessors)
     )
   rResult->Belt.Result.flatMap(result => TypeChecker.isTypeOf(aTypeSourceCode, result, reducerFn))

packages/squiggle-lang/__tests__/Reducer/Reducer_test.res

@@ -56,7 +56,7 @@ describe("test exceptions", () => {
   testDescriptionEvalToBe(
     "javascript exception",
     "javascriptraise('div by 0')",
-    "Error(JS Exception: Error: 'div by 0')",
+    "Error(Error: 'div by 0')",
   )
   // testDescriptionEvalToBe(
   //   "rescript exception",

packages/squiggle-lang/src/rescript/FunctionRegistry/Library/FR_Danger.res

@@ -74,12 +74,11 @@ module Integration = {
           reducer,
         )
         let result = switch resultAsInternalExpression {
-        | Ok(IEvNumber(x)) => Ok(x)
+        | IEvNumber(x) => Ok(x)
-        | Error(_) =>
+        | _ =>
           Error(
             "Error 1 in Danger.integrate. It's possible that your function doesn't return a number, try definining auxiliaryFunction(x) = mean(yourFunction(x)) and integrate auxiliaryFunction instead",
           )
-        | _ => Error("Error 2 in Danger.integrate")
         }
         result
       }
@@ -143,7 +142,7 @@ module Integration = {
         }
       | Error(b) =>
         Error(
-          "Integration error 3 in Danger.integrate. It's possible that your function doesn't return a number, try definining auxiliaryFunction(x) = mean(yourFunction(x)) and integrate auxiliaryFunction instead." ++
+          "Integration error 2 in Danger.integrate. It's possible that your function doesn't return a number, try definining auxiliaryFunction(x) = mean(yourFunction(x)) and integrate auxiliaryFunction instead." ++
           "Original error: " ++
           b,
         )
@@ -309,14 +308,10 @@ module DiminishingReturns = {
               reducer,
             )
             switch resultAsInternalExpression {
-            | Ok(IEvNumber(x)) => Ok(x)
+            | IEvNumber(x) => Ok(x)
-            | Error(_) =>
-              Error(
-                "Error 1 in Danger.optimalAllocationGivenDiminishingMarginalReturnsForManyFunctions. It's possible that your function doesn't return a number, try definining auxiliaryFunction(x) = mean(yourFunction(x)) and integrate auxiliaryFunction instead",
-              )
             | _ =>
               Error(
-                "Error 2 in Danger.optimalAllocationGivenDiminishingMarginalReturnsForManyFunctions",
+                "Error 1 in Danger.optimalAllocationGivenDiminishingMarginalReturnsForManyFunctions. It's possible that your function doesn't return a number, try definining auxiliaryFunction(x) = mean(yourFunction(x)) and integrate auxiliaryFunction instead",
               )
             }
           }

packages/squiggle-lang/src/rescript/FunctionRegistry/Library/FR_List.res

@@ -32,19 +32,15 @@ module Internals = {
     accessors: ProjectAccessorsT.t,
     eLambdaValue,
     reducer: ProjectReducerFnT.t,
-  ): result<ReducerInterface_InternalExpressionValue.t, Reducer_ErrorValue.errorValue> => {
+  ): ReducerInterface_InternalExpressionValue.t => {
-    let rMappedList = array->E.A.reduceReverse(Ok(list{}), (rAcc, elem) =>
+    Belt.Array.map(array, elem =>
-      rAcc->E.R.bind(_, acc => {
+      Reducer_Expression_Lambda.doLambdaCall(
-        let rNewElem = Reducer_Expression_Lambda.doLambdaCall(
         eLambdaValue,
         list{elem},
         (accessors: ProjectAccessorsT.t),
         (reducer: ProjectReducerFnT.t),
       )
-        rNewElem->E.R2.fmap(newElem => list{newElem, ...acc})
+    )->Wrappers.evArray
-      })
-    )
-    rMappedList->E.R2.fmap(mappedList => mappedList->Belt.List.toArray->Wrappers.evArray)
   }
 
   let reduce = (
@@ -54,11 +50,9 @@ module Internals = {
     accessors: ProjectAccessorsT.t,
     reducer: ProjectReducerFnT.t,
   ) => {
-    aValueArray->E.A.reduce(Ok(initialValue), (rAcc, elem) =>
+    aValueArray->E.A.reduce(initialValue, (acc, elem) =>
-      rAcc->E.R.bind(_, acc =>
       Reducer_Expression_Lambda.doLambdaCall(aLambdaValue, list{acc, elem}, accessors, reducer)
     )
-    )
   }
 
   let reduceReverse = (
@@ -68,11 +62,9 @@ module Internals = {
     accessors: ProjectAccessorsT.t,
     reducer: ProjectReducerFnT.t,
   ) => {
-    aValueArray->Belt.Array.reduceReverse(Ok(initialValue), (rAcc, elem) =>
+    aValueArray->Belt.Array.reduceReverse(initialValue, (acc, elem) =>
-      rAcc->Belt.Result.flatMap(acc =>
       Reducer_Expression_Lambda.doLambdaCall(aLambdaValue, list{acc, elem}, accessors, reducer)
     )
-    )
   }
 
   let filter = (
@@ -81,25 +73,18 @@ module Internals = {
     accessors: ProjectAccessorsT.t,
     reducer: ProjectReducerFnT.t,
   ) => {
-    let rMappedList = aValueArray->Belt.Array.reduceReverse(Ok(list{}), (rAcc, elem) =>
+    Js.Array2.filter(aValueArray, elem => {
-      rAcc->E.R.bind(_, acc => {
+      let result = Reducer_Expression_Lambda.doLambdaCall(
-        let rNewElem = Reducer_Expression_Lambda.doLambdaCall(
         aLambdaValue,
         list{elem},
         accessors,
         reducer,
       )
-        rNewElem->E.R2.fmap(newElem => {
+      switch result {
-          switch newElem {
+      | IEvBool(true) => true
-          | IEvBool(true) => list{elem, ...acc}
+      | _ => false
-          | _ => acc
       }
-        })
+    })->Wrappers.evArray
-      })
-    )
-    let result =
-      rMappedList->E.R2.fmap(mappedList => mappedList->Belt.List.toArray->Wrappers.evArray)
-    result
   }
 }
 
@@ -216,7 +201,7 @@ let library = [
         ~run=(inputs, _, accessors: ProjectAccessorsT.t, reducer) =>
           switch inputs {
           | [IEvArray(array), IEvLambda(lambda)] =>
-            Internals.map(array, accessors, lambda, reducer)->E.R2.errMap(_ => "Error!")
+            Ok(Internals.map(array, accessors, lambda, reducer))
           | _ => Error(impossibleError)
           },
         (),
@@ -236,9 +221,7 @@ let library = [
         ~run=(inputs, _, accessors: ProjectAccessorsT.t, reducer) =>
           switch inputs {
           | [IEvArray(array), initialValue, IEvLambda(lambda)] =>
-            Internals.reduce(array, initialValue, lambda, accessors, reducer)->E.R2.errMap(_ =>
+            Ok(Internals.reduce(array, initialValue, lambda, accessors, reducer))
-              "Error!"
-            )
           | _ => Error(impossibleError)
           },
         (),
@@ -258,13 +241,7 @@ let library = [
         ~run=(inputs, _, accessors: ProjectAccessorsT.t, reducer: ProjectReducerFnT.t) =>
           switch inputs {
           | [IEvArray(array), initialValue, IEvLambda(lambda)] =>
-            Internals.reduceReverse(
+            Ok(Internals.reduceReverse(array, initialValue, lambda, accessors, reducer))
-              array,
-              initialValue,
-              lambda,
-              accessors,
-              reducer,
-            )->E.R2.errMap(_ => "Error!")
           | _ => Error(impossibleError)
           },
         (),
@@ -284,7 +261,7 @@ let library = [
         ~run=(inputs, _, accessors: ProjectAccessorsT.t, reducer: ProjectReducerFnT.t) =>
           switch inputs {
           | [IEvArray(array), IEvLambda(lambda)] =>
-            Internals.filter(array, lambda, accessors, reducer)->E.R2.errMap(_ => "Error!")
+            Ok(Internals.filter(array, lambda, accessors, reducer))
           | _ => Error(impossibleError)
           },
         (),

packages/squiggle-lang/src/rescript/FunctionRegistry/Library/FR_Pointset.res

@@ -37,7 +37,7 @@ module Internal = {
 
   let doLambdaCall = (aLambdaValue, list, environment, reducer) =>
     switch Reducer_Expression_Lambda.doLambdaCall(aLambdaValue, list, environment, reducer) {
-    | Ok(IEvNumber(f)) => Ok(f)
+    | IEvNumber(f) => Ok(f)
     | _ => Error(Operation.SampleMapNeedsNtoNFunction)
     }
 

packages/squiggle-lang/src/rescript/FunctionRegistry/Library/FR_Sampleset.res

@@ -16,7 +16,7 @@ module Internal = {
     reducer: ProjectReducerFnT.t,
   ) =>
     switch Reducer_Expression_Lambda.doLambdaCall(aLambdaValue, list, accessors, reducer) {
-    | Ok(IEvNumber(f)) => Ok(f)
+    | IEvNumber(f) => Ok(f)
     | _ => Error(Operation.SampleMapNeedsNtoNFunction)
     }
 

packages/squiggle-lang/src/rescript/Reducer/Reducer_Dispatch/Reducer_Dispatch_BuiltIn.res

@@ -3,6 +3,7 @@ module BindingsReplacer = Reducer_Expression_BindingsReplacer
 module Continuation = ReducerInterface_Value_Continuation
 module ExpressionT = Reducer_Expression_T
 module ExternalLibrary = ReducerInterface.ExternalLibrary
+module InternalExpressionValue = ReducerInterface_InternalExpressionValue
 module Lambda = Reducer_Expression_Lambda
 module MathJs = Reducer_MathJs
 module ProjectAccessorsT = ReducerProject_ProjectAccessors_T
@@ -111,7 +112,7 @@ let callInternal = (
   module SampleMap = {
     let doLambdaCall = (aLambdaValue, list) =>
       switch Lambda.doLambdaCall(aLambdaValue, list, accessors, reducer) {
-      | Ok(IEvNumber(f)) => Ok(f)
+      | IEvNumber(f) => Ok(f)
       | _ => Error(Operation.SampleMapNeedsNtoNFunction)
       }
 
@@ -201,13 +202,17 @@ let dispatch = (
   call: functionCall,
   accessors: ProjectAccessorsT.t,
   reducer: ProjectReducerFnT.t,
-): result<internalExpressionValue, errorValue> =>
+): internalExpressionValue =>
   try {
     let (fn, args) = call
     // There is a bug that prevents string match in patterns
     // So we have to recreate a copy of the string
-    ExternalLibrary.dispatch((Js.String.make(fn), args), accessors, reducer, callInternal)
+    ExternalLibrary.dispatch(
+      (Js.String.make(fn), args),
+      accessors,
+      reducer,
+      callInternal,
+    )->InternalExpressionValue.resultToValue
   } catch {
-  | Js.Exn.Error(obj) => REJavaScriptExn(Js.Exn.message(obj), Js.Exn.name(obj))->Error
+  | exn => Reducer_ErrorValue.fromException(exn)->Reducer_ErrorValue.toException
-  | _ => RETodo("unhandled rescript exception")->Error
   }

packages/squiggle-lang/src/rescript/Reducer/Reducer_Dispatch/Reducer_Dispatch_BuiltInMacros.res

@@ -12,11 +12,9 @@ module ExpressionWithContext = Reducer_ExpressionWithContext
 module InternalExpressionValue = ReducerInterface_InternalExpressionValue
 module ProjectAccessorsT = ReducerProject_ProjectAccessors_T
 module ProjectReducerFnT = ReducerProject_ReducerFn_T
-module Result = Belt.Result
 
 open Reducer_Expression_ExpressionBuilder
 
-type errorValue = ErrorValue.errorValue
 type expression = ExpressionT.expression
 type expressionWithContext = ExpressionWithContext.expressionWithContext
 
@@ -25,21 +23,15 @@ let dispatchMacroCall = (
   bindings: ExpressionT.bindings,
   accessors: ProjectAccessorsT.t,
   reduceExpression: ProjectReducerFnT.t,
-): result<expressionWithContext, errorValue> => {
+): expressionWithContext => {
   let useExpressionToSetBindings = (bindingExpr: expression, accessors, statement, newCode) => {
-    let rExternalBindingsValue = reduceExpression(bindingExpr, bindings, accessors)
+    let nameSpaceValue = reduceExpression(bindingExpr, bindings, accessors)
 
-    rExternalBindingsValue->Result.flatMap(nameSpaceValue => {
     let newBindings = Bindings.fromExpressionValue(nameSpaceValue)
 
-      let rNewStatement = BindingsReplacer.replaceSymbols(newBindings, statement)
+    let boundStatement = BindingsReplacer.replaceSymbols(newBindings, statement)
-      rNewStatement->Result.map(boundStatement =>
+
-        ExpressionWithContext.withContext(
+    ExpressionWithContext.withContext(newCode(newBindings->eModule, boundStatement), newBindings)
-          newCode(newBindings->eModule, boundStatement),
-          newBindings,
-        )
-      )
-    })
   }
 
   let correspondingSetBindingsFn = (fnName: string): string =>
@@ -52,7 +44,7 @@ let dispatchMacroCall = (
     }
 
   let doBindStatement = (bindingExpr: expression, statement: expression, accessors) => {
-    let defaultStatement = ErrorValue.REAssignmentExpected->Error
+    let defaultStatement = ErrorValue.REAssignmentExpected
     switch statement {
     | ExpressionT.EList(list{ExpressionT.EValue(IEvCall(callName)), symbolExpr, statement}) => {
         let setBindingsFn = correspondingSetBindingsFn(callName)
@@ -62,17 +54,18 @@ let dispatchMacroCall = (
             boundStatement,
           ) => eFunction(setBindingsFn, list{newBindingsExpr, symbolExpr, boundStatement}))
         } else {
-          defaultStatement
+          defaultStatement->Reducer_ErrorValue.toException
         }
       }
-    | _ => defaultStatement
+    | _ => defaultStatement->Reducer_ErrorValue.toException
     }
   }
 
-  let doBindExpression = (bindingExpr: expression, statement: expression, accessors): result<
+  let doBindExpression = (
-    expressionWithContext,
+    bindingExpr: expression,
-    errorValue,
+    statement: expression,
-  > => {
+    accessors,
+  ): expressionWithContext => {
     let defaultStatement = () =>
       useExpressionToSetBindings(bindingExpr, accessors, statement, (
         _newBindingsExpr,
@@ -100,10 +93,11 @@ let dispatchMacroCall = (
     }
   }
 
-  let doBlock = (exprs: list<expression>, _bindings: ExpressionT.bindings, _accessors): result<
+  let doBlock = (
-    expressionWithContext,
+    exprs: list<expression>,
-    errorValue,
+    _bindings: ExpressionT.bindings,
-  > => {
+    _accessors,
+  ): expressionWithContext => {
     let exprsArray = Belt.List.toArray(exprs)
     let maxIndex = Js.Array2.length(exprsArray) - 1
     let newStatement = exprsArray->Js.Array2.reducei((acc, statement, index) =>
@@ -119,14 +113,14 @@ let dispatchMacroCall = (
         eBindStatement(acc, statement)
       }
     , eSymbol("undefined block"))
-    ExpressionWithContext.noContext(newStatement)->Ok
+    ExpressionWithContext.noContext(newStatement)
   }
 
   let doLambdaDefinition = (
     bindings: ExpressionT.bindings,
     parameters: array<string>,
     lambdaDefinition: ExpressionT.expression,
-  ) => ExpressionWithContext.noContext(eLambda(parameters, bindings, lambdaDefinition))->Ok
+  ) => ExpressionWithContext.noContext(eLambda(parameters, bindings, lambdaDefinition))
 
   let doTernary = (
     condition: expression,
@@ -134,28 +128,28 @@ let dispatchMacroCall = (
     ifFalse: expression,
     bindings: ExpressionT.bindings,
     accessors,
-  ): result<expressionWithContext, errorValue> => {
+  ): expressionWithContext => {
     let blockCondition = ExpressionBuilder.eBlock(list{condition})
-    let rCondition = reduceExpression(blockCondition, bindings, accessors)
+    let conditionValue = reduceExpression(blockCondition, bindings, accessors)
-    rCondition->Result.flatMap(conditionValue =>
+
     switch conditionValue {
     | InternalExpressionValue.IEvBool(false) => {
         let ifFalseBlock = eBlock(list{ifFalse})
-          ExpressionWithContext.withContext(ifFalseBlock, bindings)->Ok
+        ExpressionWithContext.withContext(ifFalseBlock, bindings)
       }
     | InternalExpressionValue.IEvBool(true) => {
         let ifTrueBlock = eBlock(list{ifTrue})
-          ExpressionWithContext.withContext(ifTrueBlock, bindings)->Ok
+        ExpressionWithContext.withContext(ifTrueBlock, bindings)
       }
-      | _ => REExpectedType("Boolean", "")->Error
+    | _ => REExpectedType("Boolean", "")->Reducer_ErrorValue.toException
     }
-    )
   }
 
-  let expandExpressionList = (aList, bindings: ExpressionT.bindings, accessors): result<
+  let expandExpressionList = (
-    expressionWithContext,
+    aList,
-    errorValue,
+    bindings: ExpressionT.bindings,
-  > =>
+    accessors,
+  ): expressionWithContext =>
     switch aList {
     | list{
         ExpressionT.EValue(IEvCall("$$_bindStatement_$$")),
@@ -185,11 +179,11 @@ let dispatchMacroCall = (
       doLambdaDefinition(bindings, parameters, lambdaDefinition)
     | list{ExpressionT.EValue(IEvCall("$$_ternary_$$")), condition, ifTrue, ifFalse} =>
       doTernary(condition, ifTrue, ifFalse, bindings, accessors)
-    | _ => ExpressionWithContext.noContext(ExpressionT.EList(aList))->Ok
+    | _ => ExpressionWithContext.noContext(ExpressionT.EList(aList))
     }
 
   switch macroExpression {
   | EList(aList) => expandExpressionList(aList, bindings, accessors)
-  | _ => ExpressionWithContext.noContext(macroExpression)->Ok
+  | _ => ExpressionWithContext.noContext(macroExpression)
   }
 }

packages/squiggle-lang/src/rescript/Reducer/Reducer_ErrorValue.res

@@ -26,6 +26,8 @@ type errorValue =
 
 type t = errorValue
 
+exception ErrorException(errorValue)
+
 let errorToString = err =>
   switch err {
   | REArityError(_oFnName, arity, usedArity) =>
@@ -62,3 +64,20 @@ let errorToString = err =>
   | RENeedToRun => "Need to run"
   | REOther(msg) => `Error: ${msg}`
   }
+
+let fromException = exn =>
+  switch exn {
+  | ErrorException(e) => e
+  | Js.Exn.Error(e) =>
+    switch Js.Exn.message(e) {
+    | Some(message) => REOther(message)
+    | None =>
+      switch Js.Exn.name(e) {
+      | Some(name) => REOther(name)
+      | None => REOther("Unknown error")
+      }
+    }
+  | _e => REOther("Unknown error")
+  }
+
+let toException = (errorValue: t) => raise(ErrorException(errorValue))

packages/squiggle-lang/src/rescript/Reducer/Reducer_Expression/Reducer_Expression.res

@@ -21,10 +21,10 @@ let rec reduceExpressionInProject = (
   expression: t,
   continuation: T.bindings,
   accessors: ProjectAccessorsT.t,
-): result<InternalExpressionValue.t, 'e> => {
+): InternalExpressionValue.t => {
   // Js.log(`reduce: ${T.toString(expression)} bindings: ${bindings->Bindings.toString}`)
   switch expression {
-  | T.EValue(value) => value->Ok
+  | T.EValue(value) => value
   | T.EList(list) =>
     switch list {
     | list{EValue(IEvCall(fName)), ..._args} =>
@@ -41,20 +41,12 @@ and reduceExpressionList = (
   expressions: list<t>,
   continuation: T.bindings,
   accessors: ProjectAccessorsT.t,
-): result<InternalExpressionValue.t, 'e> => {
+): InternalExpressionValue.t => {
-  let racc: result<
+  let acc: list<InternalExpressionValue.t> =
-    list<InternalExpressionValue.t>,
+    expressions->Belt.List.reduceReverse(list{}, (acc, each: t) =>
-    'e,
+      acc->Belt.List.add(each->reduceExpressionInProject(continuation, accessors))
-  > = expressions->Belt.List.reduceReverse(Ok(list{}), (racc, each: t) =>
-    racc->Result.flatMap(acc => {
-      each
-      ->reduceExpressionInProject(continuation, accessors)
-      ->Result.map(newNode => {
-        acc->Belt.List.add(newNode)
-      })
-    })
     )
-  racc->Result.flatMap(acc => acc->reduceValueList(accessors))
+  acc->reduceValueList(accessors)
 }
 
 /*
@@ -63,48 +55,34 @@ and reduceExpressionList = (
 and reduceValueList = (
   valueList: list<InternalExpressionValue.t>,
   accessors: ProjectAccessorsT.t,
-): result<InternalExpressionValue.t, 'e> =>
+): InternalExpressionValue.t =>
   switch valueList {
   | list{IEvCall(fName), ...args} => {
-      let rCheckedArgs = switch fName {
+      let checkedArgs = switch fName {
-      | "$_setBindings_$" | "$_setTypeOfBindings_$" | "$_setTypeAliasBindings_$" => args->Ok
+      | "$_setBindings_$" | "$_setTypeOfBindings_$" | "$_setTypeAliasBindings_$" => args
       | _ => args->Lambda.checkIfReduced
       }
 
-      rCheckedArgs->Result.flatMap(checkedArgs =>
       (fName, checkedArgs->Belt.List.toArray)->BuiltIn.dispatch(
         accessors,
         reduceExpressionInProject,
       )
-      )
     }
   | list{IEvLambda(_)} =>
     // TODO: remove on solving issue#558
-    valueList
+    valueList->Lambda.checkIfReduced->Belt.List.toArray->InternalExpressionValue.IEvArray
-    ->Lambda.checkIfReduced
-    ->Result.flatMap(reducedValueList =>
-      reducedValueList->Belt.List.toArray->InternalExpressionValue.IEvArray->Ok
-    )
   | list{IEvLambda(lambdaCall), ...args} =>
     args
     ->Lambda.checkIfReduced
-    ->Result.flatMap(checkedArgs =>
+    ->Lambda.doLambdaCall(lambdaCall, _, accessors, reduceExpressionInProject)
-      Lambda.doLambdaCall(lambdaCall, checkedArgs, accessors, reduceExpressionInProject)
+  | _ => valueList->Lambda.checkIfReduced->Belt.List.toArray->InternalExpressionValue.IEvArray
-    )
-
-  | _ =>
-    valueList
-    ->Lambda.checkIfReduced
-    ->Result.flatMap(reducedValueList =>
-      reducedValueList->Belt.List.toArray->InternalExpressionValue.IEvArray->Ok
-    )
   }
 
 let reduceReturningBindings = (
   expression: t,
   continuation: T.bindings,
   accessors: ProjectAccessorsT.t,
-): (result<InternalExpressionValue.t, 'e>, T.bindings) => {
+): (InternalExpressionValue.t, T.bindings) => {
   let states = accessors.states
   let result = reduceExpressionInProject(expression, continuation, accessors)
   (result, states.continuation)
@@ -118,7 +96,11 @@ module BackCompatible = {
 
   let evaluate = (expression: t): result<InternalExpressionValue.t, errorValue> => {
     let accessors = ProjectAccessorsT.identityAccessors
-    expression->reduceExpressionInProject(accessors.stdLib, accessors)
+    try {
+      expression->reduceExpressionInProject(accessors.stdLib, accessors)->Ok
+    } catch {
+    | exn => Reducer_ErrorValue.fromException(exn)->Error
+    }
   }
 
   let evaluateString = (peggyCode: string): result<InternalExpressionValue.t, errorValue> =>

packages/squiggle-lang/src/rescript/Reducer/Reducer_Expression/Reducer_ExpressionWithContext.res

@@ -18,12 +18,14 @@ type expressionWithContext =
   | ExpressionWithContext(expression, context)
   | ExpressionNoContext(expression)
 
+type t = expressionWithContext
+
 let callReducer = (
   expressionWithContext: expressionWithContext,
   bindings: bindings,
   accessors: ProjectAccessorsT.t,
   reducer: ProjectReducerFnT.t,
-): result<internalExpressionValue, errorValue> => {
+): internalExpressionValue => {
   switch expressionWithContext {
   | ExpressionNoContext(expr) =>
     // Js.log(`callReducer: bindings ${Bindings.toString(bindings)} expr ${ExpressionT.toString(expr)}`)
@@ -51,3 +53,10 @@ let toStringResult = rExpressionWithContext =>
   | Ok(expressionWithContext) => `Ok(${toString(expressionWithContext)})`
   | Error(errorValue) => ErrorValue.errorToString(errorValue)
   }
+
+let resultToValue = (rExpressionWithContext: result<t, errorValue>): t => {
+  switch rExpressionWithContext {
+  | Ok(expressionWithContext) => expressionWithContext
+  | Error(errorValue) => ErrorValue.toException(errorValue)
+  }
+}

packages/squiggle-lang/src/rescript/Reducer/Reducer_Expression/Reducer_Expression_BindingsReplacer.res

@@ -1,7 +1,6 @@
 module ErrorValue = Reducer_ErrorValue
 module ExpressionT = Reducer_Expression_T
 module InternalExpressionValue = ReducerInterface_InternalExpressionValue
-module Result = Belt.Result
 module Bindings = Reducer_Bindings
 
 type errorValue = Reducer_ErrorValue.errorValue
@@ -10,19 +9,15 @@ type internalExpressionValue = InternalExpressionValue.t
 
 let isMacroName = (fName: string): bool => fName->Js.String2.startsWith("$$")
 
-let rec replaceSymbols = (bindings: ExpressionT.bindings, expression: expression): result<
+let rec replaceSymbols = (bindings: ExpressionT.bindings, expression: expression): expression =>
-  expression,
-  errorValue,
-> =>
   switch expression {
-  | ExpressionT.EValue(value) =>
+  | ExpressionT.EValue(value) => replaceSymbolOnValue(bindings, value)->ExpressionT.EValue
-    replaceSymbolOnValue(bindings, value)->Result.map(evValue => evValue->ExpressionT.EValue)
   | ExpressionT.EList(list) =>
     switch list {
     | list{EValue(IEvCall(fName)), ..._args} =>
       switch isMacroName(fName) {
       // A macro reduces itself so we dont dive in it
-      | true => expression->Ok
+      | true => expression
       | false => replaceSymbolsOnExpressionList(bindings, list)
       }
     | _ => replaceSymbolsOnExpressionList(bindings, list)
@@ -30,23 +25,21 @@ let rec replaceSymbols = (bindings: ExpressionT.bindings, expression: expression
   }
 
 and replaceSymbolsOnExpressionList = (bindings, list) => {
-  let racc = list->Belt.List.reduceReverse(Ok(list{}), (racc, each: expression) =>
+  let racc =
-    racc->Result.flatMap(acc => {
+    list->Belt.List.reduceReverse(list{}, (acc, each: expression) =>
-      replaceSymbols(bindings, each)->Result.flatMap(newNode => {
+      replaceSymbols(bindings, each)->Belt.List.add(acc, _)
-        acc->Belt.List.add(newNode)->Ok
-      })
-    })
     )
-  racc->Result.map(acc => acc->ExpressionT.EList)
+  ExpressionT.EList(racc)
 }
 and replaceSymbolOnValue = (bindings, evValue: internalExpressionValue) =>
   switch evValue {
-  | IEvSymbol(symbol) => Bindings.getWithDefault(bindings, symbol, evValue)->Ok
+  | IEvSymbol(symbol) => Bindings.getWithDefault(bindings, symbol, evValue)
   | IEvCall(symbol) => Bindings.getWithDefault(bindings, symbol, evValue)->checkIfCallable
-  | _ => evValue->Ok
+  | _ => evValue
   }
 and checkIfCallable = (evValue: internalExpressionValue) =>
   switch evValue {
-  | IEvCall(_) | IEvLambda(_) => evValue->Ok
+  | IEvCall(_) | IEvLambda(_) => evValue
-  | _ => ErrorValue.RENotAFunction(InternalExpressionValue.toString(evValue))->Error
+  | _ =>
+    ErrorValue.RENotAFunction(InternalExpressionValue.toString(evValue))->ErrorValue.toException
   }

packages/squiggle-lang/src/rescript/Reducer/Reducer_Expression/Reducer_Expression_Lambda.res

@@ -23,27 +23,25 @@ let checkArity = (
     let argsLength = Belt.List.length(args)
     let parametersLength = Js.Array2.length(lambdaValue.parameters)
     if argsLength !== parametersLength {
-      ErrorValue.REArityError(None, parametersLength, argsLength)->Error
+      ErrorValue.REArityError(None, parametersLength, argsLength)->ErrorValue.toException
     } else {
-      args->Ok
+      args
     }
   }
   let exprOrFFI = castInternalCodeToExpression(lambdaValue.body)
   switch exprOrFFI {
   | NotFFI(_) => reallyCheck
-  | FFI(_) => args->Ok
+  | FFI(_) => args
   }
 }
 
 let checkIfReduced = (args: list<internalExpressionValue>) =>
-  args->Belt.List.reduceReverse(Ok(list{}), (rAcc, arg) =>
+  args->Belt.List.reduceReverse(list{}, (acc, arg) =>
-    rAcc->Result.flatMap(acc =>
     switch arg {
-      | IEvSymbol(symbol) => ErrorValue.RESymbolNotFound(symbol)->Error
+    | IEvSymbol(symbol) => ErrorValue.RESymbolNotFound(symbol)->ErrorValue.toException
-      | _ => list{arg, ...acc}->Ok
+    | _ => list{arg, ...acc}
     }
   )
-  )
 
 let caseNotFFI = (
   lambdaValue: ExpressionValue.lambdaValue,
@@ -63,7 +61,10 @@ let caseNotFFI = (
 }
 
 let caseFFI = (ffiFn: ExpressionT.ffiFn, args, accessors: ProjectAccessorsT.t) => {
-  ffiFn(args->Belt.List.toArray, accessors.environment)
+  switch ffiFn(args->Belt.List.toArray, accessors.environment) {
+  | Ok(value) => value
+  | Error(value) => value->ErrorValue.toException
+  }
 }
 
 let applyParametersToLambda = (
@@ -71,16 +72,13 @@ let applyParametersToLambda = (
   args,
   accessors: ProjectAccessorsT.t,
   reducer: ProjectReducerFnT.t,
-): result<internalExpressionValue, 'e> => {
+): internalExpressionValue => {
-  checkArity(lambdaValue, args)->Result.flatMap(args =>
+  let args = checkArity(lambdaValue, args)->checkIfReduced
-    checkIfReduced(args)->Result.flatMap(args => {
   let exprOrFFI = castInternalCodeToExpression(lambdaValue.body)
   switch exprOrFFI {
   | NotFFI(expr) => caseNotFFI(lambdaValue, expr, args, accessors, reducer)
   | FFI(ffiFn) => caseFFI(ffiFn, args, accessors)
   }
-    })
-  )
 }
 
 let doLambdaCall = (
@@ -95,7 +93,7 @@ let foreignFunctionInterface = (
   argArray: array<internalExpressionValue>,
   accessors: ProjectAccessorsT.t,
   reducer: ProjectReducerFnT.t,
-): result<internalExpressionValue, Reducer_ErrorValue.errorValue> => {
+): internalExpressionValue => {
   let args = argArray->Belt.List.fromArray
   applyParametersToLambda(lambdaValue, args, accessors, reducer)
 }

packages/squiggle-lang/src/rescript/Reducer/Reducer_Expression/Reducer_Expression_Macro.res

@@ -10,32 +10,34 @@ type expression = ExpressionT.expression
 type internalExpressionValue = InternalExpressionValue.t
 type expressionWithContext = ExpressionWithContext.expressionWithContext
 
-let expandMacroCall = (
+let expandMacroCallRs = (
   macroExpression: expression,
   bindings: ExpressionT.bindings,
   accessors: ProjectAccessorsT.t,
   reduceExpression: ProjectReducerFnT.t,
 ): result<expressionWithContext, 'e> =>
+  try {
     Reducer_Dispatch_BuiltInMacros.dispatchMacroCall(
       macroExpression,
       bindings,
       accessors,
       reduceExpression,
-  )
+    )->Ok
+  } catch {
+  | exn => Reducer_ErrorValue.fromException(exn)->Error
+  }
 
 let doMacroCall = (
   macroExpression: expression,
   bindings: ExpressionT.bindings,
   accessors: ProjectAccessorsT.t,
   reduceExpression: ProjectReducerFnT.t,
-): result<internalExpressionValue, 'e> =>
+): internalExpressionValue =>
-  expandMacroCall(
+  Reducer_Dispatch_BuiltInMacros.dispatchMacroCall(
     macroExpression,
     bindings,
     (accessors: ProjectAccessorsT.t),
     (reduceExpression: ProjectReducerFnT.t),
-  )->Result.flatMap(expressionWithContext =>
+  )->ExpressionWithContext.callReducer(bindings, accessors, reduceExpression)
-    ExpressionWithContext.callReducer(expressionWithContext, bindings, accessors, reduceExpression)
-  )
 
 let isMacroName = (fName: string): bool => fName->Js.String2.startsWith("$$")

packages/squiggle-lang/src/rescript/Reducer/Reducer_Expression/Reducer_Expression_T.res

@@ -82,3 +82,9 @@ type optionFfiFnReturningResult = (
 type expressionOrFFI =
   | NotFFI(expression)
   | FFI(ffiFn)
+
+let resultToValue = (rExpression: result<t, Reducer_ErrorValue.t>): t =>
+  switch rExpression {
+  | Ok(expression) => expression
+  | Error(errorValue) => Reducer_ErrorValue.toException(errorValue)
+  }

packages/squiggle-lang/src/rescript/Reducer/Reducer_Type/Reducer_Type_Compile.res

@@ -15,17 +15,13 @@ let ievFromTypeExpression = (
   let sourceCode = `type ${sIndex}=${typeExpressionSourceCode}`
   Reducer_Expression.BackCompatible.parse(sourceCode)->Belt.Result.flatMap(expr => {
     let accessors = ProjectAccessorsT.identityAccessors
-    let result = reducerFn(expr, Bindings.emptyBindings, accessors)
+    let _result = reducerFn(expr, Bindings.emptyBindings, accessors)
     let nameSpace = accessors.states.continuation
 
-    switch result {
-    | Ok(_) =>
     switch Bindings.getType(nameSpace, sIndex) {
     | Some(value) => value->Ok
     | None => raise(Reducer_Exception.ImpossibleException("Reducer_Type_Compile-none"))
     }
-    | err => err
-    }
   })
 }
 

packages/squiggle-lang/src/rescript/ReducerInterface/ReducerInterface_InternalExpressionValue.res

@@ -244,3 +244,9 @@ let nameSpaceGet = (nameSpace: nameSpace, key: string): option<t> => {
   let NameSpace(container) = nameSpace
   container->Belt.Map.String.get(key)
 }
+
+let resultToValue = (rExpression: result<t, Reducer_ErrorValue.t>): t =>
+  switch rExpression {
+  | Ok(expression) => expression
+  | Error(errorValue) => Reducer_ErrorValue.toException(errorValue)
+  }

packages/squiggle-lang/src/rescript/ReducerProject/ReducerProject_ProjectItem.res

@@ -183,17 +183,6 @@ let buildExpression = (this: t): t => {
   }
 }
 
-let wrappedReducer = (
-  rExpression: T.expressionArgumentType,
-  aContinuation: T.continuation,
-  accessors: ProjectAccessorsT.t,
-): T.resultArgumentType => {
-  Belt.Result.flatMap(
-    rExpression,
-    Reducer_Expression.reduceExpressionInProject(_, aContinuation, accessors),
-  )
-}
-
 let doBuildResult = (
   this: t,
   aContinuation: T.continuation,
@@ -202,9 +191,12 @@ let doBuildResult = (
   this
   ->getExpression
   ->Belt.Option.map(
-    Belt.Result.flatMap(
+    Belt.Result.flatMap(_, expression =>
-      _,
+      try {
-      Reducer_Expression.reduceExpressionInProject(_, aContinuation, accessors),
+        Reducer_Expression.reduceExpressionInProject(expression, aContinuation, accessors)->Ok
+      } catch {
+      | exn => Reducer_ErrorValue.fromException(exn)->Error
+      }
     ),
   )
 

packages/squiggle-lang/src/rescript/ReducerProject/ReducerProject_ReducerFn_T.res

@@ -2,8 +2,4 @@ module ExpressionT = Reducer_Expression_T
 module InternalExpressionValue = ReducerInterface_InternalExpressionValue
 module ProjectAccessorsT = ReducerProject_ProjectAccessors_T
 
-type t = (
+type t = (ExpressionT.t, ExpressionT.bindings, ProjectAccessorsT.t) => InternalExpressionValue.t
-  ExpressionT.t,
-  ExpressionT.bindings,
-  ProjectAccessorsT.t,
-) => result<InternalExpressionValue.t, Reducer_ErrorValue.errorValue>

packages/squiggle-lang/src/rescript/Utility/E.res

@@ -5,912 +5,23 @@ running `rescript convert -all` on Rationale https://github.com/jonlaing/rationa
 
 let equals = (a, b) => a === b
 
-module FloatFloatMap = {
+module A = E_A
-  module Id = Belt.Id.MakeComparable({
+module A2 = E_A2
-    type t = float
+module B = E_B
-    let cmp: (float, float) => int = Pervasives.compare
+module Dict = E_Dict
-  })
+module F = E_F
-
+module Float = E_Float
-  type t = Belt.MutableMap.t<Id.t, float, Id.identity>
+module FloatFloatMap = E_FloatFloatMap
-
+module I = E_I
-  let fromArray = (ar: array<(float, float)>) => Belt.MutableMap.fromArray(ar, ~id=module(Id))
+module Int = E_Int
-  let toArray = (t: t): array<(float, float)> => Belt.MutableMap.toArray(t)
+module J = E_J
-  let empty = () => Belt.MutableMap.make(~id=module(Id))
+module JsDate = E_JsDate
-  let increment = (el, t: t) =>
+module L = E_L
-    Belt.MutableMap.update(t, el, x =>
+module O = E_O
-      switch x {
+module O2 = E_O2
-      | Some(n) => Some(n +. 1.0)
+module R = E_R
-      | None => Some(1.0)
+module R2 = E_R2
-      }
+module S = E_S
-    )
+module Tuple2 = E_Tuple2
-
+module Tuple3 = E_Tuple3
-  let get = (el, t: t) => Belt.MutableMap.get(t, el)
+module U = E_U
-  let fmap = (fn, t: t) => Belt.MutableMap.map(t, fn)
-  let partition = (fn, t: t) => {
-    let (match, noMatch) = Belt.Array.partition(toArray(t), fn)
-    (fromArray(match), fromArray(noMatch))
-  }
-}
-
-module Int = {
-  let max = (i1: int, i2: int) => i1 > i2 ? i1 : i2
-  let random = (~min, ~max) => Js.Math.random_int(min, max)
-}
-/* Utils */
-module U = {
-  let isEqual = \"=="
-  let toA = a => [a]
-  let id = e => e
-}
-
-module Tuple2 = {
-  let first = (v: ('a, 'b)) => {
-    let (a, _) = v
-    a
-  }
-  let second = (v: ('a, 'b)) => {
-    let (_, b) = v
-    b
-  }
-  let toFnCall = (fn, (a1, a2)) => fn(a1, a2)
-}
-
-module Tuple3 = {
-  let toFnCall = (fn, (a1, a2, a3)) => fn(a1, a2, a3)
-}
-
-module O = {
-  let dimap = (sFn, rFn, e) =>
-    switch e {
-    | Some(r) => sFn(r)
-    | None => rFn()
-    }
-  ()
-  let fmap = (f: 'a => 'b, x: option<'a>): option<'b> => {
-    switch x {
-    | None => None
-    | Some(x') => Some(f(x'))
-    }
-  }
-  let bind = (o, f) =>
-    switch o {
-    | None => None
-    | Some(a) => f(a)
-    }
-  let default = (d, o) =>
-    switch o {
-    | None => d
-    | Some(a) => a
-    }
-  let defaultFn = (d, o) =>
-    switch o {
-    | None => d()
-    | Some(a) => a
-    }
-  let isSome = o =>
-    switch o {
-    | Some(_) => true
-    | _ => false
-    }
-  let isNone = o =>
-    switch o {
-    | None => true
-    | _ => false
-    }
-  let toExn = (err, o) =>
-    switch o {
-    | None => raise(Failure(err))
-    | Some(a) => a
-    }
-
-  let some = a => Some(a)
-  let firstSome = (a, b) =>
-    switch a {
-    | None => b
-    | _ => a
-    }
-
-  let toExt = toExn
-
-  let flatten = o =>
-    switch o {
-    | None => None
-    | Some(x) => x
-    }
-
-  let apply = (o, a) =>
-    switch o {
-    | Some(f) => bind(a, b => some(f(b)))
-    | _ => None
-    }
-  let flatApply = (fn, b) => apply(fn, Some(b)) |> flatten
-
-  let toBool = opt =>
-    switch opt {
-    | Some(_) => true
-    | _ => false
-    }
-
-  let ffmap = (fn, r) =>
-    switch r {
-    | Some(sm) => fn(sm)
-    | _ => None
-    }
-
-  let toString = opt =>
-    switch opt {
-    | Some(s) => s
-    | _ => ""
-    }
-
-  let toResult = (error, e) =>
-    switch e {
-    | Some(r) => Belt.Result.Ok(r)
-    | None => Error(error)
-    }
-
-  let compare = (compare, f1: option<float>, f2: option<float>) =>
-    switch (f1, f2) {
-    | (Some(f1), Some(f2)) => Some(compare(f1, f2) ? f1 : f2)
-    | (Some(f1), None) => Some(f1)
-    | (None, Some(f2)) => Some(f2)
-    | (None, None) => None
-    }
-
-  let min = compare(\"<")
-  let max = compare(\">")
-}
-
-module O2 = {
-  let default = (a, b) => O.default(b, a)
-  let defaultFn = (a, b) => O.defaultFn(b, a)
-  let toExn = (a, b) => O.toExn(b, a)
-  let fmap = (a, b) => O.fmap(b, a)
-  let toResult = (a, b) => O.toResult(b, a)
-  let bind = (a, b) => O.bind(b, a)
-}
-
-/* Functions */
-module F = {
-  let pipe = (f, g, x) => g(f(x))
-  let compose = (f, g, x) => f(g(x))
-  let flip = (f, a, b) => f(b, a)
-  let always = (x, _y) => x
-
-  let apply = (a, e) => a |> e
-
-  let flatten2Callbacks = (fn1, fn2, fnlast) =>
-    fn1(response1 => fn2(response2 => fnlast(response1, response2)))
-
-  let flatten3Callbacks = (fn1, fn2, fn3, fnlast) =>
-    fn1(response1 => fn2(response2 => fn3(response3 => fnlast(response1, response2, response3))))
-
-  let flatten4Callbacks = (fn1, fn2, fn3, fn4, fnlast) =>
-    fn1(response1 =>
-      fn2(response2 =>
-        fn3(response3 => fn4(response4 => fnlast(response1, response2, response3, response4)))
-      )
-    )
-}
-
-module Bool = {
-  type t = bool
-  let toString = (t: t) => t ? "TRUE" : "FALSE"
-  let fromString = str => str == "TRUE" ? true : false
-
-  module O = {
-    let toBool = opt =>
-      switch opt {
-      | Some(true) => true
-      | _ => false
-      }
-  }
-}
-
-module Float = {
-  let with2DigitsPrecision = Js.Float.toPrecisionWithPrecision(_, ~digits=2)
-  let with3DigitsPrecision = Js.Float.toPrecisionWithPrecision(_, ~digits=3)
-  let toFixed = Js.Float.toFixed
-  let toString = Js.Float.toString
-  let isFinite = Js.Float.isFinite
-  let toInt = Belt.Float.toInt
-}
-
-module I = {
-  let increment = n => n + 1
-  let decrement = n => n - 1
-  let toString = Js.Int.toString
-  let toFloat = Js.Int.toFloat
-}
-
-exception Assertion(string)
-
-/* R for Result */
-module R = {
-  open Belt.Result
-  let result = (okF, errF, r) =>
-    switch r {
-    | Ok(a) => okF(a)
-    | Error(err) => errF(err)
-    }
-  let id = e => e |> result(U.id, U.id)
-  let isOk = Belt.Result.isOk
-  let getError = (r: result<'a, 'b>) =>
-    switch r {
-    | Ok(_) => None
-    | Error(e) => Some(e)
-    }
-  let fmap = (f: 'a => 'b, r: result<'a, 'c>): result<'b, 'c> => {
-    switch r {
-    | Ok(r') => Ok(f(r'))
-    | Error(err) => Error(err)
-    }
-  }
-  let bind = (r, f) =>
-    switch r {
-    | Ok(a) => f(a)
-    | Error(err) => Error(err)
-    }
-  let toExn = (msg: string, x: result<'a, 'b>): 'a =>
-    switch x {
-    | Ok(r) => r
-    | Error(_) => raise(Assertion(msg))
-    }
-  let toExnFnString = (errorToStringFn, o) =>
-    switch o {
-    | Ok(r) => r
-    | Error(r) => raise(Assertion(errorToStringFn(r)))
-    }
-  let default = (default, res: Belt.Result.t<'a, 'b>) =>
-    switch res {
-    | Ok(r) => r
-    | Error(_) => default
-    }
-  let merge = (a, b) =>
-    switch (a, b) {
-    | (Error(e), _) => Error(e)
-    | (_, Error(e)) => Error(e)
-    | (Ok(a), Ok(b)) => Ok((a, b))
-    }
-  let toOption = (e: Belt.Result.t<'a, 'b>) =>
-    switch e {
-    | Ok(r) => Some(r)
-    | Error(_) => None
-    }
-
-  let errorIfCondition = (errorCondition, errorMessage, r) =>
-    errorCondition(r) ? Error(errorMessage) : Ok(r)
-
-  let ap = (r, a) =>
-    switch r {
-    | Ok(f) => Ok(f(a))
-    | Error(err) => Error(err)
-    }
-  let ap' = (r, a) =>
-    switch r {
-    | Ok(f) => fmap(f, a)
-    | Error(err) => Error(err)
-    }
-
-  let liftM2: (('a, 'b) => 'c, result<'a, 'd>, result<'b, 'd>) => result<'c, 'd> = (op, xR, yR) => {
-    ap'(fmap(op, xR), yR)
-  }
-
-  let liftJoin2: (('a, 'b) => result<'c, 'd>, result<'a, 'd>, result<'b, 'd>) => result<'c, 'd> = (
-    op,
-    xR,
-    yR,
-  ) => {
-    bind(liftM2(op, xR, yR), x => x)
-  }
-
-  let fmap2 = (f, r) =>
-    switch r {
-    | Ok(r) => r->Ok
-    | Error(x) => x->f->Error
-    }
-
-  //I'm not sure what to call this.
-  let unify = (a: result<'a, 'b>, c: 'b => 'a): 'a =>
-    switch a {
-    | Ok(x) => x
-    | Error(x) => c(x)
-    }
-}
-
-module R2 = {
-  let fmap = (a, b) => R.fmap(b, a)
-  let bind = (a, b) => R.bind(b, a)
-
-  //Converts result type to change error type only
-  let errMap = (a: result<'a, 'b>, map: 'b => 'c): result<'a, 'c> =>
-    switch a {
-    | Ok(r) => Ok(r)
-    | Error(e) => Error(map(e))
-    }
-
-  let fmap2 = (xR, f) =>
-    switch xR {
-    | Ok(x) => x->Ok
-    | Error(x) => x->f->Error
-    }
-
-  let toExn = (a, b) => R.toExn(b, a)
-}
-
-let safe_fn_of_string = (fn, s: string): option<'a> =>
-  try Some(fn(s)) catch {
-  | _ => None
-  }
-
-module S = {
-  let safe_float = float_of_string->safe_fn_of_string
-  let safe_int = int_of_string->safe_fn_of_string
-  let default = (defaultStr, str) => str == "" ? defaultStr : str
-}
-
-module J = {
-  let toString = F.pipe(Js.Json.decodeString, O.default(""))
-  let fromString = Js.Json.string
-  let fromNumber = Js.Json.number
-
-  module O = {
-    let fromString = (str: string) =>
-      switch str {
-      | "" => None
-      | _ => Some(Js.Json.string(str))
-      }
-
-    let toString = (str: option<'a>) =>
-      switch str {
-      | Some(str) => Some(str |> F.pipe(Js.Json.decodeString, O.default("")))
-      | _ => None
-      }
-  }
-}
-
-module JsDate = {
-  let fromString = Js.Date.fromString
-  let now = Js.Date.now
-  let make = Js.Date.make
-  let valueOf = Js.Date.valueOf
-}
-
-/* List */
-module L = {
-  module Util = {
-    let eq = \"=="
-  }
-  let fmap = List.map
-  let get = Belt.List.get
-  let toArray = Array.of_list
-  let fmapi = List.mapi
-  let concat = List.concat
-  let concat' = (xs, ys) => List.append(ys, xs)
-
-  let rec drop = (i, xs) =>
-    switch (i, xs) {
-    | (_, list{}) => list{}
-    | (i, _) if i <= 0 => xs
-    | (i, list{_, ...b}) => drop(i - 1, b)
-    }
-
-  let append = (a, xs) => List.append(xs, list{a})
-  let take = {
-    let rec loop = (i, xs, acc) =>
-      switch (i, xs) {
-      | (i, _) if i <= 0 => acc
-      | (_, list{}) => acc
-      | (i, list{a, ...b}) => loop(i - 1, b, append(a, acc))
-      }
-    (i, xs) => loop(i, xs, list{})
-  }
-  let takeLast = (i, xs) => List.rev(xs) |> take(i) |> List.rev
-
-  let splitAt = (i, xs) => (take(i, xs), takeLast(List.length(xs) - i, xs))
-  let remove = (i, n, xs) => {
-    let (a, b) = splitAt(i, xs)
-    \"@"(a, drop(n, b))
-  }
-
-  let find = List.find
-  let filter = List.filter
-  let for_all = List.for_all
-  let exists = List.exists
-  let sort = List.sort
-  let length = List.length
-
-  let filter_opt = xs => {
-    let rec loop = (l, acc) =>
-      switch l {
-      | list{} => acc
-      | list{hd, ...tl} =>
-        switch hd {
-        | None => loop(tl, acc)
-        | Some(x) => loop(tl, list{x, ...acc})
-        }
-      }
-    List.rev(loop(xs, list{}))
-  }
-
-  let containsWith = f => List.exists(f)
-
-  let uniqWithBy = (eq, f, xs) =>
-    List.fold_left(
-      ((acc, tacc), v) =>
-        containsWith(eq(f(v)), tacc) ? (acc, tacc) : (append(v, acc), append(f(v), tacc)),
-      (list{}, list{}),
-      xs,
-    ) |> fst
-
-  let uniqBy = (f, xs) => uniqWithBy(Util.eq, f, xs)
-  let join = j => List.fold_left((acc, v) => String.length(acc) == 0 ? v : acc ++ (j ++ v), "")
-
-  let head = xs =>
-    switch List.hd(xs) {
-    | exception _ => None
-    | a => Some(a)
-    }
-
-  let uniq = xs => uniqBy(x => x, xs)
-  let flatten = List.flatten
-  let last = xs => xs |> List.rev |> head
-  let append = List.append
-  let getBy = Belt.List.getBy
-  let dropLast = (i, xs) => take(List.length(xs) - i, xs)
-  let containsWith = f => List.exists(f)
-  let contains = x => containsWith(Util.eq(x))
-
-  let reject = pred => List.filter(x => !pred(x))
-  let tail = xs =>
-    switch List.tl(xs) {
-    | exception _ => None
-    | a => Some(a)
-    }
-
-  let init = xs => {
-    O.fmap(List.rev, xs |> List.rev |> tail)
-  }
-
-  let singleton = (x: 'a): list<'a> => list{x}
-
-  let adjust = (f, i, xs) => {
-    let (a, b) = splitAt(i + 1, xs)
-    switch a {
-    | _ if i < 0 => xs
-    | _ if i >= List.length(xs) => xs
-    | list{} => b
-    | list{a} => list{f(a), ...b}
-    | a =>
-      O.fmap(
-        concat'(b),
-        O.bind(init(a), x =>
-          O.fmap(F.flip(append, x), O.fmap(fmap(f), O.fmap(singleton, last(a))))
-        ),
-      ) |> O.default(xs)
-    }
-  }
-
-  let without = (exclude, xs) => reject(x => contains(x, exclude), xs)
-  let update = (x, i, xs) => adjust(F.always(x), i, xs)
-  let iter = List.iter
-
-  let findIndex = {
-    let rec loop = (pred, xs, i) =>
-      switch xs {
-      | list{} => None
-      | list{a, ...b} => pred(a) ? Some(i) : loop(pred, b, i + 1)
-      }
-    (pred, xs) => loop(pred, xs, 0)
-  }
-
-  let headSafe = Belt.List.head
-  let tailSafe = Belt.List.tail
-  let headExn = Belt.List.headExn
-  let tailExn = Belt.List.tailExn
-  let zip = Belt.List.zip
-
-  let combinations2: list<'a> => list<('a, 'a)> = xs => {
-    let rec loop: ('a, list<'a>) => list<('a, 'a)> = (x', xs') => {
-      let n = length(xs')
-      if n == 0 {
-        list{}
-      } else {
-        let combs = fmap(y => (x', y), xs')
-        let hd = headExn(xs')
-        let tl = tailExn(xs')
-        concat(list{combs, loop(hd, tl)})
-      }
-    }
-    switch (headSafe(xs), tailSafe(xs)) {
-    | (Some(x'), Some(xs')) => loop(x', xs')
-    | (_, _) => list{}
-    }
-  }
-}
-
-/* A for Array */
-module A = {
-  let fmap = Array.map
-  let fmapi = Array.mapi
-  let to_list = Array.to_list
-  let of_list = Array.of_list
-  let length = Array.length
-  let append = Array.append
-  // let empty = [||];
-  let unsafe_get = Array.unsafe_get
-  let get = Belt.Array.get
-  let getBy = Belt.Array.getBy
-  let getIndexBy = Belt.Array.getIndexBy
-  let last = a => get(a, length(a) - 1)
-  let first = get(_, 0)
-  let hasBy = (r, fn) => Belt.Array.getBy(r, fn) |> O.isSome
-  let fold_left = Array.fold_left
-  let fold_right = Array.fold_right
-  let concat = Belt.Array.concat
-  let concatMany = Belt.Array.concatMany
-  let keepMap = Belt.Array.keepMap
-  let slice = Belt.Array.slice
-  let init = Array.init
-  let reduce = Belt.Array.reduce
-  let reduceReverse = Belt.Array.reduceReverse
-  let reducei = Belt.Array.reduceWithIndex
-  let some = Belt.Array.some
-  let isEmpty = r => length(r) < 1
-  let stableSortBy = Belt.SortArray.stableSortBy
-  let toNoneIfEmpty = r => isEmpty(r) ? None : Some(r)
-  let toRanges = (a: array<'a>) =>
-    switch a |> Belt.Array.length {
-    | 0
-    | 1 =>
-      Belt.Result.Error("Must be at least 2 elements")
-    | n =>
-      Belt.Array.makeBy(n - 1, r => r)
-      |> Belt.Array.map(_, index => (
-        Belt.Array.getUnsafe(a, index),
-        Belt.Array.getUnsafe(a, index + 1),
-      ))
-      |> (x => Ok(x))
-    }
-
-  let getByFmap = (a, fn, boolCondition) => {
-    let i = ref(0)
-    let finalFunctionValue = ref(None)
-    let length = Belt.Array.length(a)
-
-    while i.contents < length && finalFunctionValue.contents == None {
-      let itemWithFnApplied = Belt.Array.getUnsafe(a, i.contents) |> fn
-      if boolCondition(itemWithFnApplied) {
-        finalFunctionValue := Some(itemWithFnApplied)
-      }
-      i := i.contents + 1
-    }
-
-    finalFunctionValue.contents
-  }
-
-  let tail = Belt.Array.sliceToEnd(_, 1)
-
-  let zip = Belt.Array.zip
-  let unzip = Belt.Array.unzip
-  let zip3 = (a, b, c) =>
-    Belt.Array.zip(a, b)->Belt.Array.zip(c)->Belt.Array.map((((v1, v2), v3)) => (v1, v2, v3))
-  // This zips while taking the longest elements of each array.
-  let zipMaxLength = (array1, array2) => {
-    let maxLength = Int.max(length(array1), length(array2))
-    let result = maxLength |> Belt.Array.makeUninitializedUnsafe
-    for i in 0 to maxLength - 1 {
-      Belt.Array.set(result, i, (get(array1, i), get(array2, i))) |> ignore
-    }
-    result
-  }
-
-  let asList = (f: list<'a> => list<'a>, r: array<'a>) => r |> to_list |> f |> of_list
-  /* TODO: Is there a better way of doing this? */
-  let uniq = r => asList(L.uniq, r)
-
-  //intersperse([1,2,3], [10,11,12]) => [1,10,2,11,3,12]
-  let intersperse = (a: array<'a>, b: array<'a>) => {
-    let items: ref<array<'a>> = ref([])
-
-    Belt.Array.forEachWithIndex(a, (i, item) =>
-      switch Belt.Array.get(b, i) {
-      | Some(r) => items := append(items.contents, [item, r])
-      | None => items := append(items.contents, [item])
-      }
-    )
-    items.contents
-  }
-
-  // This is like map, but
-  //accumulate((a,b) => a + b, [1,2,3]) => [1, 3, 5]
-  let accumulate = (fn: ('a, 'a) => 'a, items: array<'a>) => {
-    let length = items |> length
-    let empty = Belt.Array.make(length, items |> unsafe_get(_, 0))
-    Belt.Array.forEachWithIndex(items, (index, element) => {
-      let item = switch index {
-      | 0 => element
-      | index => fn(element, unsafe_get(empty, index - 1))
-      }
-      let _ = Belt.Array.set(empty, index, item)
-    })
-    empty
-  }
-
-  // @todo: Is -1 still the indicator that this is false (as is true with
-  // @todo: js findIndex)? Wasn't sure.
-  let findIndex = (e, i) =>
-    Js.Array.findIndex(e, i) |> (
-      r =>
-        switch r {
-        | -1 => None
-        | r => Some(r)
-        }
-    )
-  let filter = Js.Array.filter
-  let joinWith = Js.Array.joinWith
-  let transpose = (xs: array<array<'a>>): array<array<'a>> => {
-    let arr: array<array<'a>> = []
-    for i in 0 to length(xs) - 1 {
-      for j in 0 to length(xs[i]) - 1 {
-        if Js.Array.length(arr) <= j {
-          ignore(Js.Array.push([xs[i][j]], arr))
-        } else {
-          ignore(Js.Array.push(xs[i][j], arr[j]))
-        }
-      }
-    }
-    arr
-  }
-
-  let all = (p: 'a => bool, xs: array<'a>): bool => length(filter(p, xs)) == length(xs)
-  let any = (p: 'a => bool, xs: array<'a>): bool => length(filter(p, xs)) > 0
-
-  module O = {
-    let concatSomes = (optionals: array<option<'a>>): array<'a> =>
-      optionals
-      |> Js.Array.filter(O.isSome)
-      |> Js.Array.map(O.toExn("Warning: This should not have happened"))
-    let defaultEmpty = (o: option<array<'a>>): array<'a> =>
-      switch o {
-      | Some(o) => o
-      | None => []
-      }
-    // REturns `None` there are no non-`None` elements
-    let rec arrSomeToSomeArr = (optionals: array<option<'a>>): option<array<'a>> => {
-      let optionals' = optionals->Belt.List.fromArray
-      switch optionals' {
-      | list{} => []->Some
-      | list{x, ...xs} =>
-        switch x {
-        | Some(_) => xs->Belt.List.toArray->arrSomeToSomeArr
-        | None => None
-        }
-      }
-    }
-    let firstSome = x => Belt.Array.getBy(x, O.isSome)
-
-    let firstSomeFn = (r: array<unit => option<'a>>): option<'a> =>
-      O.flatten(getByFmap(r, l => l(), O.isSome))
-
-    let firstSomeFnWithDefault = (r, default) => firstSomeFn(r)->O2.default(default)
-
-    let openIfAllSome = (optionals: array<option<'a>>): option<array<'a>> => {
-      if all(O.isSome, optionals) {
-        Some(optionals |> fmap(O.toExn("Warning: This should not have happened")))
-      } else {
-        None
-      }
-    }
-  }
-
-  module R = {
-    let firstErrorOrOpen = (results: array<Belt.Result.t<'a, 'b>>): Belt.Result.t<
-      array<'a>,
-      'b,
-    > => {
-      let bringErrorUp = switch results |> Belt.Array.getBy(_, Belt.Result.isError) {
-      | Some(Belt.Result.Error(err)) => Belt.Result.Error(err)
-      | Some(Belt.Result.Ok(_)) => Belt.Result.Ok(results)
-      | None => Belt.Result.Ok(results)
-      }
-      let forceOpen = (r: array<Belt.Result.t<'a, 'b>>): array<'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
-
-    let forM = (x: array<'a>, fn: 'a => result<'b, 'c>): result<array<'b>, 'c> =>
-      firstErrorOrOpen(fmap(fn, x))
-
-    let foldM = (fn: ('c, 'a) => result<'b, 'e>, init: 'c, x: array<'a>): result<'c, 'e> => {
-      let acc = ref(init)
-      let final = ref(Ok())
-      let break = ref(false)
-      let i = ref(0)
-
-      while break.contents != true && i.contents < length(x) {
-        switch fn(acc.contents, x[i.contents]) {
-        | Ok(r) => acc := r
-        | Error(err) => {
-            final := Error(err)
-            break := true
-          }
-        }
-        i := i.contents + 1
-      }
-      switch final.contents {
-      | Ok(_) => Ok(acc.contents)
-      | Error(err) => Error(err)
-      }
-    }
-  }
-
-  module Floats = {
-    type t = array<float>
-    let mean = Jstat.mean
-    let geomean = Jstat.geomean
-    let mode = Jstat.mode
-    let variance = Jstat.variance
-    let stdev = Jstat.stdev
-    let sum = Jstat.sum
-    let product = Jstat.product
-    let random = Js.Math.random_int
-
-    let floatCompare: (float, float) => int = compare
-    let sort = t => {
-      let r = t
-      r |> Array.fast_sort(floatCompare)
-      r
-    }
-
-    let getNonFinite = (t: t) => Belt.Array.getBy(t, r => !Js.Float.isFinite(r))
-    let getBelowZero = (t: t) => Belt.Array.getBy(t, r => r < 0.0)
-
-    let isSorted = (t: t): bool =>
-      if Array.length(t) < 1 {
-        true
-      } else {
-        reduce(zip(t, tail(t)), true, (acc, (first, second)) => acc && first < second)
-      }
-
-    //Passing true for the exclusive parameter excludes both endpoints of the range.
-    //https://jstat.github.io/all.html
-    let percentile = (a, b) => Jstat.percentile(a, b, false)
-
-    // Gives an array with all the differences between values
-    // diff([1,5,3,7]) = [4,-2,4]
-    let diff = (t: t): array<float> =>
-      Belt.Array.zipBy(t, Belt.Array.sliceToEnd(t, 1), (left, right) => right -. left)
-
-    let cumSum = (t: t): array<float> => accumulate((a, b) => a +. b, t)
-    let cumProd = (t: t): array<float> => accumulate((a, b) => a *. b, t)
-
-    exception RangeError(string)
-    let range = (min: float, max: float, n: int): array<float> =>
-      switch n {
-      | 0 => []
-      | 1 => [min]
-      | 2 => [min, max]
-      | _ if min == max => Belt.Array.make(n, min)
-      | _ if n < 0 => raise(RangeError("n must be greater than 0"))
-      | _ if min > max => raise(RangeError("Min value is less then max value"))
-      | _ =>
-        let diff = (max -. min) /. Belt.Float.fromInt(n - 1)
-        Belt.Array.makeBy(n, i => min +. Belt.Float.fromInt(i) *. diff)
-      }
-
-    let min = Js.Math.minMany_float
-    let max = Js.Math.maxMany_float
-
-    module Sorted = {
-      let min = first
-      let max = last
-      let range = (~min=min, ~max=max, a) =>
-        switch (min(a), max(a)) {
-        | (Some(min), Some(max)) => Some(max -. min)
-        | _ => None
-        }
-
-      let binarySearchFirstElementGreaterIndex = (ar: array<'a>, el: 'a) => {
-        let el = Belt.SortArray.binarySearchBy(ar, el, floatCompare)
-        let el = el < 0 ? el * -1 - 1 : el
-        switch el {
-        | e if e >= length(ar) => #overMax
-        | e if e == 0 => #underMin
-        | e => #firstHigher(e)
-        }
-      }
-
-      let concat = (t1: array<'a>, t2: array<'a>) => Belt.Array.concat(t1, t2)->sort
-
-      let concatMany = (t1: array<array<'a>>) => Belt.Array.concatMany(t1)->sort
-
-      let makeIncrementalUp = (a, b) =>
-        Array.make(b - a + 1, a) |> Array.mapi((i, c) => c + i) |> Belt.Array.map(_, float_of_int)
-
-      let makeIncrementalDown = (a, b) =>
-        Array.make(a - b + 1, a) |> Array.mapi((i, c) => c - i) |> Belt.Array.map(_, float_of_int)
-
-      /*
-      This function goes through a sorted array and divides it into two different clusters:
-      continuous samples and discrete samples. The discrete samples are stored in a mutable map.
-      Samples are thought to be discrete if they have any duplicates.
- */
-      let _splitContinuousAndDiscreteForDuplicates = (sortedArray: array<float>) => {
-        let continuous: array<float> = []
-        let discrete = FloatFloatMap.empty()
-        Belt.Array.forEachWithIndex(sortedArray, (index, element) => {
-          let maxIndex = (sortedArray |> Array.length) - 1
-          let possiblySimilarElements = switch index {
-          | 0 => [index + 1]
-          | n if n == maxIndex => [index - 1]
-          | _ => [index - 1, index + 1]
-          } |> Belt.Array.map(_, r => sortedArray[r])
-          let hasSimilarElement = Belt.Array.some(possiblySimilarElements, r => r == element)
-          hasSimilarElement
-            ? FloatFloatMap.increment(element, discrete)
-            : {
-                let _ = Js.Array.push(element, continuous)
-              }
-
-          ()
-        })
-
-        (continuous, discrete)
-      }
-
-      /*
-      This function works very similarly to splitContinuousAndDiscreteForDuplicates. The one major difference
-      is that you can specify a minDiscreteWeight.  If the min discreet weight is 4, that would mean that
-      at least four elements needed from a specific value for that to be kept as discrete. This is important
-      because in some cases, we can expect that some common elements will be generated by regular operations.
-      The final continous array will be sorted.
- */
-      let splitContinuousAndDiscreteForMinWeight = (
-        sortedArray: array<float>,
-        ~minDiscreteWeight: int,
-      ) => {
-        let (continuous, discrete) = _splitContinuousAndDiscreteForDuplicates(sortedArray)
-        let keepFn = v => Belt.Float.toInt(v) >= minDiscreteWeight
-        let (discreteToKeep, discreteToIntegrate) = FloatFloatMap.partition(
-          ((_, v)) => keepFn(v),
-          discrete,
-        )
-        let newContinousSamples =
-          discreteToIntegrate->FloatFloatMap.toArray
-          |> fmap(((k, v)) => Belt.Array.makeBy(Belt.Float.toInt(v), _ => k))
-          |> Belt.Array.concatMany
-        let newContinuous = concat(continuous, newContinousSamples)
-        newContinuous |> Array.fast_sort(floatCompare)
-        (newContinuous, discreteToKeep)
-      }
-    }
-  }
-  module Sorted = Floats.Sorted
-}
-
-module A2 = {
-  let fmap = (a, b) => A.fmap(b, a)
-  let fmapi = (a, b) => A.fmapi(b, a)
-  let joinWith = (a, b) => A.joinWith(b, a)
-  let filter = (a, b) => A.filter(b, a)
-}
-
-module JsArray = {
-  let concatSomes = (optionals: Js.Array.t<option<'a>>): Js.Array.t<'a> =>
-    optionals
-    |> Js.Array.filter(O.isSome)
-    |> Js.Array.map(O.toExn("Warning: This should not have happened"))
-  let filter = Js.Array.filter
-}
-
-module Dict = {
-  type t<'a> = Js.Dict.t<'a>
-  let get = Js.Dict.get
-  let keys = Js.Dict.keys
-  let fromArray = Js.Dict.fromArray
-  let toArray = Js.Dict.entries
-  let concat = (a, b) => A.concat(toArray(a), toArray(b))->fromArray
-  let concatMany = ts => ts->A2.fmap(toArray)->A.concatMany->fromArray
-}

packages/squiggle-lang/src/rescript/Utility/E/E_A.res

@@ -0,0 +1,360 @@
+/* A for Array */
+// module O = E_O
+module Int = E_Int
+module L = E_L
+module FloatFloatMap = E_FloatFloatMap
+
+let fmap = Array.map
+let fmapi = Array.mapi
+let to_list = Array.to_list
+let of_list = Array.of_list
+let length = Array.length
+let append = Array.append
+// let empty = [||];
+let unsafe_get = Array.unsafe_get
+let get = Belt.Array.get
+let getBy = Belt.Array.getBy
+let getIndexBy = Belt.Array.getIndexBy
+let last = a => get(a, length(a) - 1)
+let first = get(_, 0)
+let hasBy = (r, fn) => Belt.Array.getBy(r, fn) |> E_O.isSome
+let fold_left = Array.fold_left
+let fold_right = Array.fold_right
+let concat = Belt.Array.concat
+let concatMany = Belt.Array.concatMany
+let keepMap = Belt.Array.keepMap
+let slice = Belt.Array.slice
+let init = Array.init
+let reduce = Belt.Array.reduce
+let reduceReverse = Belt.Array.reduceReverse
+let reducei = Belt.Array.reduceWithIndex
+let some = Belt.Array.some
+let isEmpty = r => length(r) < 1
+let stableSortBy = Belt.SortArray.stableSortBy
+let toNoneIfEmpty = r => isEmpty(r) ? None : Some(r)
+let toRanges = (a: array<'a>) =>
+  switch a |> Belt.Array.length {
+  | 0
+  | 1 =>
+    Belt.Result.Error("Must be at least 2 elements")
+  | n =>
+    Belt.Array.makeBy(n - 1, r => r)
+    |> Belt.Array.map(_, index => (
+      Belt.Array.getUnsafe(a, index),
+      Belt.Array.getUnsafe(a, index + 1),
+    ))
+    |> (x => Ok(x))
+  }
+
+let getByFmap = (a, fn, boolCondition) => {
+  let i = ref(0)
+  let finalFunctionValue = ref(None)
+  let length = Belt.Array.length(a)
+
+  while i.contents < length && finalFunctionValue.contents == None {
+    let itemWithFnApplied = Belt.Array.getUnsafe(a, i.contents) |> fn
+    if boolCondition(itemWithFnApplied) {
+      finalFunctionValue := Some(itemWithFnApplied)
+    }
+    i := i.contents + 1
+  }
+
+  finalFunctionValue.contents
+}
+
+let tail = Belt.Array.sliceToEnd(_, 1)
+
+let zip = Belt.Array.zip
+let unzip = Belt.Array.unzip
+let zip3 = (a, b, c) =>
+  Belt.Array.zip(a, b)->Belt.Array.zip(c)->Belt.Array.map((((v1, v2), v3)) => (v1, v2, v3))
+// This zips while taking the longest elements of each array.
+let zipMaxLength = (array1, array2) => {
+  let maxLength = Int.max(length(array1), length(array2))
+  let result = maxLength |> Belt.Array.makeUninitializedUnsafe
+  for i in 0 to maxLength - 1 {
+    Belt.Array.set(result, i, (get(array1, i), get(array2, i))) |> ignore
+  }
+  result
+}
+
+let asList = (f: list<'a> => list<'a>, r: array<'a>) => r |> to_list |> f |> of_list
+/* TODO: Is there a better way of doing this? */
+let uniq = r => asList(L.uniq, r)
+
+//intersperse([1,2,3], [10,11,12]) => [1,10,2,11,3,12]
+let intersperse = (a: array<'a>, b: array<'a>) => {
+  let items: ref<array<'a>> = ref([])
+
+  Belt.Array.forEachWithIndex(a, (i, item) =>
+    switch Belt.Array.get(b, i) {
+    | Some(r) => items := append(items.contents, [item, r])
+    | None => items := append(items.contents, [item])
+    }
+  )
+  items.contents
+}
+
+// This is like map, but
+//accumulate((a,b) => a + b, [1,2,3]) => [1, 3, 5]
+let accumulate = (fn: ('a, 'a) => 'a, items: array<'a>) => {
+  let length = items |> length
+  let empty = Belt.Array.make(length, items |> unsafe_get(_, 0))
+  Belt.Array.forEachWithIndex(items, (index, element) => {
+    let item = switch index {
+    | 0 => element
+    | index => fn(element, unsafe_get(empty, index - 1))
+    }
+    let _ = Belt.Array.set(empty, index, item)
+  })
+  empty
+}
+
+// @todo: Is -1 still the indicator that this is false (as is true with
+// @todo: js findIndex)? Wasn't sure.
+let findIndex = (e, i) =>
+  Js.Array.findIndex(e, i) |> (
+    r =>
+      switch r {
+      | -1 => None
+      | r => Some(r)
+      }
+  )
+let filter = Js.Array.filter
+let joinWith = Js.Array.joinWith
+let transpose = (xs: array<array<'a>>): array<array<'a>> => {
+  let arr: array<array<'a>> = []
+  for i in 0 to length(xs) - 1 {
+    for j in 0 to length(xs[i]) - 1 {
+      if Js.Array.length(arr) <= j {
+        ignore(Js.Array.push([xs[i][j]], arr))
+      } else {
+        ignore(Js.Array.push(xs[i][j], arr[j]))
+      }
+    }
+  }
+  arr
+}
+
+let all = (p: 'a => bool, xs: array<'a>): bool => length(filter(p, xs)) == length(xs)
+let any = (p: 'a => bool, xs: array<'a>): bool => length(filter(p, xs)) > 0
+
+module O = {
+  let concatSomes = (optionals: array<option<'a>>): array<'a> =>
+    optionals
+    |> Js.Array.filter(E_O.isSome)
+    |> Js.Array.map(E_O.toExn("Warning: This should not have happened"))
+  let defaultEmpty = (o: option<array<'a>>): array<'a> =>
+    switch o {
+    | Some(o) => o
+    | None => []
+    }
+  // REturns `None` there are no non-`None` elements
+  let rec arrSomeToSomeArr = (optionals: array<option<'a>>): option<array<'a>> => {
+    let optionals' = optionals->Belt.List.fromArray
+    switch optionals' {
+    | list{} => []->Some
+    | list{x, ...xs} =>
+      switch x {
+      | Some(_) => xs->Belt.List.toArray->arrSomeToSomeArr
+      | None => None
+      }
+    }
+  }
+  let firstSome = x => Belt.Array.getBy(x, E_O.isSome)
+
+  let firstSomeFn = (r: array<unit => option<'a>>): option<'a> =>
+    E_O.flatten(getByFmap(r, l => l(), E_O.isSome))
+
+  let firstSomeFnWithDefault = (r, default) => firstSomeFn(r)->E_O2.default(default)
+
+  let openIfAllSome = (optionals: array<option<'a>>): option<array<'a>> => {
+    if all(E_O.isSome, optionals) {
+      Some(optionals |> fmap(E_O.toExn("Warning: This should not have happened")))
+    } else {
+      None
+    }
+  }
+}
+
+module R = {
+  let firstErrorOrOpen = (results: array<Belt.Result.t<'a, 'b>>): Belt.Result.t<array<'a>, 'b> => {
+    let bringErrorUp = switch results |> Belt.Array.getBy(_, Belt.Result.isError) {
+    | Some(Belt.Result.Error(err)) => Belt.Result.Error(err)
+    | Some(Belt.Result.Ok(_)) => Belt.Result.Ok(results)
+    | None => Belt.Result.Ok(results)
+    }
+    let forceOpen = (r: array<Belt.Result.t<'a, 'b>>): array<'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(E_R.toOption, x)->O.concatSomes
+
+  let forM = (x: array<'a>, fn: 'a => result<'b, 'c>): result<array<'b>, 'c> =>
+    firstErrorOrOpen(fmap(fn, x))
+
+  let foldM = (fn: ('c, 'a) => result<'b, 'e>, init: 'c, x: array<'a>): result<'c, 'e> => {
+    let acc = ref(init)
+    let final = ref(Ok())
+    let break = ref(false)
+    let i = ref(0)
+
+    while break.contents != true && i.contents < length(x) {
+      switch fn(acc.contents, x[i.contents]) {
+      | Ok(r) => acc := r
+      | Error(err) => {
+          final := Error(err)
+          break := true
+        }
+      }
+      i := i.contents + 1
+    }
+    switch final.contents {
+    | Ok(_) => Ok(acc.contents)
+    | Error(err) => Error(err)
+    }
+  }
+}
+
+module Floats = {
+  type t = array<float>
+  let mean = Jstat.mean
+  let geomean = Jstat.geomean
+  let mode = Jstat.mode
+  let variance = Jstat.variance
+  let stdev = Jstat.stdev
+  let sum = Jstat.sum
+  let product = Jstat.product
+  let random = Js.Math.random_int
+
+  let floatCompare: (float, float) => int = compare
+  let sort = t => {
+    let r = t
+    r |> Array.fast_sort(floatCompare)
+    r
+  }
+
+  let getNonFinite = (t: t) => Belt.Array.getBy(t, r => !Js.Float.isFinite(r))
+  let getBelowZero = (t: t) => Belt.Array.getBy(t, r => r < 0.0)
+
+  let isSorted = (t: t): bool =>
+    if Array.length(t) < 1 {
+      true
+    } else {
+      reduce(zip(t, tail(t)), true, (acc, (first, second)) => acc && first < second)
+    }
+
+  //Passing true for the exclusive parameter excludes both endpoints of the range.
+  //https://jstat.github.io/all.html
+  let percentile = (a, b) => Jstat.percentile(a, b, false)
+
+  // Gives an array with all the differences between values
+  // diff([1,5,3,7]) = [4,-2,4]
+  let diff = (t: t): array<float> =>
+    Belt.Array.zipBy(t, Belt.Array.sliceToEnd(t, 1), (left, right) => right -. left)
+
+  let cumSum = (t: t): array<float> => accumulate((a, b) => a +. b, t)
+  let cumProd = (t: t): array<float> => accumulate((a, b) => a *. b, t)
+
+  exception RangeError(string)
+  let range = (min: float, max: float, n: int): array<float> =>
+    switch n {
+    | 0 => []
+    | 1 => [min]
+    | 2 => [min, max]
+    | _ if min == max => Belt.Array.make(n, min)
+    | _ if n < 0 => raise(RangeError("n must be greater than 0"))
+    | _ if min > max => raise(RangeError("Min value is less then max value"))
+    | _ =>
+      let diff = (max -. min) /. Belt.Float.fromInt(n - 1)
+      Belt.Array.makeBy(n, i => min +. Belt.Float.fromInt(i) *. diff)
+    }
+
+  let min = Js.Math.minMany_float
+  let max = Js.Math.maxMany_float
+
+  module Sorted = {
+    let min = first
+    let max = last
+    let range = (~min=min, ~max=max, a) =>
+      switch (min(a), max(a)) {
+      | (Some(min), Some(max)) => Some(max -. min)
+      | _ => None
+      }
+
+    let binarySearchFirstElementGreaterIndex = (ar: array<'a>, el: 'a) => {
+      let el = Belt.SortArray.binarySearchBy(ar, el, floatCompare)
+      let el = el < 0 ? el * -1 - 1 : el
+      switch el {
+      | e if e >= length(ar) => #overMax
+      | e if e == 0 => #underMin
+      | e => #firstHigher(e)
+      }
+    }
+
+    let concat = (t1: array<'a>, t2: array<'a>) => Belt.Array.concat(t1, t2)->sort
+
+    let concatMany = (t1: array<array<'a>>) => Belt.Array.concatMany(t1)->sort
+
+    let makeIncrementalUp = (a, b) =>
+      Array.make(b - a + 1, a) |> Array.mapi((i, c) => c + i) |> Belt.Array.map(_, float_of_int)
+
+    let makeIncrementalDown = (a, b) =>
+      Array.make(a - b + 1, a) |> Array.mapi((i, c) => c - i) |> Belt.Array.map(_, float_of_int)
+
+    /*
+      This function goes through a sorted array and divides it into two different clusters:
+      continuous samples and discrete samples. The discrete samples are stored in a mutable map.
+      Samples are thought to be discrete if they have any duplicates.
+ */
+    let _splitContinuousAndDiscreteForDuplicates = (sortedArray: array<float>) => {
+      let continuous: array<float> = []
+      let discrete = FloatFloatMap.empty()
+      Belt.Array.forEachWithIndex(sortedArray, (index, element) => {
+        let maxIndex = (sortedArray |> Array.length) - 1
+        let possiblySimilarElements = switch index {
+        | 0 => [index + 1]
+        | n if n == maxIndex => [index - 1]
+        | _ => [index - 1, index + 1]
+        } |> Belt.Array.map(_, r => sortedArray[r])
+        let hasSimilarElement = Belt.Array.some(possiblySimilarElements, r => r == element)
+        hasSimilarElement
+          ? FloatFloatMap.increment(element, discrete)
+          : {
+              let _ = Js.Array.push(element, continuous)
+            }
+
+        ()
+      })
+
+      (continuous, discrete)
+    }
+
+    /*
+      This function works very similarly to splitContinuousAndDiscreteForDuplicates. The one major difference
+      is that you can specify a minDiscreteWeight.  If the min discreet weight is 4, that would mean that
+      at least four elements needed from a specific value for that to be kept as discrete. This is important
+      because in some cases, we can expect that some common elements will be generated by regular operations.
+      The final continous array will be sorted.
+ */
+    let splitContinuousAndDiscreteForMinWeight = (
+      sortedArray: array<float>,
+      ~minDiscreteWeight: int,
+    ) => {
+      let (continuous, discrete) = _splitContinuousAndDiscreteForDuplicates(sortedArray)
+      let keepFn = v => Belt.Float.toInt(v) >= minDiscreteWeight
+      let (discreteToKeep, discreteToIntegrate) = FloatFloatMap.partition(
+        ((_, v)) => keepFn(v),
+        discrete,
+      )
+      let newContinousSamples =
+        discreteToIntegrate->FloatFloatMap.toArray
+        |> fmap(((k, v)) => Belt.Array.makeBy(Belt.Float.toInt(v), _ => k))
+        |> Belt.Array.concatMany
+      let newContinuous = concat(continuous, newContinousSamples)
+      newContinuous |> Array.fast_sort(floatCompare)
+      (newContinuous, discreteToKeep)
+    }
+  }
+}
+module Sorted = Floats.Sorted

packages/squiggle-lang/src/rescript/Utility/E/E_A2.res

@@ -0,0 +1,5 @@
+module A = E_A
+let fmap = (a, b) => A.fmap(b, a)
+let fmapi = (a, b) => A.fmapi(b, a)
+let joinWith = (a, b) => A.joinWith(b, a)
+let filter = (a, b) => A.filter(b, a)

packages/squiggle-lang/src/rescript/Utility/E/E_B.res

@@ -0,0 +1,11 @@
+type t = bool
+let toString = (t: t) => t ? "TRUE" : "FALSE"
+let fromString = str => str == "TRUE" ? true : false
+
+module O = {
+  let toBool = opt =>
+    switch opt {
+    | Some(true) => true
+    | _ => false
+    }
+}

packages/squiggle-lang/src/rescript/Utility/E/E_Dict.res

@@ -0,0 +1,10 @@
+module A = E_A
+module A2 = E_A2
+
+type t<'a> = Js.Dict.t<'a>
+let get = Js.Dict.get
+let keys = Js.Dict.keys
+let fromArray = Js.Dict.fromArray
+let toArray = Js.Dict.entries
+let concat = (a, b) => A.concat(toArray(a), toArray(b))->fromArray
+let concatMany = ts => ts->A2.fmap(toArray)->A.concatMany->fromArray

packages/squiggle-lang/src/rescript/Utility/E/E_F.res

@@ -0,0 +1,20 @@
+/* Functions */
+let pipe = (f, g, x) => g(f(x))
+let compose = (f, g, x) => f(g(x))
+let flip = (f, a, b) => f(b, a)
+let always = (x, _y) => x
+
+let apply = (a, e) => a |> e
+
+let flatten2Callbacks = (fn1, fn2, fnlast) =>
+  fn1(response1 => fn2(response2 => fnlast(response1, response2)))
+
+let flatten3Callbacks = (fn1, fn2, fn3, fnlast) =>
+  fn1(response1 => fn2(response2 => fn3(response3 => fnlast(response1, response2, response3))))
+
+let flatten4Callbacks = (fn1, fn2, fn3, fn4, fnlast) =>
+  fn1(response1 =>
+    fn2(response2 =>
+      fn3(response3 => fn4(response4 => fnlast(response1, response2, response3, response4)))
+    )
+  )

packages/squiggle-lang/src/rescript/Utility/E/E_Float.res

@@ -0,0 +1,6 @@
+let with2DigitsPrecision = Js.Float.toPrecisionWithPrecision(_, ~digits=2)
+let with3DigitsPrecision = Js.Float.toPrecisionWithPrecision(_, ~digits=3)
+let toFixed = Js.Float.toFixed
+let toString = Js.Float.toString
+let isFinite = Js.Float.isFinite
+let toInt = Belt.Float.toInt

packages/squiggle-lang/src/rescript/Utility/E/E_FloatFloatMap.res

@@ -0,0 +1,24 @@
+module Id = Belt.Id.MakeComparable({
+  type t = float
+  let cmp: (float, float) => int = Pervasives.compare
+})
+
+type t = Belt.MutableMap.t<Id.t, float, Id.identity>
+
+let fromArray = (ar: array<(float, float)>) => Belt.MutableMap.fromArray(ar, ~id=module(Id))
+let toArray = (t: t): array<(float, float)> => Belt.MutableMap.toArray(t)
+let empty = () => Belt.MutableMap.make(~id=module(Id))
+let increment = (el, t: t) =>
+  Belt.MutableMap.update(t, el, x =>
+    switch x {
+    | Some(n) => Some(n +. 1.0)
+    | None => Some(1.0)
+    }
+  )
+
+let get = (el, t: t) => Belt.MutableMap.get(t, el)
+let fmap = (fn, t: t) => Belt.MutableMap.map(t, fn)
+let partition = (fn, t: t) => {
+  let (match, noMatch) = Belt.Array.partition(toArray(t), fn)
+  (fromArray(match), fromArray(noMatch))
+}

packages/squiggle-lang/src/rescript/Utility/E/E_I.res

@@ -0,0 +1,4 @@
+let increment = n => n + 1
+let decrement = n => n - 1
+let toString = Js.Int.toString
+let toFloat = Js.Int.toFloat

packages/squiggle-lang/src/rescript/Utility/E/E_Int.res

@@ -0,0 +1,2 @@
+let max = (i1: int, i2: int) => i1 > i2 ? i1 : i2
+let random = (~min, ~max) => Js.Math.random_int(min, max)

packages/squiggle-lang/src/rescript/Utility/E/E_J.res

@@ -0,0 +1,19 @@
+module F = E_F
+
+let toString = F.pipe(Js.Json.decodeString, E_O.default(""))
+let fromString = Js.Json.string
+let fromNumber = Js.Json.number
+
+module O = {
+  let fromString = (str: string) =>
+    switch str {
+    | "" => None
+    | _ => Some(Js.Json.string(str))
+    }
+
+  let toString = (str: option<'a>) =>
+    switch str {
+    | Some(str) => Some(str |> F.pipe(Js.Json.decodeString, E_O.default("")))
+    | _ => None
+    }
+}

packages/squiggle-lang/src/rescript/Utility/E/E_JsArray.res

@@ -0,0 +1,6 @@
+module O = E_O
+let concatSomes = (optionals: Js.Array.t<option<'a>>): Js.Array.t<'a> =>
+  optionals
+  |> Js.Array.filter(O.isSome)
+  |> Js.Array.map(O.toExn("Warning: This should not have happened"))
+let filter = Js.Array.filter

packages/squiggle-lang/src/rescript/Utility/E/E_JsDate.res

@@ -0,0 +1,4 @@
+let fromString = Js.Date.fromString
+let now = Js.Date.now
+let make = Js.Date.make
+let valueOf = Js.Date.valueOf

packages/squiggle-lang/src/rescript/Utility/E/E_L.res

@@ -0,0 +1,151 @@
+/* List */
+module F = E_F
+module O = E_O
+
+module Util = {
+  let eq = \"=="
+}
+let fmap = List.map
+let get = Belt.List.get
+let toArray = Array.of_list
+let fmapi = List.mapi
+let concat = List.concat
+let concat' = (xs, ys) => List.append(ys, xs)
+
+let rec drop = (i, xs) =>
+  switch (i, xs) {
+  | (_, list{}) => list{}
+  | (i, _) if i <= 0 => xs
+  | (i, list{_, ...b}) => drop(i - 1, b)
+  }
+
+let append = (a, xs) => List.append(xs, list{a})
+let take = {
+  let rec loop = (i, xs, acc) =>
+    switch (i, xs) {
+    | (i, _) if i <= 0 => acc
+    | (_, list{}) => acc
+    | (i, list{a, ...b}) => loop(i - 1, b, append(a, acc))
+    }
+  (i, xs) => loop(i, xs, list{})
+}
+let takeLast = (i, xs) => List.rev(xs) |> take(i) |> List.rev
+
+let splitAt = (i, xs) => (take(i, xs), takeLast(List.length(xs) - i, xs))
+let remove = (i, n, xs) => {
+  let (a, b) = splitAt(i, xs)
+  \"@"(a, drop(n, b))
+}
+
+let find = List.find
+let filter = List.filter
+let for_all = List.for_all
+let exists = List.exists
+let sort = List.sort
+let length = List.length
+
+let filter_opt = xs => {
+  let rec loop = (l, acc) =>
+    switch l {
+    | list{} => acc
+    | list{hd, ...tl} =>
+      switch hd {
+      | None => loop(tl, acc)
+      | Some(x) => loop(tl, list{x, ...acc})
+      }
+    }
+  List.rev(loop(xs, list{}))
+}
+
+let containsWith = f => List.exists(f)
+
+let uniqWithBy = (eq, f, xs) =>
+  List.fold_left(
+    ((acc, tacc), v) =>
+      containsWith(eq(f(v)), tacc) ? (acc, tacc) : (append(v, acc), append(f(v), tacc)),
+    (list{}, list{}),
+    xs,
+  ) |> fst
+
+let uniqBy = (f, xs) => uniqWithBy(Util.eq, f, xs)
+let join = j => List.fold_left((acc, v) => String.length(acc) == 0 ? v : acc ++ (j ++ v), "")
+
+let head = xs =>
+  switch List.hd(xs) {
+  | exception _ => None
+  | a => Some(a)
+  }
+
+let uniq = xs => uniqBy(x => x, xs)
+let flatten = List.flatten
+let last = xs => xs |> List.rev |> head
+let append = List.append
+let getBy = Belt.List.getBy
+let dropLast = (i, xs) => take(List.length(xs) - i, xs)
+let containsWith = f => List.exists(f)
+let contains = x => containsWith(Util.eq(x))
+
+let reject = pred => List.filter(x => !pred(x))
+let tail = xs =>
+  switch List.tl(xs) {
+  | exception _ => None
+  | a => Some(a)
+  }
+
+let init = xs => {
+  O.fmap(List.rev, xs |> List.rev |> tail)
+}
+
+let singleton = (x: 'a): list<'a> => list{x}
+
+let adjust = (f, i, xs) => {
+  let (a, b) = splitAt(i + 1, xs)
+  switch a {
+  | _ if i < 0 => xs
+  | _ if i >= List.length(xs) => xs
+  | list{} => b
+  | list{a} => list{f(a), ...b}
+  | a =>
+    O.fmap(
+      concat'(b),
+      O.bind(init(a), x => O.fmap(F.flip(append, x), O.fmap(fmap(f), O.fmap(singleton, last(a))))),
+    ) |> O.default(xs)
+  }
+}
+
+let without = (exclude, xs) => reject(x => contains(x, exclude), xs)
+let update = (x, i, xs) => adjust(F.always(x), i, xs)
+let iter = List.iter
+
+let findIndex = {
+  let rec loop = (pred, xs, i) =>
+    switch xs {
+    | list{} => None
+    | list{a, ...b} => pred(a) ? Some(i) : loop(pred, b, i + 1)
+    }
+  (pred, xs) => loop(pred, xs, 0)
+}
+
+let headSafe = Belt.List.head
+let tailSafe = Belt.List.tail
+let headExn = Belt.List.headExn
+let tailExn = Belt.List.tailExn
+let zip = Belt.List.zip
+
+let combinations2: list<'a> => list<('a, 'a)> = xs => {
+  let rec loop: ('a, list<'a>) => list<('a, 'a)> = (x', xs') => {
+    let n = length(xs')
+    if n == 0 {
+      list{}
+    } else {
+      let combs = fmap(y => (x', y), xs')
+      let hd = headExn(xs')
+      let tl = tailExn(xs')
+      concat(list{combs, loop(hd, tl)})
+    }
+  }
+  switch (headSafe(xs), tailSafe(xs)) {
+  | (Some(x'), Some(xs')) => loop(x', xs')
+  | (_, _) => list{}
+  }
+}

packages/squiggle-lang/src/rescript/Utility/E/E_O.res

@@ -0,0 +1,99 @@
+let dimap = (sFn, rFn, e) =>
+  switch e {
+  | Some(r) => sFn(r)
+  | None => rFn()
+  }
+()
+let fmap = (f: 'a => 'b, x: option<'a>): option<'b> => {
+  switch x {
+  | None => None
+  | Some(x') => Some(f(x'))
+  }
+}
+let bind = (o, f) =>
+  switch o {
+  | None => None
+  | Some(a) => f(a)
+  }
+let default = (d, o) =>
+  switch o {
+  | None => d
+  | Some(a) => a
+  }
+let defaultFn = (d, o) =>
+  switch o {
+  | None => d()
+  | Some(a) => a
+  }
+let isSome = o =>
+  switch o {
+  | Some(_) => true
+  | _ => false
+  }
+let isNone = o =>
+  switch o {
+  | None => true
+  | _ => false
+  }
+let toExn = (err, o) =>
+  switch o {
+  | None => raise(Failure(err))
+  | Some(a) => a
+  }
+
+let some = a => Some(a)
+let firstSome = (a, b) =>
+  switch a {
+  | None => b
+  | _ => a
+  }
+
+let toExt = toExn
+
+let flatten = o =>
+  switch o {
+  | None => None
+  | Some(x) => x
+  }
+
+let apply = (o, a) =>
+  switch o {
+  | Some(f) => bind(a, b => some(f(b)))
+  | _ => None
+  }
+let flatApply = (fn, b) => apply(fn, Some(b)) |> flatten
+
+let toBool = opt =>
+  switch opt {
+  | Some(_) => true
+  | _ => false
+  }
+
+let ffmap = (fn, r) =>
+  switch r {
+  | Some(sm) => fn(sm)
+  | _ => None
+  }
+
+let toString = opt =>
+  switch opt {
+  | Some(s) => s
+  | _ => ""
+  }
+
+let toResult = (error, e) =>
+  switch e {
+  | Some(r) => Belt.Result.Ok(r)
+  | None => Error(error)
+  }
+
+let compare = (compare, f1: option<float>, f2: option<float>) =>
+  switch (f1, f2) {
+  | (Some(f1), Some(f2)) => Some(compare(f1, f2) ? f1 : f2)
+  | (Some(f1), None) => Some(f1)
+  | (None, Some(f2)) => Some(f2)
+  | (None, None) => None
+  }
+
+let min = compare(\"<")
+let max = compare(\">")

packages/squiggle-lang/src/rescript/Utility/E/E_O2.res

@@ -0,0 +1,7 @@
+module O = E_O
+let default = (a, b) => O.default(b, a)
+let defaultFn = (a, b) => O.defaultFn(b, a)
+let toExn = (a, b) => O.toExn(b, a)
+let fmap = (a, b) => O.fmap(b, a)
+let toResult = (a, b) => O.toResult(b, a)
+let bind = (a, b) => O.bind(b, a)

packages/squiggle-lang/src/rescript/Utility/E/E_R.res

@@ -0,0 +1,94 @@
+/* R for Result */
+
+exception Assertion(string)
+module U = E_U
+
+open Belt.Result
+let result = (okF, errF, r) =>
+  switch r {
+  | Ok(a) => okF(a)
+  | Error(err) => errF(err)
+  }
+let id = e => e |> result(U.id, U.id)
+let isOk = Belt.Result.isOk
+let getError = (r: result<'a, 'b>) =>
+  switch r {
+  | Ok(_) => None
+  | Error(e) => Some(e)
+  }
+let fmap = (f: 'a => 'b, r: result<'a, 'c>): result<'b, 'c> => {
+  switch r {
+  | Ok(r') => Ok(f(r'))
+  | Error(err) => Error(err)
+  }
+}
+let bind = (r, f) =>
+  switch r {
+  | Ok(a) => f(a)
+  | Error(err) => Error(err)
+  }
+let toExn = (msg: string, x: result<'a, 'b>): 'a =>
+  switch x {
+  | Ok(r) => r
+  | Error(_) => raise(Assertion(msg))
+  }
+let toExnFnString = (errorToStringFn, o) =>
+  switch o {
+  | Ok(r) => r
+  | Error(r) => raise(Assertion(errorToStringFn(r)))
+  }
+let default = (default, res: Belt.Result.t<'a, 'b>) =>
+  switch res {
+  | Ok(r) => r
+  | Error(_) => default
+  }
+let merge = (a, b) =>
+  switch (a, b) {
+  | (Error(e), _) => Error(e)
+  | (_, Error(e)) => Error(e)
+  | (Ok(a), Ok(b)) => Ok((a, b))
+  }
+let toOption = (e: Belt.Result.t<'a, 'b>) =>
+  switch e {
+  | Ok(r) => Some(r)
+  | Error(_) => None
+  }
+
+let errorIfCondition = (errorCondition, errorMessage, r) =>
+  errorCondition(r) ? Error(errorMessage) : Ok(r)
+
+let ap = (r, a) =>
+  switch r {
+  | Ok(f) => Ok(f(a))
+  | Error(err) => Error(err)
+  }
+let ap' = (r, a) =>
+  switch r {
+  | Ok(f) => fmap(f, a)
+  | Error(err) => Error(err)
+  }
+
+let liftM2: (('a, 'b) => 'c, result<'a, 'd>, result<'b, 'd>) => result<'c, 'd> = (op, xR, yR) => {
+  ap'(fmap(op, xR), yR)
+}
+
+let liftJoin2: (('a, 'b) => result<'c, 'd>, result<'a, 'd>, result<'b, 'd>) => result<'c, 'd> = (
+  op,
+  xR,
+  yR,
+) => {
+  bind(liftM2(op, xR, yR), x => x)
+}
+
+let fmap2 = (f, r) =>
+  switch r {
+  | Ok(r) => r->Ok
+  | Error(x) => x->f->Error
+  }
+
+//I'm not sure what to call this.
+let unify = (a: result<'a, 'b>, c: 'b => 'a): 'a =>
+  switch a {
+  | Ok(x) => x
+  | Error(x) => c(x)
+  }

packages/squiggle-lang/src/rescript/Utility/E/E_R2.res

@@ -0,0 +1,19 @@
+module R = E_R
+
+let fmap = (a, b) => R.fmap(b, a)
+let bind = (a, b) => R.bind(b, a)
+
+//Converts result type to change error type only
+let errMap = (a: result<'a, 'b>, map: 'b => 'c): result<'a, 'c> =>
+  switch a {
+  | Ok(r) => Ok(r)
+  | Error(e) => Error(map(e))
+  }
+
+let fmap2 = (xR, f) =>
+  switch xR {
+  | Ok(x) => x->Ok
+  | Error(x) => x->f->Error
+  }
+
+let toExn = (a, b) => R.toExn(b, a)

packages/squiggle-lang/src/rescript/Utility/E/E_S.res

@@ -0,0 +1,8 @@
+let safe_fn_of_string = (fn, s: string): option<'a> =>
+  try Some(fn(s)) catch {
+  | _ => None
+  }
+
+let safe_float = float_of_string->safe_fn_of_string
+let safe_int = int_of_string->safe_fn_of_string
+let default = (defaultStr, str) => str == "" ? defaultStr : str

packages/squiggle-lang/src/rescript/Utility/E/E_Tuple2.res

@@ -0,0 +1,9 @@
+let first = (v: ('a, 'b)) => {
+  let (a, _) = v
+  a
+}
+let second = (v: ('a, 'b)) => {
+  let (_, b) = v
+  b
+}
+let toFnCall = (fn, (a1, a2)) => fn(a1, a2)

packages/squiggle-lang/src/rescript/Utility/E/E_Tuple3.res

@@ -0,0 +1 @@
+let toFnCall = (fn, (a1, a2, a3)) => fn(a1, a2, a3)

packages/squiggle-lang/src/rescript/Utility/E/E_U.res

@@ -0,0 +1,4 @@
+/* Utils */
+let isEqual = \"=="
+let toA = a => [a]
+let id = e => e