Installing the Dragon SDK

The Dragon SDK is the Mica compiler’s backend, published as a deliverable: one C header and one static archive, behind which sit control-flow analysis, an SSA middle-end, storage placement, register allocation, and native emission for x86-64 and ARM64. A compiler front end written in any language hands it an intermediate-code unit and gets optimized native code back — the same engine that compiles Mica, not a reduced version of it. The announcement tells the whole story, and Build a compiler with Mica is the guided course built on it. This page is the practical part: the licence, the download, and the check that it works.

The SDK stands alone — a frontend written in C never needs the Mica compiler installed. What it does need is the Dragon runtime, the mica-dragon-rt package: the floor the programs your frontend produces start in and call. The standard library above that floor is yours to bring — a frontend ships its own, the way the course’s PL/0 compiler ships its one-function pl0-stdlib.c, or imports straight from libc. The SDK package therefore depends on mica-dragon-rt and pins the exact version it was built with, so apt keeps the pair consistent; the Mica compiler is suggested only for writing your frontend in Mica.

The licence, before the download

The compiler and the SDK ship under different licences, and this is the one place in the Mica ecosystem where that matters. Mica itself is free for every purpose, commercial work included — that does not change. The Dragon SDK is licensed under the PolyForm Noncommercial License 1.0.0:

Anyone may try it. Install it, read the header, write a front end, run the course — for study or your own interest, that is inside the free grant. If it is work for a company, including internal work toward a commercial product, write to us first and we will sort it out with you. The full licence text installs at /usr/share/doc/mica-dragon-sdk/copyright.

Zero-install: the container

The container image deliberately does not carry the SDK — taking a licence should be a decision, not something that happens to you. One command inside the image prints the terms, waits for your answer, and then installs the two files:

mica-install-sdk

Everything below is the native installation.

Download

The licence is not the compiler's. Mica itself is free for every purpose, commercial work included. The Dragon SDK is licensed under the PolyForm Noncommercial License 1.0.0: free for research, teaching, personal study, hobby projects, and for educational, charitable, public research and government institutions — and any commercial use requires a separate written agreement. Write to info@mica-dev.com before you begin, and we will sort it out with you. Downloading it means accepting those terms.

Version 7.2.0, built from commit 9ebcec52. Verify a download with sha256sum against the hash above.

Install

# from the directory holding both .deb files - no compiler package required
sudo apt install ./mica-dragon-sdk_<version>_<arch>.deb ./mica-dragon-rt_<version>_<arch>.deb

The SDK depends on the Dragon runtime at the same version, so apt refuses a mismatch instead of letting an archive meet a floor that believes something else. If the Mica compiler is installed too, its own mica-dragon-rt dependency is the same package — one floor serves every road. When you upgrade any of them, upgrade all in the same command.

Check it worked

The smallest honest check is a C program that opens a Dragon session and closes it again. Save this as probe.c:

#include <mica_dragon.h>
#include <stdio.h>

int main(void) {
    drg_ctx session;
    if (dragon_context_new(&session) != 0) return 1;
    dragon_context_free(session);
    puts("dragon: ready");
    return 0;
}

and build it against the archive — <arch> is amd64 or arm64, matching your machine:

gcc -std=c23 probe.c /usr/lib/libmicadragon-<arch>.a -lpthread -o probe
./probe

You should see dragon: ready. From here, the course’s chapter 2 builds and runs a complete compiler against the same two files.

From Mica the engine is reached by import instead — imp ContextNew, UnitNew : dragon; — and no header is involved: the dragon surface is embedded in the compiler, so a Mica front end compiles and type-checks without the SDK installed. Only the link asks for the archive, and names the missing file if it is not there. What that surface contains is the installed dragon-engine.json — the Mica-side counterpart of reading the header.

What gets installed

The SDK pair on disk — and, when the Mica compiler is installed beside them, its two files complete the picture:

/usr/lib/
├── libmicadragon-<arch>.a                     the backend engine         (mica-dragon-sdk)
├── libmicadragon-rt-<arch>.a                  the Dragon runtime         (mica-dragon-rt)
├── libmicadragon-rt-fixedarena-<arch>.a         … freestanding memory class
├── libmicadragon-rt-mc-<arch>.a                 … multicore tasking
└── libmicadragon-rt-fixedarena-mc-<arch>.a      … both

/usr/include/
└── mica_dragon.h                              the whole consumer surface, one header

/usr/share/doc/
├── mica-dragon-rt/copyright                   Mica Runtime License 1.0
└── mica-dragon-sdk/
    ├── copyright                              PolyForm Noncommercial 1.0.0
    └── dragon-engine.json                     the curated `dragon` import surface, as a
                                               file you can read — held byte-identical to
                                               what the compiler embeds

only with the mica package installed beside them:
/usr/bin/mica                                  the compiler driver        (mica)
/usr/lib/mica-stdlib-<arch>.a                  Mica's own standard library (mica)

Nothing else — no shared libraries, no daemon, no configuration. Your frontend links the engine archive; the programs it emits link the runtime archives plus whatever standard library you ship. Removing the packages removes everything.

See also

• The Dragon SDK announcement — what it is and why we published it
• Build a compiler with Mica — the eleven-chapter course on the shipped example
• Installing Mica — the compiler this package installs beside
• Licensing — the compiler’s own licence, free for any use