parse assignment

packages/squiggle-lang/__tests__/Reducer/Reducer_MathJs/Reducer_MathJsParse_test.res

@@ -7,17 +7,13 @@ open Expect
 let expectParseToBe = (expr, answer) =>
   Parse.parse(expr)->Result.flatMap(Parse.castNodeType)->Parse.toStringResult->expect->toBe(answer)
 
-let testParse = (expr, answer) =>
-  test(expr, () => expectParseToBe(expr, answer))
+let testParse = (expr, answer) => test(expr, () => expectParseToBe(expr, answer))
 
-let testDescParse = (desc, expr, answer) =>
-  test(desc, () => expectParseToBe(expr, answer))
+let testDescParse = (desc, expr, answer) => test(desc, () => expectParseToBe(expr, answer))
 
-let skipTestParse = (expr, answer) =>
-    Skip.test(expr, () => expectParseToBe(expr, answer))
+let skipTestParse = (expr, answer) => Skip.test(expr, () => expectParseToBe(expr, answer))
 
-let skipDescTestParse = (desc, expr, answer) =>
-    Skip.test(desc, () => expectParseToBe(expr, answer))
+let skipDescTestParse = (desc, expr, answer) => Skip.test(desc, () => expectParseToBe(expr, answer))
 
 describe("MathJs parse", () => {
   describe("literals operators paranthesis", () => {
@@ -31,7 +27,7 @@ describe("MathJs parse", () => {
   })
 
   describe("variables", () => {
-    skipTestParse("x = 1", "???")
+    testParse("x = 1", "x = 1")
     skipTestParse("x", "???")
   })
 

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

@@ -3,6 +3,7 @@ type errorValue =
   | REFunctionExpected(string)
   | REJavaScriptExn(option<string>, option<string>) // Javascript Exception
   | RERecordPropertyNotFound(string, string)
+  | RESyntaxError(string)
   | RETodo(string) // To do
 
 type t = errorValue
@@ -24,5 +25,6 @@ let errorToString = err =>
       answer
     }
   | RERecordPropertyNotFound(msg, index) => `${msg}: ${index}`
+  | RESyntaxError(desc) => `Syntax Error: ${desc}`
   | RETodo(msg) => `TODO: ${msg}`
   }

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

@@ -7,7 +7,6 @@ open Reducer_ErrorValue
 
 type node = {"type": string, "isNode": bool, "comment": string}
 type arrayNode = {...node, "items": array<node>}
-//assignmentNode
 //blockNode
 //conditionalNode
 type constantNode = {...node, "value": unit}
@@ -23,9 +22,15 @@ type parenthesisNode = {...node, "content": node}
 //rangeNode
 //relationalNode
 type symbolNode = {...node, "name": string}
+type assignmentNode = {...node, "object": symbolNode, "value": node}
+type assignmentNodeWAccessor = {...node, "object": accessorNode, "value": node}
+type assignmentNodeWIndex = {...assignmentNodeWAccessor, "index": Js.null<indexNode>}
 
 external castAccessorNode: node => accessorNode = "%identity"
 external castArrayNode: node => arrayNode = "%identity"
+external castAssignmentNode: node => assignmentNode = "%identity"
+external castAssignmentNodeWAccessor: node => assignmentNodeWAccessor = "%identity"
+external castAssignmentNodeWIndex: node => assignmentNodeWIndex = "%identity"
 external castConstantNode: node => constantNode = "%identity"
 external castFunctionNode: node => functionNode = "%identity"
 external castIndexNode: node => indexNode = "%identity"
@@ -50,6 +55,7 @@ let parse = (expr: string): result<node, errorValue> =>
 type mathJsNode =
   | MjAccessorNode(accessorNode)
   | MjArrayNode(arrayNode)
+  | MjAssignmentNode(assignmentNode)
   | MjConstantNode(constantNode)
   | MjFunctionNode(functionNode)
   | MjIndexNode(indexNode)
@@ -58,10 +64,20 @@ type mathJsNode =
   | MjParenthesisNode(parenthesisNode)
   | MjSymbolNode(symbolNode)
 
-let castNodeType = (node: node) =>
+let castNodeType = (node: node) => {
+  let decideAssignmentNode = node => {
+    let iNode = node->castAssignmentNodeWIndex
+    if Js.Null.test(iNode["index"]) && iNode["object"]["type"] == "SymbolNode" {
+      node->castAssignmentNode->MjAssignmentNode->Ok
+    } else {
+      RESyntaxError("Assignment to index or property not supported")->Error
+    }
+  }
+
   switch node["type"] {
   | "AccessorNode" => node->castAccessorNode->MjAccessorNode->Ok
   | "ArrayNode" => node->castArrayNode->MjArrayNode->Ok
+  | "AssignmentNode" => node->decideAssignmentNode
   | "ConstantNode" => node->castConstantNode->MjConstantNode->Ok
   | "FunctionNode" => node->castFunctionNode->MjFunctionNode->Ok
   | "IndexNode" => node->castIndexNode->MjIndexNode->Ok
@@ -71,6 +87,7 @@ let castNodeType = (node: node) =>
   | "SymbolNode" => node->castSymbolNode->MjSymbolNode->Ok
   | _ => RETodo(`Argg, unhandled MathJsNode: ${node["type"]}`)->Error
   }
+}
 
 let rec toString = (mathJsNode: mathJsNode): string => {
   let toStringValue = (a: 'a): string =>
@@ -89,7 +106,8 @@ let rec toString = (mathJsNode: mathJsNode): string => {
   let toStringFunctionNode = (fnode: functionNode): string =>
     `${fnode["fn"]}(${fnode["args"]->toStringNodeArray})`
 
-  let toStringObjectEntry = ((key: string, value: node)): string => `${key}: ${value->toStringMathJsNode}`
+  let toStringObjectEntry = ((key: string, value: node)): string =>
+    `${key}: ${value->toStringMathJsNode}`
 
   let toStringObjectNode = (oNode: objectNode): string =>
     `{${oNode["properties"]
@@ -103,16 +121,21 @@ let rec toString = (mathJsNode: mathJsNode): string => {
     ->Belt.Array.map(each => toStringResult(each->castNodeType))
     ->Js.String.concatMany("")
 
+  let toStringSymbolNode = (sNode: symbolNode): string => sNode["name"]
+
   switch mathJsNode {
-  | MjAccessorNode(aNode) => `${aNode["object"]->toStringMathJsNode}[${aNode["index"]->toStringIndexNode}]`
+  | MjAccessorNode(aNode) =>
+    `${aNode["object"]->toStringMathJsNode}[${aNode["index"]->toStringIndexNode}]`
   | MjArrayNode(aNode) => `[${aNode["items"]->toStringNodeArray}]`
+  | MjAssignmentNode(aNode) =>
+    `${aNode["object"]->toStringSymbolNode} = ${aNode["value"]->toStringMathJsNode}`
   | MjConstantNode(cNode) => cNode["value"]->toStringValue
   | MjFunctionNode(fNode) => fNode->toStringFunctionNode
   | MjIndexNode(iNode) => iNode->toStringIndexNode
   | MjObjectNode(oNode) => oNode->toStringObjectNode
   | MjOperatorNode(opNode) => opNode->castOperatorNodeToFunctionNode->toStringFunctionNode
   | MjParenthesisNode(pNode) => `(${toStringMathJsNode(pNode["content"])})`
-  | MjSymbolNode(sNode) => sNode["name"]
+  | MjSymbolNode(sNode) => sNode->toStringSymbolNode
   }
 }
 and toStringResult = (rMathJsNode: result<mathJsNode, errorValue>): string =>