foreign function interface

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

@@ -9,3 +9,8 @@ describe("map reduce", () => {
   testEvalToBe("arr=[1,2,3]; reverse(arr)", "Ok([3,2,1])")
   testEvalToBe("check(x)=(x==2);arr=[1,2,3]; keep(arr,check)", "Ok([2])")
 })
+
+Skip.describe("map reduce (sam)", () => {
+  testEvalToBe("addone(x)=x+1; map(2, addone)", "Error???")
+  testEvalToBe("addone(x)=x+1; map(2, {x: addone})", "Error???")
+})

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

@@ -1,11 +1,32 @@
 module ErrorValue = Reducer_ErrorValue
 module Expression = Reducer_Expression
+module ExpressionValue = ReducerInterface_ExpressionValue
+module Lambda = Reducer_Expression_Lambda
 
 type environment = ReducerInterface_ExpressionValue.environment
 type errorValue = Reducer_ErrorValue.errorValue
 type expressionValue = ReducerInterface_ExpressionValue.expressionValue
 type externalBindings = ReducerInterface_ExpressionValue.externalBindings
+type lambdaValue = ExpressionValue.lambdaValue
+
 let evaluate = Expression.evaluate
 let evaluateUsingOptions = Expression.evaluateUsingOptions
 let evaluatePartialUsingExternalBindings = Expression.evaluatePartialUsingExternalBindings
 let parse = Expression.parse
+
+let foreignFunctionInterface = (
+  lambdaValue: lambdaValue,
+  argArray: array<expressionValue>,
+  environment: ExpressionValue.environment,
+) => {
+  Lambda.foreignFunctionInterface(
+    lambdaValue,
+    argArray,
+    environment,
+    Expression.reduceExpression,
+  )
+}
+
+let defaultEnvironment = ExpressionValue.defaultEnvironment
+
+let defaultExternalBindings = ExpressionValue.defaultExternalBindings

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

@@ -9,6 +9,9 @@ type errorValue = Reducer_ErrorValue.errorValue
 type expressionValue = ReducerInterface_ExpressionValue.expressionValue
 @genType
 type externalBindings = ReducerInterface_ExpressionValue.externalBindings
+@genType
+type lambdaValue = ReducerInterface_ExpressionValue.lambdaValue
+
 
 @genType
 let evaluateUsingOptions: (
@@ -26,3 +29,16 @@ let evaluatePartialUsingExternalBindings: (
 let evaluate: string => result<expressionValue, errorValue>
 
 let parse: string => result<Expression.expression, errorValue>
+
+@genType
+let foreignFunctionInterface: (
+  QuriSquiggleLang.ReducerInterface_ExpressionValue.lambdaValue,
+  array<QuriSquiggleLang.ReducerInterface_ExpressionValue.expressionValue>,
+  QuriSquiggleLang.ReducerInterface_ExpressionValue.environment,
+) => result<expressionValue, errorValue>
+
+@genType
+let defaultEnvironment: environment
+
+@genType
+let defaultExternalBindings: externalBindings

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

@@ -57,3 +57,13 @@ let applyParametersToLambda = (
 
 let doLambdaCall = (lambdaValue: ExpressionValue.lambdaValue, args, environment, reducer) =>
   applyParametersToLambda(lambdaValue, args, environment, reducer)
+
+let foreignFunctionInterface = (
+  lambdaValue: ExpressionValue.lambdaValue,
+  argArray: array<expressionValue>,
+  environment: ExpressionValue.environment,
+  reducer: ExpressionT.reducerFn,
+): result<expressionValue, 'e> => {
+  let args = argArray->Belt.List.fromArray
+  applyParametersToLambda(lambdaValue, args, environment, reducer)
+}