load stdlib runtime in playground

package.json

@@ -58,6 +58,7 @@
   },
   "scripts": {
     "dev": "next",
+    "res:watch": "rescript build -w",
     "build": "rescript && npm run update-index && next build",
     "test": "node scripts/test-examples.mjs && node scripts/test-hrefs.mjs",
     "reanalyze": "reanalyze -all-cmt .",

src/RenderPanel.res

@@ -10,14 +10,20 @@ let make = (~compilerState: CompilerManagerHook.state, ~clearLogs, ~runOutput) =
   React.useEffect(() => {
     if runOutput {
       switch compilerState {
-      | CompilerManagerHook.Ready({result: Comp(Success({js_code}))}) =>
+      | CompilerManagerHook.Ready({selected, result: Comp(Success({js_code}))}) =>
         clearLogs()
         open Babel
 
         let ast = Parser.parse(js_code, {sourceType: "module"})
-        let {entryPointExists, code} = PlaygroundValidator.validate(ast)
+        let {entryPointExists, code, imports} = PlaygroundValidator.validate(ast)
+        let imports = imports->Dict.mapValues(path => {
+          let filename = path->String.sliceToEnd(~start=9) // the part after "./stdlib/"
+          CompilerManagerHook.CdnMeta.getStdlibRuntimeUrl(selected.id, filename)
+        })
 
-        entryPointExists ? code->wrapReactApp->EvalIFrame.sendOutput : EvalIFrame.sendOutput(code)
+        entryPointExists
+          ? code->wrapReactApp->EvalIFrame.sendOutput(imports)
+          : EvalIFrame.sendOutput(code, imports)
         setValidReact(_ => entryPointExists)
       | _ => ()
       }

src/bindings/Babel.res

@@ -10,14 +10,48 @@ module Ast = {
   @tag("type")
   type expression = ObjectExpression({properties: array<objectProperties>})
 
-  type variableDeclarator = {
-    @as("type") type_: string,
-    id: lval,
-    init?: Null.t<expression>,
+  module VariableDeclarator = {
+    @tag("type")
+    type t = VariableDeclarator({id: lval, init?: Null.t<expression>})
   }
+  module Specifier = {
+    @tag("type")
+    type t =
+      | ImportSpecifier({local: lval})
+      | ImportDefaultSpecifier({local: lval})
+      | ImportNamespaceSpecifier({local: lval})
+  }
+
+  module StringLiteral = {
+    @tag("type")
+    type t = StringLiteral({value: string})
+  }
+
+  module VariableDeclaration = {
+    @tag("type")
+    type t = VariableDeclaration({kind: string, declarations: array<VariableDeclarator.t>})
+  }
+
+  module ImportDeclaration = {
+    @tag("type")
+    type t = ImportDeclaration({specifiers: array<Specifier.t>, source: StringLiteral.t})
+  }
+
+  module Identifier = {
+    @tag("type")
+    type t = Identifier({mutable name: string})
+  }
+
   @tag("type")
-  type node = VariableDeclaration({kind: string, declarations: array<variableDeclarator>})
-  type nodePath = {node: node}
+  type node =
+    | ...StringLiteral.t
+    | ...Specifier.t
+    | ...VariableDeclarator.t
+    | ...VariableDeclaration.t
+    | ...ImportDeclaration.t
+    | ...Identifier.t
+
+  type nodePath<'nodeType> = {node: 'nodeType}
 }
 
 module Parser = {
@@ -30,7 +64,7 @@ module Traverse = {
 }
 
 module Generator = {
-  @send external remove: Ast.nodePath => unit = "remove"
+  @send external remove: Ast.nodePath<'nodeType> => unit = "remove"
 
   type t = {code: string}
   @module("@babel/generator") external generator: Ast.t => t = "default"
@@ -40,26 +74,42 @@ module PlaygroundValidator = {
   type validator = {
     entryPointExists: bool,
     code: string,
+    imports: Dict.t<string>,
   }
 
   let validate = ast => {
     let entryPoint = ref(false)
+    let imports = Dict.make()
 
     let remove = nodePath => Generator.remove(nodePath)
     Traverse.traverse(
       ast,
       {
-        "ImportDeclaration": remove,
+        "ImportDeclaration": (
+          {
+            node: ImportDeclaration({specifiers, source: StringLiteral({value: source})}),
+          } as nodePath: Ast.nodePath<Ast.ImportDeclaration.t>,
+        ) => {
+          if source->String.startsWith("./stdlib") {
+            switch specifiers {
+            | [ImportNamespaceSpecifier({local: Identifier({name})})] =>
+              imports->Dict.set(name, source)
+            | _ => ()
+            }
+          }
+          remove(nodePath)
+        },
         "ExportNamedDeclaration": remove,
-        "VariableDeclaration": (nodePath: Ast.nodePath) => {
-          switch nodePath.node {
-          | VariableDeclaration({declarations}) if Array.length(declarations) > 0 =>
+        "VariableDeclaration": (
+          {node: VariableDeclaration({declarations})}: Ast.nodePath<Ast.VariableDeclaration.t>,
+        ) => {
+          if Array.length(declarations) > 0 {
             let firstDeclaration = Array.getUnsafe(declarations, 0)
 
-            switch (firstDeclaration.id, firstDeclaration.init) {
-            | (Identifier({name}), Some(init)) if name === "App" =>
-              switch init->Null.toOption {
-              | Some(ObjectExpression({properties})) =>
+            switch firstDeclaration {
+            | VariableDeclarator({id: Identifier({name}), init}) if name === "App" =>
+              switch init {
+              | Value(ObjectExpression({properties})) =>
                 let foundEntryPoint = properties->Array.find(property => {
                   switch property {
                   | ObjectProperty({
@@ -74,12 +124,10 @@ module PlaygroundValidator = {
               }
             | _ => ()
             }
-          | _ => ()
           }
         },
       },
     )
-
-    {entryPointExists: entryPoint.contents, code: Generator.generator(ast).code}
+    {entryPointExists: entryPoint.contents, imports, code: Generator.generator(ast).code}
   }
 }

src/bindings/Webapi.res

@@ -27,6 +27,9 @@ module Element = {
   @send
   external postMessage: (contentWindow, string, ~targetOrigin: string=?) => unit = "postMessage"
 
+  @send
+  external postMessageAny: (contentWindow, 'a, ~targetOrigin: string=?) => unit = "postMessage"
+
   module Style = {
     @scope("style") @set external width: (Dom.element, string) => unit = "width"
     @scope("style") @set external height: (Dom.element, string) => unit = "height"

src/common/CompilerManagerHook.res

@@ -40,6 +40,9 @@ module CdnMeta = {
 
   let getLibraryCmijUrl = (version, libraryName: string): string =>
     `https://cdn.rescript-lang.org/${Semver.toString(version)}/${libraryName}/cmij.js`
+
+  let getStdlibRuntimeUrl = (version, filename) =>
+    `https://cdn.rescript-lang.org/${Semver.toString(version)}/compiler-builtins/stdlib/${filename}`
 }
 
 module FinalResult = {

src/common/CompilerManagerHook.resi

@@ -27,6 +27,10 @@ type ready = {
   result: FinalResult.t,
 }
 
+module CdnMeta: {
+  let getStdlibRuntimeUrl: (Semver.t, string) => string
+}
+
 type state =
   | Init
   | SetupFailed(string)

src/common/EvalIFrame.res

@@ -18,7 +18,6 @@ let srcDoc = `
         <script type="importmap">
           {
             "imports": {
-              "@jsxImportSource": "https://esm.sh/react@${reactVersion}",
               "react-dom/client": "https://esm.sh/react-dom@${reactVersion}/client",
               "react": "https://esm.sh/react@${reactVersion}",
               "react/jsx-runtime": "https://esm.sh/react@${reactVersion}/jsx-runtime"
@@ -36,11 +35,14 @@ let srcDoc = `
           window.JsxRuntime = JsxRuntime;
         </script>
         <script>
-          window.addEventListener("message", (event) => {
+          window.addEventListener("message", async (event) => {
             try {
               // https://rollupjs.org/troubleshooting/#avoiding-eval
-              const eval2 = eval;
-              eval2(event.data);
+              const imports = {};
+              for (const [key, path] of Object.entries(event.data.imports)) {
+                imports[key] = await import(path);
+              }
+              (Function(...Object.keys(imports), event.data.code))(...Object.values(imports));
             } catch (err) {
               console.error(err);
             }
@@ -67,15 +69,20 @@ let srcDoc = `
     </html>
   `
 
-let sendOutput = code => {
+type message = {
+  code: string,
+  imports: Dict.t<string>,
+}
+
+let sendOutput = (code, imports) => {
   open Webapi
 
   let frame = Document.document->Element.getElementById("iframe-eval")
 
   switch frame {
   | Value(element) =>
     switch element->Element.contentWindow {
-    | Some(win) => win->Element.postMessage(code, ~targetOrigin="*")
+    | Some(win) => win->Element.postMessageAny({code, imports}, ~targetOrigin="*")
     | None => Console.error("contentWindow not found")
     }
   | Null | Undefined => Console.error("iframe not found")