onedice-cpp-lib

A dependency-free C++17 implementation of the OneDice V1 unified dice-string standard — the C++ counterpart to the official Python / Kotlin / Rust / TypeScript reference libraries.

Usage

#include "onedice/onedice.h"

onedice::RD dice("(1d8+2d100)*1d10");
if (dice.roll() == 0) {
    long long result = dice.resInt();   // e.g. 1296
    std::string how  = dice.detail();   // human-readable breakdown
}

Or the one-shot form:

auto r = onedice::eval("4d6kh3");       // DND ability score
if (r.ok) std::cout << r.value << " " << r.detail;

Evaluation failures are classified so callers can build a safe parser chain:

auto r = onedice::eval(expr);
if (!r.ok && r.errorKind == onedice::ErrorKind::UnsupportedSyntax) {
    // It is safe to let another expression engine try the input.
} else if (!r.ok) {
    // Evaluation failed (for example division by zero); do not reroll elsewhere.
}

You can inject your own RNG (e.g. a seeded or session-shared generator):

onedice::RD d("3d6");
d.setRandom([](long long faces){ return /* 1..faces */; });

Supported (V1 core)

Feature	Syntax
Arithmetic & precedence	+ - * / ^ ( ), x as *
Multi-face dice	AdB (face defaults configurable)
Keep highest / lowest	kh kl dh dl, and d-suffix k/q
Clamp	max / min
Penalty / bonus (COC)	ApB / AbB
Infinite adding pool	AaBkCqDmE
Double-cross pool	AcBmC
FATE / Fudge	Af, AdfB, f
Comparison / bitwise	< >, & |
Tuples	[a,b,c]

Not yet implemented (roadmap)

?: ternary, $t temp variables, lp loop, sp slice, tp eject, factorial, xo explode, environment variables. Contributions welcome.

Build

cmake -B build -S . && cmake --build build
./build/onedice-example     # runs the smoke test

Integrate into your project via CMake:

add_subdirectory(onedice-cpp-lib)
target_link_libraries(your_target PRIVATE onedice::onedice)

License

MIT (see LICENSE), matching the OneDice project.