Add precious workflow

.github/workflows/precious.yml

@@ -0,0 +1,31 @@
+name: Precious
+
+on:
+  push:
+    branches:
+      - 'main'
+  pull_request:
+  workflow_dispatch:
+
+jobs:
+  code-formatting:
+    runs-on: ubuntu-latest
+    name: Code Formatting
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+      - name: Install precious
+        run: ./bin/install-precious /usr/local/bin
+      - run: git diff --name-only --diff-filter=ACM upstream...
+      - name: Select files
+        id: select-files
+        run: |
+          if [[ -n "${{ github.event.pull_request.number }}" ]]; then
+            echo 'precious-args=--git-diff-from main' >> "$GITHUB_OUTPUT"
+          else
+            echo 'precious-args=--all' >> "$GITHUB_OUTPUT"
+          fi
+      - name: Lint files
+        run: precious lint ${{ steps.select-files.outputs.precious-args }}

bin/install-precious

@@ -0,0 +1,24 @@
+#!/usr/bin/env bash
+
+# This is for installing precious and other 3rd party libs needed for linting
+# in CI
+
+set -euo pipefail
+
+if [ -z "${1:-}" ]; then
+    echo "usage: ./bin/install-precious /path/to/bin/dir"
+    exit 1
+fi
+
+TARGET=$1
+export TARGET
+
+TARGET=$1
+export TARGET
+
+curl --silent --location \
+    https://raw.githubusercontent.com/houseabsolute/ubi/master/bootstrap/bootstrap-ubi.sh |
+    sh
+
+ubi --project houseabsolute/omegasort --in "$TARGET"
+ubi --project houseabsolute/precious --in "$TARGET"