Reducer: Environment (Give environement to all function dispatches) - closes #169

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

@@ -1,9 +1,17 @@
 module Expression = Reducer.Expression
 module ExpressionValue = ReducerInterface.ExpressionValue
+module ErrorValue = Reducer_ErrorValue
 
 open Jest
 open Expect
 
+let unwrapRecord = rValue =>
+  rValue->Belt.Result.flatMap(value => switch value {
+  | ExpressionValue.EvRecord(aRecord) => Ok(aRecord)
+  | _ => ErrorValue.RETodo("TODO: External bindings must be returned")->Error
+  }
+)
+
 let expectParseToBe = (expr: string, answer: string) =>
   Reducer.parse(expr)->Expression.toStringResult->expect->toBe(answer)
 
@@ -17,7 +25,7 @@ let expectEvalToBe = (expr: string, answer: string) =>
   Reducer.evaluate(expr)->ExpressionValue.toStringResult->expect->toBe(answer)
 
 let expectEvalBindingsToBe = (expr: string, bindings: Reducer.externalBindings, answer: string) =>
-  Reducer.evaluateUsingExternalBindings(expr, bindings)
+  Reducer.evaluateUsingOptions(expr, ~externalBindings=Some(bindings), ~isPartial=None, ~environment=None)
   ->ExpressionValue.toStringResult
   ->expect
   ->toBe(answer)
@@ -27,7 +35,8 @@ let expectEvalPartialBindingsToBe = (
   bindings: Reducer.externalBindings,
   answer: string,
 ) =>
-  Reducer.evaluatePartialUsingExternalBindings(expr, bindings)
+  Reducer.evaluateUsingOptions(expr, ~externalBindings=Some(bindings), ~isPartial=Some(true), ~environment=None)
+  ->unwrapRecord
   ->ExpressionValue.toStringResultRecord
   ->expect
   ->toBe(answer)

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

@@ -5,11 +5,12 @@ module Extra = Reducer_Extra
 module Js = Reducer_Js
 module MathJs = Reducer_MathJs
 
+type environment = ReducerInterface_ExpressionValue.environment
+type errorValue = Reducer_ErrorValue.errorValue
 type expressionValue = ReducerInterface_ExpressionValue.expressionValue
 type externalBindings = ReducerInterface_ExpressionValue.externalBindings
-let evaluate = Expression.eval
-let evaluateUsingExternalBindings = Expression.evalUsingExternalBindings
-let evaluatePartialUsingExternalBindings = Expression.evalPartialUsingExternalBindings
+let evaluate = Expression.evaluate
+let evaluateUsingOptions = Expression.evaluateUsingOptions
 let parse = Expression.parse
 let parseOuter = Expression.parseOuter
 let parsePartial = Expression.parsePartial

packages/squiggle-lang/src/rescript/Reducer/Reducer.resi

@@ -5,22 +5,29 @@ module Extra = Reducer_Extra
 module Js = Reducer_Js
 module MathJs = Reducer_MathJs
 
+@genType 
+type environment = ReducerInterface_ExpressionValue.environment
+@genType 
+type errorValue = Reducer_ErrorValue.errorValue
 @genType 
 type expressionValue = ReducerInterface_ExpressionValue.expressionValue
 @genType 
 type externalBindings = ReducerInterface_ExpressionValue.externalBindings
+
 @genType 
-let evaluate: string => result<expressionValue, Reducer_ErrorValue.errorValue>
-@genType
-let evaluateUsingExternalBindings: (
+let evaluateUsingOptions: (
+  ~environment: option<
+    QuriSquiggleLang.ReducerInterface_ExpressionValue.environment,
+  >,
+  ~externalBindings: option<
+    QuriSquiggleLang.ReducerInterface_ExpressionValue.externalBindings,
+  >,
+  ~isPartial: option<bool>,
   string,
-  externalBindings,
-) => result<expressionValue, Reducer_ErrorValue.errorValue>
+) => result<expressionValue, errorValue>
 @genType 
-let evaluatePartialUsingExternalBindings: (
-  string,
-  externalBindings,
-) => result<externalBindings, Reducer_ErrorValue.errorValue>
-let parse: string => result<Expression.expression, ErrorValue.errorValue>
-let parseOuter: string => result<Expression.expression, ErrorValue.errorValue>
-let parsePartial: string => result<Expression.expression, ErrorValue.errorValue>
+let evaluate: string => result<expressionValue, errorValue>
+
+let parse: string => result<Expression.expression, errorValue>
+let parseOuter: string => result<Expression.expression, errorValue>
+let parsePartial: string => result<Expression.expression, errorValue>

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

@@ -11,7 +11,7 @@ open Reducer_ErrorValue
 
 exception TestRescriptException
 
-let callInternal = (call: functionCall): result<'b, errorValue> => {
+let callInternal = (call: functionCall, _environment): result<'b, errorValue> => {
   let callMathJs = (call: functionCall): result<'b, errorValue> =>
     switch call {
     | ("javascriptraise", [msg]) => Js.Exn.raiseError(toString(msg)) // For Tests
@@ -85,12 +85,12 @@ let callInternal = (call: functionCall): result<'b, errorValue> => {
 /*
   Reducer uses Result monad while reducing expressions
 */
-let dispatch = (call: functionCall): result<expressionValue, errorValue> =>
+let dispatch = (call: functionCall, environment): result<expressionValue, errorValue> =>
   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), callInternal)
+    ExternalLibrary.dispatch((Js.String.make(fn), args), environment, callInternal)
   } catch {
   | Js.Exn.Error(obj) => REJavaScriptExn(Js.Exn.message(obj), Js.Exn.name(obj))->Error
   | _ => RETodo("unhandled rescript exception")->Error

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

@@ -10,10 +10,12 @@ module Result = Belt.Result
 open Reducer_ErrorValue
 
 type expression = ExpressionT.expression
+type environment = ExpressionValue.environment
 
 type reducerFn = (
   expression,
   ExpressionT.bindings,
+  environment,
 ) => result<ExpressionValue.expressionValue, errorValue>
 
 let rec replaceSymbols = (expression: expression, bindings: ExpressionT.bindings): result<
@@ -101,6 +103,7 @@ let rec replaceSymbols = (expression: expression, bindings: ExpressionT.bindings
 let dispatchMacroCall = (
   list: list<expression>,
   bindings: ExpressionT.bindings,
+  environment,
   reduceExpression: reducerFn,
 ): result<expression, 'e> => {
   let doBindStatement = (statement: expression, bindings: ExpressionT.bindings) => {
@@ -114,7 +117,7 @@ let dispatchMacroCall = (
 
         let rNewValue =
           rNewExpressionToReduce->Result.flatMap(newExpressionToReduce =>
-            reduceExpression(newExpressionToReduce, bindings)
+            reduceExpression(newExpressionToReduce, bindings, environment)
           )
 
         let rNewExpression = rNewValue->Result.map(newValue => ExpressionT.EValue(newValue))

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

@@ -8,9 +8,12 @@ module T = Reducer_Expression_T
 
 open Reducer_ErrorValue
 
+type environment = ReducerInterface_ExpressionValue.environment
+type errorValue = Reducer_ErrorValue.errorValue
 type expression = T.expression
-type expressionValue = ExpressionValue.expressionValue
-type internalCode = ExpressionValue.internalCode
+type expressionValue = ReducerInterface_ExpressionValue.expressionValue
+type externalBindings = ReducerInterface_ExpressionValue.externalBindings
+type internalCode = ReducerInterface_ExpressionValue.internalCode
 type t = expression
 
 external castExpressionToInternalCode: expression => internalCode = "%identity"
@@ -57,19 +60,20 @@ let defaultBindings: T.bindings = Belt.Map.String.empty
 /*
   Recursively evaluate/reduce the expression (Lisp AST)
 */
-let rec reduceExpression = (expression: t, bindings: T.bindings): result<expressionValue, 'e> => {
+let rec reduceExpression = (expression: t, bindings: T.bindings, environment: environment): result<expressionValue, 'e> => {
   /*
     Macros are like functions but instead of taking values as parameters,
     they take expressions as parameters and return a new expression.
     Macros are used to define language building blocks. They are like Lisp macros.
  */
-  let doMacroCall = (list: list<t>, bindings: T.bindings): result<t, 'e> =>
-    Reducer_Dispatch_BuiltInMacros.dispatchMacroCall(list, bindings, reduceExpression)
+  let doMacroCall = (list: list<t>, bindings: T.bindings, environment: environment): result<t, 'e> =>
+    Reducer_Dispatch_BuiltInMacros.dispatchMacroCall(list, bindings, environment, reduceExpression)
 
   let applyParametersToLambda = (
     internal: internalCode,
     parameters: array<string>,
     args: list<expressionValue>,
+    environment
   ): result<expressionValue, 'e> => {
     let expr = castInternalCodeToExpression(internal)
     let parameterList = parameters->Belt.List.fromArray
@@ -81,22 +85,22 @@ let rec reduceExpression = (expression: t, bindings: T.bindings): result<express
       "$$bindExpression",
       list{Builder.passToFunction("$$bindings", list{}), expr},
     )
-    reduceExpression(newExpression, bindings)
+    reduceExpression(newExpression, bindings, environment)
   }
 
   /*
     After reducing each level of expression(Lisp AST), we have a value list to evaluate
  */
-  let reduceValueList = (valueList: list<expressionValue>): result<expressionValue, 'e> =>
+  let reduceValueList = (valueList: list<expressionValue>, environment): result<expressionValue, 'e> =>
     switch valueList {
-    | list{EvCall(fName), ...args} => (fName, args->Belt.List.toArray)->BuiltIn.dispatch
+    | list{EvCall(fName), ...args} => (fName, args->Belt.List.toArray)->BuiltIn.dispatch(environment)
     // "(lambda(x=>internal) param)"
     | list{EvLambda((parameters, internal)), ...args} =>
-      applyParametersToLambda(internal, parameters, args)
+      applyParametersToLambda(internal, parameters, args, environment)
     | _ => valueList->Belt.List.toArray->ExpressionValue.EvArray->Ok
     }
 
-  let rec seekMacros = (expression: t, bindings: T.bindings): result<t, 'e> =>
+  let rec seekMacros = (expression: t, bindings: T.bindings, environment): result<t, 'e> =>
     switch expression {
     | T.EValue(_value) => expression->Ok
     | T.EBindings(_value) => expression->Ok
@@ -108,17 +112,17 @@ let rec reduceExpression = (expression: t, bindings: T.bindings): result<express
         ) =>
           racc->Result.flatMap(acc => {
             each
-            ->seekMacros(bindings)
+            ->seekMacros(bindings, environment)
             ->Result.flatMap(newNode => {
               acc->Belt.List.add(newNode)->Ok
             })
           })
         )
-        racc->Result.flatMap(acc => acc->doMacroCall(bindings))
+        racc->Result.flatMap(acc => acc->doMacroCall(bindings, environment))
       }
     }
 
-  let rec reduceExpandedExpression = (expression: t): result<expressionValue, 'e> =>
+  let rec reduceExpandedExpression = (expression: t, environment): result<expressionValue, 'e> =>
     switch expression {
     | T.EList(list{T.EValue(EvCall("$lambda")), T.EParameters(parameters), functionDefinition}) =>
       EvLambda((parameters, functionDefinition->castExpressionToInternalCode))->Ok
@@ -130,36 +134,36 @@ let rec reduceExpression = (expression: t, bindings: T.bindings): result<express
         ) =>
           racc->Result.flatMap(acc => {
             each
-            ->reduceExpandedExpression
+            ->reduceExpandedExpression(environment)
             ->Result.flatMap(newNode => {
               acc->Belt.List.add(newNode)->Ok
             })
           })
         )
-        racc->Result.flatMap(acc => acc->reduceValueList)
+        racc->Result.flatMap(acc => acc->reduceValueList(environment))
       }
     | EBindings(_bindings) => RETodo("Error: Bindings cannot be reduced to values")->Error
     | EParameters(_parameters) =>
       RETodo("Error: Lambda Parameters cannot be reduced to values")->Error
     }
 
-  let rExpandedExpression: result<t, 'e> = expression->seekMacros(bindings)
+  let rExpandedExpression: result<t, 'e> = expression->seekMacros(bindings, environment)
   rExpandedExpression->Result.flatMap(expandedExpression =>
-    expandedExpression->reduceExpandedExpression
+    expandedExpression->reduceExpandedExpression(environment)
   )
 }
 
-let evalUsingExternalBindingsExpression_ = (aExpression, bindings): result<expressionValue, 'e> =>
-  reduceExpression(aExpression, bindings)
+let evalUsingExternalBindingsExpression_ = (aExpression, bindings, environment): result<expressionValue, 'e> =>
+  reduceExpression(aExpression, bindings, environment)
 
 /*
   Evaluates MathJs code via Reducer using bindings and answers the result.
   When bindings are used, the code is a partial code as if it is cut from a larger code.
   Therefore all statements are assignments.
 */
-let evalPartialUsingExternalBindings_ = (codeText: string, bindings: T.bindings) => {
+let evalPartial_ = (codeText: string, bindings: T.bindings, environment: environment) => {
   parsePartial(codeText)->Result.flatMap(expression =>
-    expression->evalUsingExternalBindingsExpression_(bindings)
+    expression->evalUsingExternalBindingsExpression_(bindings, environment)
   )
 }
 
@@ -168,23 +172,12 @@ let evalPartialUsingExternalBindings_ = (codeText: string, bindings: T.bindings)
   When bindings are used, the code is a partial code as if it is cut from a larger code.
   Therefore all statments are assignments.
 */
-let evalOuterWBindings_ = (codeText: string, bindings: T.bindings) => {
+let evalOuter_ = (codeText: string, bindings: T.bindings, environment: environment) => {
   parseOuter(codeText)->Result.flatMap(expression =>
-    expression->evalUsingExternalBindingsExpression_(bindings)
+    expression->evalUsingExternalBindingsExpression_(bindings, environment)
   )
 }
 
-/*
-  Evaluates MathJs code and bindings via Reducer and answers the result
-*/
-let eval = (codeText: string) => {
-  parse(codeText)->Result.flatMap(expression =>
-    expression->evalUsingExternalBindingsExpression_(defaultBindings)
-  )
-}
-
-type externalBindings = ReducerInterface.ExpressionValue.externalBindings //Js.Dict.t<expressionValue>
-
 let externalBindingsToBindings = (externalBindings: externalBindings): T.bindings => {
   let keys = Js.Dict.keys(externalBindings)
   keys->Belt.Array.reduce(defaultBindings, (acc, key) => {
@@ -192,28 +185,41 @@ let externalBindingsToBindings = (externalBindings: externalBindings): T.binding
     acc->Belt.Map.String.set(key, T.EValue(value))
   })
 }
-/*
-  Evaluates code with external bindings. External bindings are a record of expression values.
-*/
-let evalUsingExternalBindings = (code: string, externalBindings: externalBindings) => {
-  let bindings = externalBindings->externalBindingsToBindings
-  evalOuterWBindings_(code, bindings)
+
+let evaluateUsingOptions = (
+  ~environment: option<ReducerInterface_ExpressionValue.environment>, 
+  ~externalBindings: option<ReducerInterface_ExpressionValue.externalBindings>, 
+  ~isPartial: option<bool>, 
+  code: string): result<expressionValue, errorValue> => {
+
+  let anEnvironment = switch environment {
+    | Some(env) => env
+    | None => ReducerInterface_ExpressionValue.defaultEnvironment
+  }
+
+  let anExternalBindings = switch externalBindings {
+    | Some(bindings) => bindings
+    | None => ReducerInterface_ExpressionValue.defaultExternalBindings
+  }
+
+  let anIsPartial = switch isPartial {
+    | Some(isPartial) => isPartial
+    | None => false
+  }
+
+  let bindings = anExternalBindings->externalBindingsToBindings
+
+  if anIsPartial {
+    evalPartial_(code, bindings, anEnvironment)
+  } else {
+    evalOuter_(code, bindings, anEnvironment)
+  }
 }
 
 /*
-  Evaluates code with external bindings. External bindings are a record of expression values.
-  The code is a partial code as if it is cut from a larger code. Therefore all statments are assignments.
+  Evaluates MathJs code and bindings via Reducer and answers the result
 */
-let evalPartialUsingExternalBindings = (code: string, externalBindings: externalBindings): result<
-  externalBindings,
-  'e,
-> => {
-  let bindings = externalBindings->externalBindingsToBindings
-  let answer = evalPartialUsingExternalBindings_(code, bindings)
-  answer->Result.flatMap(answer =>
-    switch answer {
-    | EvRecord(aRecord) => Ok(aRecord)
-    | _ => RETodo("TODO: External bindings must be returned")->Error
-    }
-  )
+let evaluate = (code: string): result<expressionValue, errorValue> => {
+  evaluateUsingOptions(~environment=None, ~externalBindings=None, ~isPartial=None, code)
 }
+let eval = evaluate

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

@@ -22,6 +22,9 @@ type rec expressionValue =
 
 @genType
 type externalBindings = Js.Dict.t<expressionValue>
+@genType
+let defaultExternalBindings: externalBindings = Js.Dict.empty()
+
 
 type functionCall = (string, array<expressionValue>)
 
@@ -84,3 +87,8 @@ let toStringResultRecord = x =>
   | Ok(a) => `Ok(${toStringRecord(a)})`
   | Error(m) => `Error(${ErrorValue.errorToString(m)})`
   }
+
+@genType
+type environment = {dummy: int}
+@genType
+let defaultEnvironment: environment = {dummy: 0}

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

@@ -14,8 +14,8 @@ type expressionValue = ExpressionValue.expressionValue
   Map external calls of Reducer
 */
 
-let dispatch = (call: ExpressionValue.functionCall, chain): result<expressionValue, 'e> =>
-  ReducerInterface_GenericDistribution.dispatch(call) |> E.O.default(chain(call))
+let dispatch = (call: ExpressionValue.functionCall, environment, chain): result<expressionValue, 'e> =>
+  ReducerInterface_GenericDistribution.dispatch(call, environment) |> E.O.default(chain(call, environment))
 /*
 If your dispatch is too big you can divide it into smaller dispatches and pass the call so that it gets called finally.
 

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

@@ -180,7 +180,7 @@ module Math = {
   let e = 2.718281828459
 }
 
-let dispatchToGenericOutput = (call: ExpressionValue.functionCall): option<
+let dispatchToGenericOutput = (call: ExpressionValue.functionCall, _environment): option<
   DistributionOperation.outputType,
 > => {
   let (fnName, args) = call
@@ -266,6 +266,6 @@ let genericOutputToReducerValue = (o: DistributionOperation.outputType): result<
   | GenDistError(err) => Error(REDistributionError(err))
   }
 
-let dispatch = call => {
-  dispatchToGenericOutput(call)->E.O2.fmap(genericOutputToReducerValue)
+let dispatch = (call, environment) => {
+  dispatchToGenericOutput(call, environment)->E.O2.fmap(genericOutputToReducerValue)
 }

packages/squiggle-lang/src/rescript/ReducerInterface/ReducerInterface_GenericDistribution.resi

@@ -1,3 +1,3 @@
-let dispatch: ReducerInterface_ExpressionValue.functionCall => option<
+let dispatch: (ReducerInterface_ExpressionValue.functionCall, ReducerInterface_ExpressionValue.environment) => option<
   result<ReducerInterface_ExpressionValue.expressionValue, Reducer_ErrorValue.errorValue>,
 >