Added lazy_py_modules

docs/README.md

@@ -372,11 +372,25 @@ The module is registered within the interpreter as *JS* module and it offers var
 
 ### Main exports
 
-| name          | example                                | description |
-| :------------ | :------------------------------------- | :---------- |
-| XWorker       | `from polyscript import XWorker`       | described in the [XWorker](#xworker) part. |
-| currentScript | `from polyscript import currentScript` | it's an explicit, always correct, reference to the current node running the generic script code. |
-| js_modules    | `from polyscript import js_modules`    | described in the [Extra config Features](#extra-config-features) part. |
+| name            | example                                  | description |
+| :-------------- | :--------------------------------------- | :---------- |
+| XWorker         | `from polyscript import XWorker`         | described in the [XWorker](#xworker) part. |
+| currentScript   | `from polyscript import currentScript`   | it's an explicit, always correct, reference to the current node running the generic script code. |
+| js_modules      | `from polyscript import js_modules`      | described in the [Extra config Features](#extra-config-features) part. |
+| lazy_py_modules | `from polyscript import lazy_py_modules` | allows, only in *Python* related interpreters, and without needing static config entries, to import lazily any available module.
+
+
+#### lazy_py_modules
+
+```html
+<script type="pyodide" async>
+  from polyscript import lazy_py_modules
+
+  matplotlib, regex, = await lazy_py_modules("matplotlib", "regex")
+
+  print(matplotlib, regex)
+</script>
+```
 
 
 ### Worker exports

esm/interpreter/_python.js

@@ -1,9 +1,17 @@
 import { dedent } from '../utils.js';
 import { io } from './_io.js';
 
+export const loader = new WeakMap();
+
 // REQUIRES INTEGRATION TEST
 /* c8 ignore start */
 export const registerJSModule = (interpreter, name, value) => {
+    if (name === 'polyscript') {
+        value.lazy_py_modules = async (...packages) => {
+            await loader.get(interpreter)(packages);
+            return packages.map(name => interpreter.pyimport(name));
+        };
+    }
     interpreter.registerJsModule(name, value);
 };
 

esm/interpreter/micropython.js

@@ -1,6 +1,6 @@
 // import fetch from '@webreflection/fetch';
 import { fetchFiles, fetchJSModules, fetchPaths, writeFile } from './_utils.js';
-import { getFormat, registerJSModule, run, runAsync, runEvent } from './_python.js';
+import { getFormat, loader, registerJSModule, run, runAsync, runEvent } from './_python.js';
 import { stdio, buffered } from './_io.js';
 import mip from '../python/mip.js';
 import zip from '../zip.js';
@@ -20,17 +20,15 @@ export default {
         });
         url = url.replace(/\.m?js$/, '.wasm');
         const interpreter = await get(loadMicroPython({ linebuffer: false, stderr, stdout, url }));
+        const py_imports = importPackages.bind(interpreter);
+        loader.set(interpreter, py_imports);
         if (config.files) await fetchFiles(this, interpreter, config.files);
         if (config.fetch) await fetchPaths(this, interpreter, config.fetch);
         if (config.js_modules) await fetchJSModules(config.js_modules);
 
         // Install Micropython Package
         this.writeFile(interpreter, './mip.py', mip);
-        if (config.packages){
-            const mpyPackageManager = interpreter.pyimport('mip');
-            for (const mpyPackage of config.packages)
-                mpyPackageManager.install(mpyPackage);
-        }
+        if (config.packages) await py_imports(config.packages);
         return interpreter;
     },
     registerJSModule,
@@ -92,4 +90,10 @@ export default {
         return writeFile(fs, path, buffer);
     },
 };
+
+async function importPackages(packages) {
+    const mpyPackageManager = this.pyimport('mip');
+    for (const mpyPackage of packages)
+        mpyPackageManager.install(mpyPackage);
+}
 /* c8 ignore stop */

esm/interpreter/pyodide.js

@@ -1,7 +1,7 @@
 import { create } from 'gc-hook';
 
 import { RUNNING_IN_WORKER, fetchFiles, fetchJSModules, fetchPaths, writeFile } from './_utils.js';
-import { getFormat, registerJSModule, run, runAsync, runEvent } from './_python.js';
+import { getFormat, loader, registerJSModule, run, runAsync, runEvent } from './_python.js';
 import { stdio } from './_io.js';
 
 const type = 'pyodide';
@@ -89,15 +89,12 @@ export default {
         const interpreter = await get(
             loadPyodide({ stderr, stdout, indexURL }),
         );
+        const py_imports = importPackages.bind(interpreter);
+        loader.set(interpreter, py_imports);
         if (config.files) await fetchFiles(this, interpreter, config.files);
         if (config.fetch) await fetchPaths(this, interpreter, config.fetch);
         if (config.js_modules) await fetchJSModules(config.js_modules);
-        if (config.packages) {
-            await interpreter.loadPackage('micropip');
-            const micropip = await interpreter.pyimport('micropip');
-            await micropip.install(config.packages, { keep_going: true });
-            micropip.destroy();
-        }
+        if (config.packages) await py_imports(config.packages);
         return interpreter;
     },
     registerJSModule,
@@ -120,4 +117,12 @@ export default {
         return writeFile({ FS, PATH, PATH_FS }, path, buffer);
     },
 };
+
+// exposed utility to import packages via polyscript.lazy_py_modules
+async function importPackages(packages) {
+    await this.loadPackage('micropip');
+    const micropip = this.pyimport('micropip');
+    await micropip.install(packages, { keep_going: true });
+    micropip.destroy();
+}
 /* c8 ignore stop */

package.json

@@ -90,6 +90,6 @@
         "to-json-callback": "^0.1.1"
     },
     "worker": {
-        "blob": "sha256-NuQY85dugu2Ks8ubOmDiR+aw7eOW0CQvTfRQIknWkPk="
+        "blob": "sha256-8x1Yej68/ZpJysyfYgjrdqQ+hQmhGh7Pol8qLUUi/g4="
     }
 }

test/py_modules.html

@@ -0,0 +1,19 @@
+<!doctype html>
+<html lang="en">
+    <head>
+        <meta charset="UTF-8">
+        <meta name="viewport" content="width=device-width,initial-scale=1.0">
+        <title>python modules</title>
+        <link rel="stylesheet" href="style.css">
+        <script type="module" src="../dist/index.js"></script>
+    </head>
+    <body>
+        <script type="pyodide" async>
+          from polyscript import lazy_py_modules
+
+          matplotlib, regex, = await lazy_py_modules("matplotlib", "regex")
+
+          print(matplotlib, regex)
+        </script>
+    </body>
+</html>