add zigup for easier zig toolchain installation (#6)

.zig-version

@@ -0,0 +1 @@
+0.12.0-dev.2541+894493549

README.md

@@ -166,6 +166,12 @@ The header file requires `zig.h` which is located in the `lib_dir` output by run
 
 This process should improve as https://github.com/ziglang/zig/issues/13528 is resolved.
 
+## Installing Zig
+
+Running `./zigup` will download and install the zig version specified in the `.zig-version` file. We recommend adding
+`$HOME/.zig/zig-latest` to your `PATH`.
+
+
 ## Python Library
 
 TODO: this library will be made available as a Python library using [Ziggy Pydust](https://github.com/fulcrum-so/ziggy-pydust).

zigup

@@ -0,0 +1,37 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+ZIG_HOME="${ZIG_HOME:-$HOME/.zig}"
+ZIG_LATEST="${ZIG_HOME}/zig-latest"
+mkdir -p "$ZIG_HOME"
+
+VERSION=$(cat ".zig-version" | tr -d '\n ')
+
+osOut="$(uname -s)"
+case "${osOut}" in
+    Linux*)     OS="linux";;
+    Darwin*)    OS="macos";;
+esac
+
+archOut="$(uname -m)"
+case "${archOut}" in
+    arm64*)     ARCH="aarch64";;
+    x86_64*)    ARCH="x86_64";;
+esac
+
+ARCH_VERSION="zig-${OS}-${ARCH}-${VERSION}"
+
+if [ ! -d "${ZIG_HOME}/${ARCH_VERSION}" ]
+then
+    echo "Downloading Zig version $VERSION"
+    curl -s -L "https://ziglang.org/builds/${ARCH_VERSION}.tar.xz" | tar -x -J -C "${ZIG_HOME}"
+else
+    echo "Zig version $VERSION already installed"
+fi
+
+# Always update the symlink to the requested version
+rm -f "$ZIG_LATEST"
+ln -s "${ZIG_HOME}/${ARCH_VERSION}" "$ZIG_LATEST"
+
+echo "Add ${ZIG_LATEST} to the \$PATH"