Languages and interop

Elide runs these languages from one binary:

Language	Status	Runs as	Start with	Interop
JavaScript	Supported	Script	`elide app.js`, `elide -s CODE`	Python: `--interop`; WASM: no flag
TypeScript	Supported	Script, types stripped	`elide app.ts`, `elide -l ts -s CODE`	As JavaScript
Python	Experimental	Python 3.13	`elide app.py`, `elide python -m MOD`	JavaScript: `--interop`
WebAssembly	Experimental	WASI Preview 1 command	`elide app.wasm` (`_start` or `_main`)	From JS/TS, no flag
Java, Kotlin	Supported	Compiled, run on the bundled JDK	`elide run Main.kt`, `elide.pkl` projects	None
Pkl	Supported	Configuration	`elide.pkl` manifests	None

elide info lists the languages in your binary; elide setup python adds Python. Per-language pages: JavaScript and TypeScript, Python, Java and Kotlin, WebAssembly.

elide --interop — Python calling JavaScript, JavaScript importing Python

 ~/demo  bat mod.py main.mjs
───────┬────────────────────────────────────────────────────────────────────────────────────────────
       │ File: mod.py
       │ Size: 58 B
───────┼────────────────────────────────────────────────────────────────────────────────────────────
   1   │ def greet(name):
   2   │     return f"Hello from Python, {name}!"
───────┴────────────────────────────────────────────────────────────────────────────────────────────
───────┬────────────────────────────────────────────────────────────────────────────────────────────
       │ File: main.mjs
       │ Size: 58 B
───────┼────────────────────────────────────────────────────────────────────────────────────────────
   1   │ import py from "./mod.py";
   2   │ 
   3   │ console.log(py.greet("Ada"));
───────┴────────────────────────────────────────────────────────────────────────────────────────────
 ~/demo  elide --interop main.mjs
Hello from Python, Ada!

Python calling JavaScript

python

# sum.py
from elide import js

print(js("[1,2,3].reduce((a,b)=>a+b,0)"))

utf-8 · python · Lines: 4

Terminal

bash

elide --interop python sum.py

text

utf-8 · text · Lines: 1

JavaScript importing Python

python

# mod.py
def greet(name):
    return f"hello {name}"

utf-8 · python · Lines: 3

javascript

// main.mjs
import mod from "./mod.py";
console.log(mod.greet("elide"));

utf-8 · javascript · Lines: 3

Terminal

bash

elide --interop main.mjs

text

hello elide

utf-8 · text · Lines: 1

The default export is the Python module. Use an .mjs entry.

Without `--interop`

Each program runs only its entry language, plus WebAssembly for JS/TS. Calls between languages fail:

Program	Error
`sum.py`	`ValueError: polyglot language 'js' not found`
`main.mjs`	`Cannot import 'mod.py': JavaScript entries run without Python. Re-run with --interop to use it.`

Pass --interop only to programs that call between languages. Under --interop, Python threads fail with Creating threads is not allowed.

JavaScript and WebAssembly

javascript

import { add } from "./math.wasm";
console.log(add(1, 2));

utf-8 · javascript · Lines: 2

.wasm imports and the WebAssembly API work in every JavaScript and TypeScript program. When Python is installed, modules that use SIMD instructions fail with Vector instructions are not enabled.

In the REPL

The REPL shares values across languages without --interop; see Interactive REPL.

Python calling JavaScript

JavaScript importing Python

Without --interop

JavaScript and WebAssembly

In the REPL

Samples

Without `--interop`