+ README

README.md

@@ -0,0 +1,44 @@
+# Introduction
+
+Local nix build for xo libraries.
+Intended for local development work, with source in immediate subdirectories.
+
+## Features
+
+- native c++
+- deterministic simulation
+- reflection
+- python bindings
+
+## Getting Started
+
+### Cmake build
+
+If `nix` is available, you probably prefer the nix build.
+Otherwise continue reading..
+
+The cmake build has two phases, because it needs to bootstrap
+generated `xo-cmake-config`, `xo-build` helpers.
+
+```
+$ cd xo
+$ PREFIX=/path/to/say/usr/local
+# phase 1
+$ cmake -B .build0 -S xo-cmake -DCMAKE_INSTALL_PREFIX=${PREFIX}
+$ cmake --build .build0
+$ cmake --install .build0
+# phase 2
+$ cmake -B .build -S . -DCMAKE_INSTALL_PREFIX=${PREFIX}
+$ cmake --build .build
+$ cmake --install .build
+```
+
+### Nix Build
+
+Nix build uses toplevel `default.nix`,
+along with top-level `pkgs/xo-foo.nix` for each subproject `foo`.
+It doesn't interact with toplevel `CMakeLists.txt`.
+
+```
+$ nix-build -A xo-userenv
+```