quick-start.md

Quick start

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From nothing to a C++23 project that imports a library from this index. Six commands, no build-system configuration.

1. Install mcpp

xlings install mcpp -y

Don't have xlings yet?

# Linux / macOS
curl -fsSL https://d2learn.org/xlings-install.sh | bash

# Windows · PowerShell
irm https://d2learn.org/xlings-install.ps1.txt | iex

2. Create and run a project

mcpp new hello
cd hello
mcpp run

The first build fetches the toolchain, so it takes a while; later builds are incremental. What the scaffold gives you:

hello/
├── mcpp.toml          ← project manifest
└── src/
    └── main.cpp       ← `import std;` works out of the box

3. Add a package from this index

mcpp add nlohmann.json@3.12.0

The name is the one shown on every package page — namespace.name. The command writes the dependency into your mcpp.toml:

[dependencies.nlohmann]
json = "3.12.0"

4. Use it

nlohmann.json is exposed as a C++23 module, so there is no header to find and no include path to configure:

// src/main.cpp
import std;
import nlohmann.json;

int main() {
    nlohmann::json j = { {"answer", 42}, {"list", {1, 2, 3}} };
    std::println("{}", j.dump());
}

Every package page tells you which line to write: import x; for module packages, #include <x> for the compat.* ports, and it is taken from this repository's own tests — code CI compiles.

5. Run it again

mcpp run

That is the whole loop: mcpp add → import → mcpp run.

Where to go next

Using packages

• Package types — the four library shapes in this index and what each one means for you as a consumer
• CN mirror — how packages resolve from the GitCode mirror in mainland China

Contributing a package

• Adding a package — the end-to-end procedure
• Repository & schema — descriptor fields, CI behaviour, how to reproduce lint locally

mcpp itself

• mcpp README — build system, toolchain management, the full command set
• mcpp.toml guide — version constraints, git references, local paths