XCODX |

Nim Online Compiler & Interpreter

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Online Code Compiler
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Py main.py
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  Welcome to XCODX Online Compiler

  Quick Start:
  Ctrl+Enter  Run code
  Ctrl+S      Save / Download
  Ctrl+L      Clear output

  Select a language and start coding.
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About Nim

Nim reads like Python but compiles through C to small, fast native binaries, giving you indentation-based syntax with static typing and performance close to hand-written C. The language reached its mature 2.x series (Nim 2.0 shipped in 2023, with 2.2 following), and it runs in production at Status, whose Nimbus Ethereum client is written entirely in Nim. Its macro system operates on the abstract syntax tree, which makes it a favorite for developers who want metaprogramming without C++ template complexity. Here you can execute Nim in an interactive terminal straight from the browser: the program runs for real, output appears as it happens, and readLine calls wait for your keyboard input.

Hello World in Nim

import std/strutils

proc square(n: int): int = n * n

stdout.write("Enter your name: ")
let name = readLine(stdin).strip()
echo "Hello, ", name, "!"

stdout.write("Pick a number: ")
let n = parseInt(readLine(stdin).strip())
echo name, ", the square of ", n, " is ", square(n)

for i in 1..3:
  echo "Nim iteration ", i

When to use Nim

Nim fits developers who prototype in Python but need compiled speed: command-line tools, game scripting, scientific computing, and blockchain infrastructure like Status's Nimbus client. Students use it to learn static typing without heavy syntax, since procs, generics, and option types feel approachable coming from Python. Competitive programmers appreciate that Nim solutions run at C-like speed while staying short. It is also used to compile to JavaScript, so web developers experiment with sharing logic between backend binaries and frontend code.

Common questions

Does readLine(stdin) work interactively in this compiler?

Yes. Because the page attaches a real terminal to your running process, readLine(stdin) blocks exactly as it would locally. Your program prints its prompt, waits, and resumes the instant you type a line and press Enter, so multi-step console dialogs, menus, and parseInt-based numeric input all behave naturally.

Which Nim version and backend does this environment run?

Programs are built with a Nim 1.x/2.x era toolchain using the default C backend, then executed natively. That means real compiled performance rather than interpretation. Modern language features such as the strutils and sequtils modules, generics, and iterators are available; check compiler output if a very new 2.x-only feature errors.

Can I install Nimble packages in the online compiler?

No, the sandbox compiles one file without network access, so nimble install is unavailable. Nim's standard library is unusually broad, though: JSON parsing, regular expressions, OS routines, math, hashing, and unit testing via std/unittest are all built in, which covers most coursework and algorithm practice without external packages.

How Nim runs on XCODX

Sandbox filename
main.nim
Entry point
single main source file
Editor grammar
python
Reading stdin
readLine(stdin)
Input delivery
live WebSocket stream
Prompt flushing
flush manually before reading input
Compile limit
10 s
Run limit
3 s batch · up to 3 min live
Memory
256 MB per stage
Max source
50,000 characters

Default program on this page

echo "Hello from Nim!"
echo "Welcome to XCODX Online Compiler!"
let message = "Nim is efficient!"
echo message