T81 Foundation

T81 C++ Quickstart Guide

This page is the C++ portal: it describes how to bootstrap the deterministic ledger (build, tests, code, docs) so every artifact remains reproducible.

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1. Prerequisites

• A C++23-capable compiler (temporary fallback lane: -DT81_USE_CXX23=OFF)
• CMake 3.16+
• Ninja (recommended) or Make

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2. Build and Test

The project uses a standard CMake workflow.

# 1. Clone the repository
git clone https://github.com/t81dev/t81-foundation.git
cd t81-foundation

# 2. Configure the build (add -G Ninja if you prefer)
cmake -S . -B build -DCMAKE_BUILD_TYPE=Release

# 3. Build libraries, examples, tests, and docs
cmake --build build --parallel

# 4. Run the CTest test suite
ctest --test-dir build --output-on-failure

A successful run will show all unit tests passing.

To validate the temporary compatibility lane explicitly:

cmake -S . -B build-cxx20 -DCMAKE_BUILD_TYPE=Release -DT81_USE_CXX23=OFF
cmake --build build-cxx20 --parallel
ctest --test-dir build-cxx20 --output-on-failure

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3. “Hello Ternary” Example

The core of the numeric system is the T81Int class. Here is a minimal example of how to use it.

#include <t81/core/T81Int.hpp>
#include <iostream>

int main() {
    using t81::core::T81Int;

    // Create two 8-trit integers from decimal values
    T81Int<8> a{5};
    T81Int<8> b{-3};

    // Arithmetic works as expected
    auto sum = a + b; // 5 + (-3) = 2

    // Convert back to a standard C++ integer for printing
    std::cout << "Sum (decimal): " << sum.to_binary<int64_t>() << std::endl;

    // Print the native balanced ternary representation
    std::cout << "Sum (ternary): " << sum.str() << std::endl;

    return 0;
}

To compile and run this, you would link against the t81_core library.

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4. Where to Go Next

• To understand the code’s structure: Read the ../../explanation/ARCHITECTURE.md to see how the different libraries (t81_core, t81_lang_frontend, etc.) fit together in the deterministic ledger.
• To find a task to work on: See the prioritized list of needed contributions in TASKS.md.
• To understand the onboarding flow: See ../../records/archive/temporal-guides/tutorials/onboarding.md.
• To explore the API: Generate the Doxygen documentation by running cmake --build build --target docs and opening build/api/html/index.html.

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5. Notes & Caveats

• Status evolves quickly: prefer ../../reference/system-status.md and ../explanation/ANALYSIS.md for current implementation parity against spec.
• Use the deterministic ritual: run configure/build/test exactly as documented above before trusting local behavior.
• Compatibility lane: C++23 is default; run the optional C++20 lane (-DT81_USE_CXX23=OFF) when validating cross-toolchain compatibility.

For a detailed status of all components, see the System Status Report.

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