MarkusNeusinger · MarkusNeusinger · May 16, 2026 · May 16, 2026 · May 16, 2026 · May 16, 2026
diff --git a/.github/actions/setup-r/action.yml b/.github/actions/setup-r/action.yml
@@ -0,0 +1,70 @@
+name: "Setup R + ggplot2"
+description: >-
+  Installs R, the system libraries needed for headless plot rendering, and the
+  package set used by anyplot's R implementations (ggplot2 + tidyverse helpers
+  + ragg device + dataset packages). Packages are restored from renv.lock at
+  the repository root so versions stay pinned.
+inputs:
+  r-version:
+    description: "R version to install"
+    required: false
+    default: "4.4.1"
+  working-directory:
+    description: "Directory containing renv.lock (defaults to the repo root)"
+    required: false
+    default: "."
+
+runs:
+  using: "composite"
+  steps:
+    - name: Install R
+      # r-lib/actions ships every sub-action from a single repo and tags them together;
+      # `@v2` is the maintained moving tag. Dependabot will pin to a SHA on first run.
+      uses: r-lib/actions/setup-r@v2
+      with:
+        r-version: ${{ inputs.r-version }}
+        use-public-rspm: true
+
+    # ragg needs libfreetype/libpng/libtiff/libjpeg headers; systemfonts needs
+    # libfontconfig1. These are pre-built on ubuntu-latest as binaries via
+    # Posit Package Manager, but keeping the apt fallback makes the action
+    # robust against future runner-image changes.
+    - name: Install system dependencies for ragg / systemfonts
+      shell: bash
+      run: |
+        sudo apt-get update
+        sudo apt-get install -y --no-install-recommends \
+          libcurl4-openssl-dev \
+          libssl-dev \
+          libxml2-dev \
+          libfontconfig1-dev \
+          libfreetype-dev \
+          libpng-dev \
+          libtiff5-dev \
+          libjpeg-dev \
+          libharfbuzz-dev \
+          libfribidi-dev
+
+    - name: Install R packages from renv.lock
+      uses: r-lib/actions/setup-renv@v2
+      with:
+        working-directory: ${{ inputs.working-directory }}
+      env:
+        # renv refuses to restore when per-package `Hash` fields are missing.
+        # The lockfile here is hand-written and intentionally omits hashes —
+        # reproducibility comes from the pinned Posit RSPM snapshot URL in
+        # renv.lock instead. Once a successful CI run populates hashes via
+        # renv::snapshot(), this flag can be dropped.
+        RENV_CONFIG_INSTALL_HASHES: "FALSE"
+
+    - name: Smoke-test ggplot2 renders a PNG
+      shell: bash
+      run: |
+        Rscript -e '
+          library(ggplot2); library(ragg)
+          tmp <- tempfile(fileext = ".png")
+          ggsave(tmp, ggplot(mtcars, aes(wt, mpg)) + geom_point(),
+                 device = ragg::agg_png, width = 4, height = 3, dpi = 100)
+          stopifnot(file.exists(tmp), file.info(tmp)$size > 0)
+          cat("ok: ", tmp, " (", file.info(tmp)$size, " bytes)\n", sep = "")
+        '
diff --git a/.github/workflows/bulk-generate.yml b/.github/workflows/bulk-generate.yml
@@ -28,6 +28,7 @@ on:
           - pygal
           - highcharts
           - letsplot
+          - ggplot2
       dry_run:
         description: "List what would be generated without executing"
         type: boolean
@@ -52,9 +53,9 @@ on:
         default: '{}'
 
 env:
-  ALL_LIBRARIES: "matplotlib seaborn plotly bokeh altair plotnine pygal highcharts letsplot"
+  ALL_LIBRARIES: "matplotlib seaborn plotly bokeh altair plotnine pygal highcharts letsplot ggplot2"
 
-# Serialise bulk-generate runs. Each run paces its own 9 dispatches with
+# Serialise bulk-generate runs. Each run paces its own dispatches with
 # `pace_seconds`; letting two runs overlap would interleave their
 # dispatches and stack the Claude queue, which is exactly what the pacing
 # exists to avoid. Second run waits for first to finish instead.

diff --git a/.github/workflows/daily-regen.yml b/.github/workflows/daily-regen.yml
@@ -284,7 +284,7 @@ jobs:
           MODEL: ${{ inputs.model || 'haiku' }}
           CHANGE_REQUESTS: ${{ steps.collect.outputs.change_requests }}
         run: |
-          echo "::notice::Dispatching bulk-generate for ${SPEC_ID} (all 9 libs, model=${MODEL})"
+          echo "::notice::Dispatching bulk-generate for ${SPEC_ID} (all libs, model=${MODEL})"
           gh workflow run bulk-generate.yml \
             --repo "${{ github.repository }}" \
             -f specification_id="${SPEC_ID}" \

diff --git a/.github/workflows/impl-generate.yml b/.github/workflows/impl-generate.yml
@@ -29,6 +29,7 @@ on:
           - pygal
           - highcharts
           - letsplot
+          - ggplot2
       issue_number:
         description: "Issue number (optional, for tracking)"
         required: false
@@ -111,16 +112,27 @@ jobs:
             MODEL="sonnet"
           fi
 
-          # Language: only python supported today. Future multi-language work will derive this per spec.
-          LANGUAGE="python"
+          # Derive LANGUAGE + EXT from LIBRARY. Mirrors core/constants.py LIBRARIES_METADATA;
+          # new non-Python entries get listed here too.
+          case "$LIBRARY" in
+            ggplot2)
+              LANGUAGE="r"
+              EXT=".R"
+              ;;
+            *)
+              LANGUAGE="python"
+              EXT=".py"
+              ;;
+          esac
 
           echo "specification_id=$SPEC_ID" >> $GITHUB_OUTPUT
           echo "library=$LIBRARY" >> $GITHUB_OUTPUT
           echo "language=$LANGUAGE" >> $GITHUB_OUTPUT
+          echo "ext=$EXT" >> $GITHUB_OUTPUT
           echo "issue_number=$ISSUE" >> $GITHUB_OUTPUT
           echo "model=$MODEL" >> $GITHUB_OUTPUT
 
-          echo "::notice::Generating $LANGUAGE/$LIBRARY for $SPEC_ID (issue: ${ISSUE:-none}, model: ${MODEL})"
+          echo "::notice::Generating $LANGUAGE/$LIBRARY for $SPEC_ID (issue: ${ISSUE:-none}, model: ${MODEL}, ext: ${EXT})"
 
       - name: Checkout repository
         uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd  # v6
@@ -189,7 +201,8 @@ jobs:
           gh issue edit "$ISSUE" --add-label "impl:${LIBRARY}:pending" 2>/dev/null || true
 
       # ========================================================================
-      # Setup: Python and dependencies
+      # Setup: Python and dependencies (always installed — needed for image
+      # processing + metadata writing even for non-Python implementations).
       # ========================================================================
       - name: Set up Python
         uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405  # v6
@@ -204,7 +217,8 @@ jobs:
           sudo apt-get update
           sudo apt-get install -y pngquant
 
-      - name: Install dependencies
+      - name: Install Python plotting dependencies
+        if: steps.inputs.outputs.language == 'python'
         env:
           LIBRARY: ${{ steps.inputs.outputs.library }}
         run: |
@@ -213,12 +227,25 @@ jobs:
           # Source of truth: pyproject.toml lib-${LIBRARY} extras
           uv pip install -e ".[lib-${LIBRARY}]" ruff pillow pyyaml
 
+      - name: Install Python helper deps (for non-Python implementations)
+        if: steps.inputs.outputs.language != 'python'
+        run: |
+          # ggplot2 / future non-Python libs render via their own runtime,
+          # but the pipeline still uses Python for metadata + image post-processing.
+          uv venv .venv
+          source .venv/bin/activate
+          uv pip install pillow pyyaml
+
       - name: Setup Chrome for Highcharts
         if: steps.inputs.outputs.library == 'highcharts'
         uses: browser-actions/setup-chrome@2e1d749697dd1612b833dba4a722266286fbefcd  # v2
         with:
           chrome-version: stable
 
+      - name: Setup R + ggplot2
+        if: steps.inputs.outputs.language == 'r'
+        uses: ./.github/actions/setup-r
+
       # ========================================================================
       # Generate: Create implementation branch and code
       # ========================================================================
@@ -244,9 +271,10 @@ jobs:
           SPEC_ID: ${{ steps.inputs.outputs.specification_id }}
           LANGUAGE: ${{ steps.inputs.outputs.language }}
           LIBRARY: ${{ steps.inputs.outputs.library }}
+          EXT: ${{ steps.inputs.outputs.ext }}
         run: |
           METADATA_FILE="plots/${SPEC_ID}/metadata/${LANGUAGE}/${LIBRARY}.yaml"
-          IMPL_FILE="plots/${SPEC_ID}/implementations/${LANGUAGE}/${LIBRARY}.py"
+          IMPL_FILE="plots/${SPEC_ID}/implementations/${LANGUAGE}/${LIBRARY}${EXT}"
 
           if [ -f "$METADATA_FILE" ] && [ -f "$IMPL_FILE" ]; then
             echo "is_regeneration=true" >> $GITHUB_OUTPUT
@@ -349,6 +377,7 @@ jobs:
             Variables for this run:
             - LANGUAGE: ${{ steps.inputs.outputs.language }}
             - LIBRARY: ${{ steps.inputs.outputs.library }}
+            - EXT: ${{ steps.inputs.outputs.ext }}
             - SPEC_ID: ${{ steps.inputs.outputs.specification_id }}
             - IS_REGENERATION: ${{ steps.existing.outputs.is_regeneration }}
 
@@ -368,6 +397,7 @@ jobs:
             Variables for this run:
             - LANGUAGE: ${{ steps.inputs.outputs.language }}
             - LIBRARY: ${{ steps.inputs.outputs.library }}
+            - EXT: ${{ steps.inputs.outputs.ext }}
             - SPEC_ID: ${{ steps.inputs.outputs.specification_id }}
             - IS_REGENERATION: ${{ steps.existing.outputs.is_regeneration }}
 
@@ -380,6 +410,7 @@ jobs:
           SPEC_ID: ${{ steps.inputs.outputs.specification_id }}
           LANGUAGE: ${{ steps.inputs.outputs.language }}
           LIBRARY: ${{ steps.inputs.outputs.library }}
+          EXT: ${{ steps.inputs.outputs.ext }}
           ISSUE: ${{ steps.issue.outputs.number }}
           BRANCH: ${{ steps.branch.outputs.branch }}
           MODEL: ${{ steps.inputs.outputs.model }}
@@ -424,39 +455,60 @@ jobs:
 
           mkdir -p "$METADATA_DIR"
 
-          # Get Python version (e.g., "3.13.1" from "Python 3.13.1")
+          # python_version = the Python interpreter that ran THIS pipeline (always 3.13).
+          # language_version = the implementation's own runtime — same as python_version for
+          # Python libs, the R version for ggplot2. The frontend renders language_version with
+          # the right language label, so we never mislabel R as "Python".
           PYTHON_VERSION=$(python3 --version 2>&1 | awk '{print $2}')
+          if [ "$LANGUAGE" = "r" ]; then
+            LANGUAGE_VERSION=$(Rscript -e 'cat(as.character(getRversion()))' 2>/dev/null || echo "unknown")
+          else
+            LANGUAGE_VERSION="$PYTHON_VERSION"
+          fi
 
-          # Get library version from pip (use explicit venv path)
+          # Get library version. Python libs read via `pip show`; R libs via
+          # packageVersion() inside Rscript. Names that differ between catalogue
+          # id and registry id are mapped explicitly.
           get_pip_version() {
             .venv/bin/pip show "$1" 2>/dev/null | grep -i "^Version:" | awk '{print $2}'
           }
+          get_r_version() {
+            Rscript -e "cat(as.character(packageVersion('$1')))" 2>/dev/null
+          }
 
-          case "$LIBRARY" in
-            letsplot)
-              LIBRARY_VERSION=$(get_pip_version "lets-plot")
-              ;;
-            highcharts)
-              LIBRARY_VERSION=$(get_pip_version "highcharts-core")
-              ;;
-            *)
-              LIBRARY_VERSION=$(get_pip_version "$LIBRARY")
-              ;;
-          esac
-
-          # Fallback if version is empty
-          if [ -z "$LIBRARY_VERSION" ]; then
-            echo "::warning::Could not get version for $LIBRARY, trying alternative method"
-            # Map library names to Python module names
+          if [ "$LANGUAGE" = "r" ]; then
+            LIBRARY_VERSION=$(get_r_version "$LIBRARY")
+          else
             case "$LIBRARY" in
-              letsplot) PYTHON_MODULE="lets_plot" ;;
-              plotnine) PYTHON_MODULE="plotnine" ;;
-              highcharts) PYTHON_MODULE="highcharts_core" ;;
-              *) PYTHON_MODULE="$LIBRARY" ;;
+              letsplot)
+                LIBRARY_VERSION=$(get_pip_version "lets-plot")
+                ;;
+              highcharts)
+                LIBRARY_VERSION=$(get_pip_version "highcharts-core")
+                ;;
+              *)
+                LIBRARY_VERSION=$(get_pip_version "$LIBRARY")
+                ;;
             esac
-            LIBRARY_VERSION=$(.venv/bin/python -c "import $PYTHON_MODULE; print(getattr($PYTHON_MODULE, '__version__', 'unknown'))" 2>/dev/null || echo "unknown")
+
+            # Fallback if version is empty
+            if [ -z "$LIBRARY_VERSION" ]; then
+              echo "::warning::Could not get version for $LIBRARY, trying alternative method"
+              # Map library names to Python module names
+              case "$LIBRARY" in
+                letsplot) PYTHON_MODULE="lets_plot" ;;
+                plotnine) PYTHON_MODULE="plotnine" ;;
+                highcharts) PYTHON_MODULE="highcharts_core" ;;
+                *) PYTHON_MODULE="$LIBRARY" ;;
+              esac
+              LIBRARY_VERSION=$(.venv/bin/python -c "import $PYTHON_MODULE; print(getattr($PYTHON_MODULE, '__version__', 'unknown'))" 2>/dev/null || echo "unknown")
+            fi
+          fi
+
+          if [ -z "$LIBRARY_VERSION" ]; then
+            LIBRARY_VERSION="unknown"
           fi
-          echo "::notice::Library version: $LIBRARY = $LIBRARY_VERSION"
+          echo "::notice::Library version: $LIBRARY = $LIBRARY_VERSION ($LANGUAGE runtime $LANGUAGE_VERSION, pipeline python $PYTHON_VERSION)"
 
           # Interactive libraries additionally produce HTML previews (one per theme)
           HAS_HTML="false"
@@ -475,6 +527,7 @@ jobs:
           run_id = ${{ github.run_id }}
           issue = int('$ISSUE' or '0')
           py_ver = '$PYTHON_VERSION'
+          lang_ver = '$LANGUAGE_VERSION'
           lib_ver = '$LIBRARY_VERSION'
           has_html = '$HAS_HTML' == 'true'
           metadata_file = '$METADATA_FILE'
@@ -508,6 +561,7 @@ jobs:
               'workflow_run': run_id,
               'issue': issue,
               'python_version': py_ver,
+              'language_version': lang_ver,
               'library_version': lib_ver,
               # Theme-aware preview URLs (Phase C). Both PNG variants are always emitted.
               'preview_url_light': f'{base_url}/plot-light.png',
@@ -527,7 +581,7 @@ jobs:
           git config user.name "github-actions[bot]"
           git config user.email "github-actions[bot]@users.noreply.github.com"
 
-          IMPL_FILE="plots/${SPEC_ID}/implementations/${LANGUAGE}/${LIBRARY}.py"
+          IMPL_FILE="plots/${SPEC_ID}/implementations/${LANGUAGE}/${LIBRARY}${EXT}"
 
           # Verify implementation file exists in the repository (Claude should have committed it)
           if ! git ls-files --error-unmatch "$IMPL_FILE" >/dev/null 2>&1; then
@@ -625,6 +679,7 @@ jobs:
           SPEC_ID: ${{ steps.inputs.outputs.specification_id }}
           LANGUAGE: ${{ steps.inputs.outputs.language }}
           LIBRARY: ${{ steps.inputs.outputs.library }}
+          EXT: ${{ steps.inputs.outputs.ext }}
           ISSUE: ${{ steps.issue.outputs.number }}
           BRANCH: ${{ steps.branch.outputs.branch }}
         run: |
@@ -643,7 +698,7 @@ jobs:
 
           Implements the **${LANGUAGE}/${LIBRARY}** version of \`${SPEC_ID}\`.
 
-          **File:** \`plots/${SPEC_ID}/implementations/${LANGUAGE}/${LIBRARY}.py\`"
+          **File:** \`plots/${SPEC_ID}/implementations/${LANGUAGE}/${LIBRARY}${EXT}\`"
 
           if [ -n "$ISSUE" ]; then
             BODY="${BODY}

diff --git a/.github/workflows/impl-merge.yml b/.github/workflows/impl-merge.yml
@@ -100,13 +100,25 @@ jobs:
           SPEC_ID=$(echo "$BRANCH" | cut -d'/' -f2)
           LIBRARY=$(echo "$BRANCH" | cut -d'/' -f3)
 
-          # Language: only python supported today. If future branches encode language,
-          # parse it from the branch name here.
-          LANGUAGE="python"
+          # Derive LANGUAGE + EXT from LIBRARY. Mirrors core/constants.py
+          # LIBRARIES_METADATA — extend this case when new non-Python libraries
+          # are added. We don't encode language in the branch name to keep
+          # existing branches and tooling working.
+          case "$LIBRARY" in
+            ggplot2)
+              LANGUAGE="r"
+              EXT=".R"
+              ;;
+            *)
+              LANGUAGE="python"
+              EXT=".py"
+              ;;
+          esac
 
           echo "specification_id=$SPEC_ID" >> $GITHUB_OUTPUT
           echo "library=$LIBRARY" >> $GITHUB_OUTPUT
           echo "language=$LANGUAGE" >> $GITHUB_OUTPUT
+          echo "ext=$EXT"           >> $GITHUB_OUTPUT
 
       - name: Validate PR completeness before merge
         if: steps.check.outputs.should_run == 'true'
@@ -115,13 +127,14 @@ jobs:
           SPEC_ID: ${{ steps.extract.outputs.specification_id }}
           LANGUAGE: ${{ steps.extract.outputs.language }}
           LIBRARY: ${{ steps.extract.outputs.library }}
+          EXT: ${{ steps.extract.outputs.ext }}
           BRANCH: ${{ steps.check.outputs.branch }}
           PR_NUM: ${{ steps.check.outputs.pr_number }}
         run: |
           # Fetch the PR branch to check its contents
           git fetch origin "$BRANCH"
 
-          IMPL_FILE="plots/${SPEC_ID}/implementations/${LANGUAGE}/${LIBRARY}.py"
+          IMPL_FILE="plots/${SPEC_ID}/implementations/${LANGUAGE}/${LIBRARY}${EXT}"
           META_FILE="plots/${SPEC_ID}/metadata/${LANGUAGE}/${LIBRARY}.yaml"
 
           # Check if implementation file exists on the PR branch