Merge pull request #333 from quantified-uncertainty/reducer-dev

Bindings in and Out

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

@@ -7,5 +7,66 @@ open Expect
 let expectParseToBe = (expr: string, answer: string) =>
   Reducer.parse(expr)->Expression.toStringResult->expect->toBe(answer)
 
+let expectParseOuterToBe = (expr: string, answer: string) =>
+  Reducer.parseOuter(expr)->Expression.toStringResult->expect->toBe(answer)
+
+let expectParsePartialToBe = (expr: string, answer: string) =>
+  Reducer.parsePartial(expr)->Expression.toStringResult->expect->toBe(answer)
+
 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)->ExpressionValue.toStringResult->expect->toBe(answer)
+
+let expectEvalPartialBindingsToBe = (
+  expr: string,
+  bindings: Reducer.externalBindings,
+  answer: string,
+) =>
+  Reducer.evaluatePartialUsingExternalBindings(expr, bindings)
+  ->ExpressionValue.toStringResultRecord
+  ->expect
+  ->toBe(answer)
+
+let testParseToBe = (expr, answer) => test(expr, () => expectParseToBe(expr, answer))
+let testParseOuterToBe = (expr, answer) => test(expr, () => expectParseOuterToBe(expr, answer))
+let testParsePartialToBe = (expr, answer) => test(expr, () => expectParsePartialToBe(expr, answer))
+let testDescriptionParseToBe = (desc, expr, answer) =>
+  test(desc, () => expectParseToBe(expr, answer))
+
+let testEvalToBe = (expr, answer) => test(expr, () => expectEvalToBe(expr, answer))
+let testDescriptionEvalToBe = (desc, expr, answer) => test(desc, () => expectEvalToBe(expr, answer))
+let testEvalBindingsToBe = (expr, bindingsList, answer) =>
+  test(expr, () => expectEvalBindingsToBe(expr, bindingsList->Js.Dict.fromList, answer))
+let testEvalPartialBindingsToBe = (expr, bindingsList, answer) =>
+  test(expr, () => expectEvalPartialBindingsToBe(expr, bindingsList->Js.Dict.fromList, answer))
+
+module MySkip = {
+  let testParseToBe = (expr, answer) => Skip.test(expr, () => expectParseToBe(expr, answer))
+  let testParseOuterToBe = (expr, answer) =>
+    Skip.test(expr, () => expectParseOuterToBe(expr, answer))
+  let testParsePartialToBe = (expr, answer) =>
+    Skip.test(expr, () => expectParsePartialToBe(expr, answer))
+  let testEvalToBe = (expr, answer) => Skip.test(expr, () => expectEvalToBe(expr, answer))
+  let testEvalBindingsToBe = (expr, bindingsList, answer) =>
+    Skip.test(expr, () => expectEvalBindingsToBe(expr, bindingsList->Js.Dict.fromList, answer))
+  let testEvalPartialBindingsToBe = (expr, bindingsList, answer) =>
+    Skip.test(expr, () =>
+      expectEvalPartialBindingsToBe(expr, bindingsList->Js.Dict.fromList, answer)
+    )
+}
+module MyOnly = {
+  let testParseToBe = (expr, answer) => Only.test(expr, () => expectParseToBe(expr, answer))
+  let testParseOuterToBe = (expr, answer) =>
+    Only.test(expr, () => expectParseOuterToBe(expr, answer))
+  let testParsePartialToBe = (expr, answer) =>
+    Only.test(expr, () => expectParsePartialToBe(expr, answer))
+  let testEvalToBe = (expr, answer) => Only.test(expr, () => expectEvalToBe(expr, answer))
+  let testEvalBindingsToBe = (expr, bindingsList, answer) =>
+    Only.test(expr, () => expectEvalBindingsToBe(expr, bindingsList->Js.Dict.fromList, answer))
+  let testEvalPartialBindingsToBe = (expr, bindingsList, answer) =>
+    Only.test(expr, () =>
+      expectEvalPartialBindingsToBe(expr, bindingsList->Js.Dict.fromList, answer)
+    )
+}

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

@@ -0,0 +1,60 @@
+open Jest
+open Reducer_TestHelpers
+
+describe("Parse for Bindings", () => {
+  testParseOuterToBe("x", "Ok((:$$bindExpression (:$$bindings) :x))")
+  testParseOuterToBe("x+1", "Ok((:$$bindExpression (:$$bindings) (:add :x 1)))")
+  testParseOuterToBe(
+    "y = x+1; y",
+    "Ok((:$$bindExpression (:$$bindStatement (:$$bindings) (:$let :y (:add :x 1))) :y))",
+  )
+})
+
+describe("Parse Partial", () => {
+  testParsePartialToBe(
+    "x",
+    "Ok((:$$bindExpression (:$$bindStatement (:$$bindings) :x) (:$exportVariablesExpression)))",
+  )
+  testParsePartialToBe(
+    "y=x",
+    "Ok((:$$bindExpression (:$$bindStatement (:$$bindings) (:$let :y :x)) (:$exportVariablesExpression)))",
+  )
+  testParsePartialToBe(
+    "y=x+1",
+    "Ok((:$$bindExpression (:$$bindStatement (:$$bindings) (:$let :y (:add :x 1))) (:$exportVariablesExpression)))",
+  )
+  testParsePartialToBe(
+    "y = x+1; z = y",
+    "Ok((:$$bindExpression (:$$bindStatement (:$$bindStatement (:$$bindings) (:$let :y (:add :x 1))) (:$let :z :y)) (:$exportVariablesExpression)))",
+  )
+})
+
+describe("Eval with Bindings", () => {
+  testEvalBindingsToBe("x", list{("x", ExpressionValue.EvNumber(1.))}, "Ok(1)")
+  testEvalBindingsToBe("x+1", list{("x", ExpressionValue.EvNumber(1.))}, "Ok(2)")
+  testEvalBindingsToBe("y = x+1; y", list{("x", ExpressionValue.EvNumber(1.))}, "Ok(2)")
+})
+
+/*
+    Partial code is a partial code fragment that is cut out from a larger code.
+    Therefore it does not end with an expression.
+*/
+describe("Eval Partial", () => {
+  testEvalPartialBindingsToBe(
+    //   A partial cannot end with an expression
+    "x",
+    list{("x", ExpressionValue.EvNumber(1.))},
+    "Error(Assignment expected)",
+  )
+  testEvalPartialBindingsToBe("y=x", list{("x", ExpressionValue.EvNumber(1.))}, "Ok({x: 1, y: 1})")
+  testEvalPartialBindingsToBe(
+    "y=x+1",
+    list{("x", ExpressionValue.EvNumber(1.))},
+    "Ok({x: 1, y: 2})",
+  )
+  testEvalPartialBindingsToBe(
+    "y = x+1; z = y",
+    list{("x", ExpressionValue.EvNumber(1.))},
+    "Ok({x: 1, y: 2, z: 2})",
+  )
+})

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

@@ -0,0 +1,12 @@
+open Jest
+open Reducer_TestHelpers
+
+Skip.describe("Parse ternary operator", () => {
+  testParseToBe("true ? 'YES' : 'NO'", "Ok('YES')")
+  testParseToBe("false ? 'YES' : 'NO'", "Ok('NO')")
+})
+
+Skip.describe("Evaluate ternary operator", () => {
+  testEvalToBe("true ? 'YES' : 'NO'", "Ok('YES')")
+  testEvalToBe("false ? 'YES' : 'NO'", "Ok('NO')")
+})

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

@@ -1,15 +1,6 @@
 open Jest
 open Reducer_TestHelpers
 
-let testParseToBe = (expr, answer) => test(expr, () => expectParseToBe(expr, answer))
-
-let testDescriptionParseToBe = (desc, expr, answer) =>
-  test(desc, () => expectParseToBe(expr, answer))
-
-let testEvalToBe = (expr, answer) => test(expr, () => expectEvalToBe(expr, answer))
-
-let testDescriptionEvalToBe = (desc, expr, answer) => test(desc, () => expectEvalToBe(expr, answer))
-
 describe("reducer using mathjs parse", () => {
   // Test the MathJs parser compatibility
   // Those tests toString that there is a semantic mapping from MathJs to Expression

packages/squiggle-lang/package.json

@@ -13,7 +13,7 @@
     "test:rescript": "jest --modulePathIgnorePatterns=__tests__/TS/*",
     "test:watch": "jest --watchAll",
     "coverage:rescript": "rm -f *.coverage; yarn clean; BISECT_ENABLE=yes yarn build; yarn test:rescript; bisect-ppx-report html",
-    "coverage:ts": "nyc --reporter=lcov yarn test:ts",
+    "coverage:ts": "yarn clean; yarn build; nyc --reporter=lcov yarn test:ts",
     "coverage:rescript:ci": "yarn clean; BISECT_ENABLE=yes yarn build; yarn test:rescript; bisect-ppx-report send-to Codecov",
     "coverage:ts:ci": "yarn coverage:ts && codecov",
     "lint:rescript": "./lint.sh",
@@ -48,6 +48,7 @@
     "gentype": "^4.3.0",
     "jest": "^27.5.1",
     "moduleserve": "0.9.1",
+    "reanalyze": "^2.19.0",
     "nyc": "^15.1.0",
     "ts-jest": "^27.1.4",
     "ts-loader": "^9.2.8",

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

@@ -6,5 +6,10 @@ module Js = Reducer_Js
 module MathJs = Reducer_MathJs
 
 type expressionValue = Reducer_Expression.expressionValue
+type externalBindings = Expression.externalBindings
 let evaluate = Expression.eval
+let evaluateUsingExternalBindings = Expression.evalUsingExternalBindings
+let evaluatePartialUsingExternalBindings = Expression.evalPartialUsingExternalBindings
 let parse = Expression.parse
+let parseOuter = Expression.parseOuter
+let parsePartial = Expression.parsePartial

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

@@ -7,7 +7,20 @@ module MathJs = Reducer_MathJs
 
 @genType
 type expressionValue = ReducerInterface_ExpressionValue.expressionValue
-
+@genType
+type externalBindings = ReducerInterface_ExpressionValue.externalBindings
 @genType
 let evaluate: string => result<expressionValue, Reducer_ErrorValue.errorValue>
+@genType
+let evaluateUsingExternalBindings: (
+  string,
+  externalBindings,
+) => result<expressionValue, Reducer_ErrorValue.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>

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

@@ -1 +1,2 @@
 module Builtin = Reducer_Dispatch_BuiltIn
+module BuiltinMacros = Reducer_Dispatch_BuiltInMacros

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

@@ -0,0 +1,122 @@
+/*
+  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.
+*/
+module ExpressionT = Reducer_Expression_T
+module ExpressionValue = ReducerInterface.ExpressionValue
+module Result = Belt.Result
+
+open Reducer_ErrorValue
+
+type expression = ExpressionT.expression
+
+type reducerFn = (
+  expression,
+  ExpressionT.bindings,
+) => result<ExpressionValue.expressionValue, errorValue>
+
+let dispatchMacroCall = (
+  list: list<expression>,
+  bindings: ExpressionT.bindings,
+  reduceExpression: reducerFn,
+): result<expression, 'e> => {
+  let rec replaceSymbols = (expression: expression, bindings: ExpressionT.bindings): result<
+    expression,
+    errorValue,
+  > =>
+    switch expression {
+    | ExpressionT.EValue(EvSymbol(aSymbol)) =>
+      switch bindings->Belt.Map.String.get(aSymbol) {
+      | Some(boundExpression) => boundExpression->Ok
+      | None => RESymbolNotFound(aSymbol)->Error
+      }
+    | ExpressionT.EValue(_) => expression->Ok
+    | ExpressionT.EBindings(_) => expression->Ok
+    | ExpressionT.EList(list) => {
+        let racc = list->Belt.List.reduceReverse(Ok(list{}), (racc, each: expression) =>
+          racc->Result.flatMap(acc => {
+            each
+            ->replaceSymbols(bindings)
+            ->Result.flatMap(newNode => {
+              acc->Belt.List.add(newNode)->Ok
+            })
+          })
+        )
+        racc->Result.map(acc => acc->ExpressionT.EList)
+      }
+    }
+
+  let doBindStatement = (statement: expression, bindings: ExpressionT.bindings) => {
+    switch statement {
+    | ExpressionT.EList(list{
+        ExpressionT.EValue(EvCall("$let")),
+        ExpressionT.EValue(EvSymbol(aSymbol)),
+        expressionToReduce,
+      }) => {
+        let rNewExpressionToReduce = replaceSymbols(expressionToReduce, bindings)
+
+        let rNewValue =
+          rNewExpressionToReduce->Result.flatMap(newExpressionToReduce =>
+            reduceExpression(newExpressionToReduce, bindings)
+          )
+
+        let rNewExpression = rNewValue->Result.map(newValue => ExpressionT.EValue(newValue))
+        rNewExpression->Result.map(newExpression =>
+          Belt.Map.String.set(bindings, aSymbol, newExpression)->ExpressionT.EBindings
+        )
+      }
+    | _ => REAssignmentExpected->Error
+    }
+  }
+
+  let doExportVariableExpression = (bindings: ExpressionT.bindings) => {
+    let emptyDictionary: Js.Dict.t<ExpressionValue.expressionValue> = Js.Dict.empty()
+    let reducedBindings = bindings->Belt.Map.String.keep((_key, value) =>
+      switch value {
+      | ExpressionT.EValue(_) => true
+      | _ => false
+      }
+    )
+    let externalBindings = reducedBindings->Belt.Map.String.reduce(emptyDictionary, (
+      acc,
+      key,
+      expressionValue,
+    ) => {
+      let value = switch expressionValue {
+      | EValue(aValue) => aValue
+      | _ => EvSymbol("internal")
+      }
+      Js.Dict.set(acc, key, value)
+      acc
+    })
+    externalBindings->EvRecord->ExpressionT.EValue->Ok
+  }
+
+  let doBindExpression = (expression: expression, bindings: ExpressionT.bindings) =>
+    switch expression {
+    | ExpressionT.EList(list{ExpressionT.EValue(EvCall("$let")), ..._}) =>
+      REExpressionExpected->Error
+    | ExpressionT.EList(list{ExpressionT.EValue(EvCall("$exportVariablesExpression"))}) =>
+      doExportVariableExpression(bindings)
+    | _ => replaceSymbols(expression, bindings)
+    }
+
+  switch list {
+  | list{ExpressionT.EValue(EvCall("$$bindings"))} => bindings->ExpressionT.EBindings->Ok
+
+  | list{
+      ExpressionT.EValue(EvCall("$$bindStatement")),
+      ExpressionT.EBindings(bindings),
+      statement,
+    } =>
+    doBindStatement(statement, bindings)
+  | list{
+      ExpressionT.EValue(EvCall("$$bindExpression")),
+      ExpressionT.EBindings(bindings),
+      expression,
+    } =>
+    doBindExpression(expression, bindings)
+  | _ => list->ExpressionT.EList->Ok
+  }
+}

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

@@ -39,12 +39,26 @@ let parse_ = (expr: string, parser, converter): result<t, errorValue> =>
 let parse = (mathJsCode: string): result<t, errorValue> =>
   mathJsCode->parse_(MathJs.Parse.parse, MathJs.ToExpression.fromNode)
 
+let parsePartial = (mathJsCode: string): result<t, errorValue> =>
+  mathJsCode->parse_(MathJs.Parse.parse, MathJs.ToExpression.fromPartialNode)
+
+let parseOuter = (mathJsCode: string): result<t, errorValue> =>
+  mathJsCode->parse_(MathJs.Parse.parse, MathJs.ToExpression.fromOuterNode)
+
 let defaultBindings: T.bindings = Belt.Map.String.empty
 
 /*
   Recursively evaluate/reduce the expression (Lisp AST)
 */
-let reduceExpression = (expression: t, bindings: T.bindings): result<expressionValue, 'e> => {
+let rec reduceExpression = (expression: t, bindings: T.bindings): 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)
+
   /*
     After reducing each level of expression(Lisp AST), we have a value list to evaluate
  */
@@ -54,72 +68,10 @@ let reduceExpression = (expression: t, bindings: T.bindings): result<expressionV
     | _ => valueList->Belt.List.toArray->ExpressionValue.EvArray->Ok
     }
 
-  /*
-    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> => {
-    let dispatchMacroCall = (list: list<t>, bindings: T.bindings): result<t, 'e> => {
-      let rec replaceSymbols = (expression: t, bindings: T.bindings): result<t, errorValue> =>
-        switch expression {
-        | T.EValue(EvSymbol(aSymbol)) =>
-          switch bindings->Belt.Map.String.get(aSymbol) {
-          | Some(boundExpression) => boundExpression->Ok
-          | None => RESymbolNotFound(aSymbol)->Error
-          }
-        | T.EValue(_) => expression->Ok
-        | T.EBindings(_) => expression->Ok
-        | T.EList(list) => {
-            let racc = list->Belt.List.reduceReverse(Ok(list{}), (racc, each: expression) =>
-              racc->Result.flatMap(acc => {
-                each
-                ->replaceSymbols(bindings)
-                ->Result.flatMap(newNode => {
-                  acc->Belt.List.add(newNode)->Ok
-                })
-              })
-            )
-            racc->Result.map(acc => acc->T.EList)
-          }
-        }
-
-      let doBindStatement = (statement: t, bindings: T.bindings) => {
-        switch statement {
-        | T.EList(list{T.EValue(EvCall("$let")), T.EValue(EvSymbol(aSymbol)), expression}) => {
-            let rNewExpression = replaceSymbols(expression, bindings)
-            rNewExpression->Result.map(newExpression =>
-              Belt.Map.String.set(bindings, aSymbol, newExpression)->T.EBindings
-            )
-          }
-        | _ => REAssignmentExpected->Error
-        }
-      }
-
-      let doBindExpression = (expression: t, bindings: T.bindings) => {
-        switch expression {
-        | T.EList(list{T.EValue(EvCall("$let")), ..._}) => REExpressionExpected->Error
-        | _ => replaceSymbols(expression, bindings)
-        }
-      }
-
-      switch list {
-      | list{T.EValue(EvCall("$$bindings"))} => bindings->T.EBindings->Ok
-
-      | list{T.EValue(EvCall("$$bindStatement")), T.EBindings(bindings), statement} =>
-        doBindStatement(statement, bindings)
-      | list{T.EValue(EvCall("$$bindExpression")), T.EBindings(bindings), expression} =>
-        doBindExpression(expression, bindings)
-      | _ => list->T.EList->Ok
-      }
-    }
-
-    list->dispatchMacroCall(bindings)
-  }
-
   let rec seekMacros = (expression: t, bindings: T.bindings): result<t, 'e> =>
     switch expression {
-    | T.EValue(_) => expression->Ok
+    | T.EValue(_value) => expression->Ok
+    | T.EBindings(_value) => expression->Ok
     | T.EList(list) => {
         let racc: result<list<t>, 'e> = list->Belt.List.reduceReverse(Ok(list{}), (
           racc,
@@ -135,7 +87,6 @@ let reduceExpression = (expression: t, bindings: T.bindings): result<expressionV
         )
         racc->Result.flatMap(acc => acc->doMacroCall(bindings))
       }
-    | T.EBindings(bindings) => T.EBindings(bindings)->Ok
     }
 
   let rec reduceExpandedExpression = (expression: t): result<expressionValue, 'e> =>
@@ -156,7 +107,7 @@ let reduceExpression = (expression: t, bindings: T.bindings): result<expressionV
         )
         racc->Result.flatMap(acc => acc->reduceValueList)
       }
-    | T.EBindings(_) => RETodo("Cannot return bindings")->Error
+    | EBindings(_bindings) => RETodo("Error: Bindings cannot be reduced to values")->Error
     }
 
   let rExpandedExpression: result<t, 'e> = expression->seekMacros(bindings)
@@ -165,17 +116,69 @@ let reduceExpression = (expression: t, bindings: T.bindings): result<expressionV
   )
 }
 
-let evalWBindingsExpression = (aExpression, bindings): result<expressionValue, 'e> =>
+let evalUsingExternalBindingsExpression_ = (aExpression, bindings): result<expressionValue, 'e> =>
   reduceExpression(aExpression, bindings)
 
 /*
-  Evaluates MathJs code via Reducer using bindings and answers the result
+  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 evalWBindings = (codeText: string, bindings: T.bindings) => {
-  parse(codeText)->Result.flatMap(code => code->evalWBindingsExpression(bindings))
+let evalPartialUsingExternalBindings_ = (codeText: string, bindings: T.bindings) => {
+  parsePartial(codeText)->Result.flatMap(expression =>
+    expression->evalUsingExternalBindingsExpression_(bindings)
+  )
 }
 
 /*
-  Evaluates MathJs code via Reducer and answers the result
+  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 statments are assignments.
 */
-let eval = (code: string) => evalWBindings(code, defaultBindings)
+let evalOuterWBindings_ = (codeText: string, bindings: T.bindings) => {
+  parseOuter(codeText)->Result.flatMap(expression => expression->evalUsingExternalBindingsExpression_(bindings))
+}
+
+/*
+  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) => {
+    let value = Js.Dict.unsafeGet(externalBindings, key)
+    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)
+}
+
+/*
+  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.
+*/
+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
+    }
+  )
+}

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

@@ -9,6 +9,22 @@ type expression = ExpressionT.expression
 type expressionValue = ExpressionValue.expressionValue
 type errorValue = ErrorValue.errorValue
 
+let passToFunction = (fName: string, rLispArgs): result<expression, errorValue> => {
+  let toEvCallValue = (name: string): expression => name->ExpressionValue.EvCall->ExpressionT.EValue
+
+  let fn = fName->toEvCallValue
+  rLispArgs->Result.flatMap(lispArgs => list{fn, ...lispArgs}->ExpressionT.EList->Ok)
+}
+
+type blockTag =
+  | ImportVariablesStatement
+  | ExportVariablesExpression
+type tagOrNode =
+  | BlockTag(blockTag)
+  | BlockNode(Parse.node)
+
+let toTagOrNode = block => BlockNode(block["node"])
+
 let rec fromNode = (mathJsNode: Parse.node): result<expression, errorValue> =>
   Parse.castNodeType(mathJsNode)->Result.flatMap(typedMathJsNode => {
     let fromNodeList = (nodeList: list<Parse.node>): result<list<expression>, 'e> =>
@@ -18,16 +34,9 @@ let rec fromNode = (mathJsNode: Parse.node): result<expression, errorValue> =>
         )
       )
 
-    let toEvCallValue = (name: string): expression =>
-      name->ExpressionValue.EvCall->ExpressionT.EValue
     let toEvSymbolValue = (name: string): expression =>
       name->ExpressionValue.EvSymbol->ExpressionT.EValue
 
-    let passToFunction = (fName: string, rLispArgs): result<expression, errorValue> => {
-      let fn = fName->toEvCallValue
-      rLispArgs->Result.flatMap(lispArgs => list{fn, ...lispArgs}->ExpressionT.EList->Ok)
-    }
-
     let caseFunctionNode = fNode => {
       let lispArgs = fNode["args"]->Belt.List.fromArray->fromNodeList
       passToFunction(fNode->Parse.nameOfFunctionNode, lispArgs)
@@ -94,27 +103,6 @@ let rec fromNode = (mathJsNode: Parse.node): result<expression, errorValue> =>
       aNode["items"]->Belt.List.fromArray->fromNodeList->Result.map(list => ExpressionT.EList(list))
     }
 
-    let caseBlockNode = (bNode): result<expression, errorValue> => {
-      let blocks = bNode["blocks"]
-      let initialBindings = passToFunction("$$bindings", list{}->Ok)
-      let lastIndex = Belt.Array.length(blocks) - 1
-      blocks->Belt.Array.reduceWithIndex(initialBindings, (rPreviousBindings, block, i) => {
-        rPreviousBindings->Result.flatMap(previousBindings => {
-          let node = block["node"]
-          let rStatement: result<expression, errorValue> = node->fromNode
-          let bindName = if i == lastIndex {
-            "$$bindExpression"
-          } else {
-            "$$bindStatement"
-          }
-          rStatement->Result.flatMap((statement: expression) => {
-            let lispArgs = list{previousBindings, statement}->Ok
-            passToFunction(bindName, lispArgs)
-          })
-        })
-      })
-    }
-
     let rFinalExpression: result<expression, errorValue> = switch typedMathJsNode {
     | MjAccessorNode(aNode) => caseAccessorNode(aNode["object"], aNode["index"])
     | MjArrayNode(aNode) => caseArrayNode(aNode)
@@ -124,8 +112,7 @@ let rec fromNode = (mathJsNode: Parse.node): result<expression, errorValue> =>
         let rExpr: result<expression, errorValue> = expr->Ok
         rExpr
       }
-    | MjBlockNode(bNode) => caseBlockNode(bNode)
-    // | MjBlockNode(bNode) => "statement"->toEvSymbolValue->Ok
+    | MjBlockNode(bNode) => bNode["blocks"]->Belt.Array.map(toTagOrNode)->caseTagOrNodes
     | MjConstantNode(cNode) =>
       cNode["value"]->JavaScript.Gate.jsToEv->Result.flatMap(v => v->ExpressionT.EValue->Ok)
     | MjFunctionNode(fNode) => fNode->caseFunctionNode
@@ -136,3 +123,73 @@ let rec fromNode = (mathJsNode: Parse.node): result<expression, errorValue> =>
     }
     rFinalExpression
   })
+and caseTagOrNodes = (tagOrNodes): result<expression, errorValue> => {
+  let initialBindings = passToFunction("$$bindings", list{}->Ok)
+  let lastIndex = Belt.Array.length(tagOrNodes) - 1
+  tagOrNodes->Belt.Array.reduceWithIndex(initialBindings, (rPreviousBindings, tagOrNode, i) => {
+    rPreviousBindings->Result.flatMap(previousBindings => {
+      let rStatement: result<expression, errorValue> = switch tagOrNode {
+      | BlockNode(node) => fromNode(node)
+      | BlockTag(tag) =>
+        switch tag {
+        | ImportVariablesStatement => passToFunction("$importVariablesStatement", list{}->Ok)
+        | ExportVariablesExpression => passToFunction("$exportVariablesExpression", list{}->Ok)
+        }
+      }
+
+      let bindName = if i == lastIndex {
+        "$$bindExpression"
+      } else {
+        "$$bindStatement"
+      }
+
+      rStatement->Result.flatMap((statement: expression) => {
+        let lispArgs = list{previousBindings, statement}->Ok
+        passToFunction(bindName, lispArgs)
+      })
+    })
+  })
+}
+
+let fromPartialNode = (mathJsNode: Parse.node): result<expression, errorValue> => {
+  Parse.castNodeType(mathJsNode)->Result.flatMap(typedMathJsNode => {
+    let casePartialBlockNode = (bNode: Parse.blockNode) => {
+      let blocksOrTags = bNode["blocks"]->Belt.Array.map(toTagOrNode)
+      let completed = Js.Array2.concat(blocksOrTags, [BlockTag(ExportVariablesExpression)])
+      completed->caseTagOrNodes
+    }
+
+    let casePartialExpression = (node: Parse.node) => {
+      let completed = [BlockNode(node), BlockTag(ExportVariablesExpression)]
+
+      completed->caseTagOrNodes
+    }
+
+    let rFinalExpression: result<expression, errorValue> = switch typedMathJsNode {
+    | MjBlockNode(bNode) => casePartialBlockNode(bNode)
+    | _ => casePartialExpression(mathJsNode)
+    }
+    rFinalExpression
+  })
+}
+
+let fromOuterNode = (mathJsNode: Parse.node): result<expression, errorValue> => {
+  Parse.castNodeType(mathJsNode)->Result.flatMap(typedMathJsNode => {
+    let casePartialBlockNode = (bNode: Parse.blockNode) => {
+      let blocksOrTags = bNode["blocks"]->Belt.Array.map(toTagOrNode)
+      let completed = blocksOrTags
+      completed->caseTagOrNodes
+    }
+
+    let casePartialExpression = (node: Parse.node) => {
+      let completed = [BlockNode(node)]
+      completed->caseTagOrNodes
+    }
+
+    let rFinalExpression: result<expression, errorValue> = switch typedMathJsNode {
+    | MjBlockNode(bNode) => casePartialBlockNode(bNode)
+    | _ => casePartialExpression(mathJsNode)
+    }
+    rFinalExpression
+  })
+}

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

@@ -16,6 +16,9 @@ type rec expressionValue =
   | EvString(string)
   | EvSymbol(string)
 
+@genType
+type externalBindings = Js.Dict.t<expressionValue>
+
 type functionCall = (string, array<expressionValue>)
 
 let rec toString = aValue =>
@@ -33,17 +36,18 @@ let rec toString = aValue =>
         ->Js.String.concatMany("")
       `[${args}]`
     }
-  | EvRecord(aRecord) => {
-      let pairs =
-        aRecord
-        ->Js.Dict.entries
-        ->Belt.Array.map(((eachKey, eachValue)) => `${eachKey}: ${toString(eachValue)}`)
-        ->Extra_Array.interperse(", ")
-        ->Js.String.concatMany("")
-      `{${pairs}}`
-    }
+  | EvRecord(aRecord) => aRecord->toStringRecord
   | EvDistribution(dist) => GenericDist.toString(dist)
   }
+and toStringRecord = aRecord => {
+  let pairs =
+    aRecord
+    ->Js.Dict.entries
+    ->Belt.Array.map(((eachKey, eachValue)) => `${eachKey}: ${toString(eachValue)}`)
+    ->Extra_Array.interperse(", ")
+    ->Js.String.concatMany("")
+  `{${pairs}}`
+}
 
 let toStringWithType = aValue =>
   switch aValue {
@@ -68,3 +72,9 @@ let toStringResult = x =>
   | Ok(a) => `Ok(${toString(a)})`
   | Error(m) => `Error(${ErrorValue.errorToString(m)})`
   }
+
+let toStringResultRecord = x =>
+  switch x {
+  | Ok(a) => `Ok(${toStringRecord(a)})`
+  | Error(m) => `Error(${ErrorValue.errorToString(m)})`
+  }

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

@@ -2,13 +2,13 @@ module ExpressionValue = ReducerInterface_ExpressionValue
 
 type expressionValue = ExpressionValue.expressionValue
 
-module Sample = {
-  // In real life real libraries should be somewhere else
-  /*
-    For an example of mapping polymorphic custom functions. To be deleted after real integration
- */
-  let customAdd = (a: float, b: float): float => {a +. b}
-}
+// module Sample = {
+//   // In real life real libraries should be somewhere else
+//   /*
+//     For an example of mapping polymorphic custom functions. To be deleted after real integration
+//  */
+//   let customAdd = (a: float, b: float): float => {a +. b}
+// }
 
 /*
   Map external calls of Reducer

yarn.lock

@@ -14639,6 +14639,11 @@ reading-time@^1.5.0:
   resolved "https://registry.yarnpkg.com/reading-time/-/reading-time-1.5.0.tgz#d2a7f1b6057cb2e169beaf87113cc3411b5bc5bb"
   integrity sha512-onYyVhBNr4CmAxFsKS7bz+uTLRakypIe4R+5A824vBSkQy/hB3fZepoVEf8OVAxzLvK+H/jm9TzpI3ETSm64Kg==
 
+reanalyze@^2.19.0:
+  version "2.19.0"
+  resolved "https://registry.yarnpkg.com/reanalyze/-/reanalyze-2.19.0.tgz#b34b16bd7249a07dc931bb3cc58410247bb36a03"
+  integrity sha512-ycVr19BH6b2J70BmG6nUIzrFWiBNLUCmip6D2NEPLpnJimF6wagE+BIksI6vcTCovqWjgNMKhFCbZKwm+5/8VQ==
+
 rechoir@^0.6.2:
   version "0.6.2"
   resolved "https://registry.yarnpkg.com/rechoir/-/rechoir-0.6.2.tgz#85204b54dba82d5742e28c96756ef43af50e3384"