diff --git a/.github/download-ROOT-source.rb b/.github/download-ROOT-source.rb
deleted file mode 100755
index 955da806..00000000
--- a/.github/download-ROOT-source.rb
+++ /dev/null
@@ -1,50 +0,0 @@
-#!/usr/bin/env ruby
-# download the ROOT source code
-
-if ARGV.empty?
-  $stderr.puts "USAGE: #{$0} [tag]"
-  exit 2
-end
-TAG  = ARGV.first
-REPO = 'root-project/ROOT'
-
-info = Hash.new
-case TAG
-when 'latest'
-  info = {
-    :api_url   => "https://api.github.com/repos/#{REPO}/releases/latest",
-    :jq_filter => '.tarball_url',
-  }
-else
-  info = {
-    :api_url   => "https://api.github.com/repos/#{REPO}/tags",
-    :jq_filter => ".[] | select (.name==\"#{TAG}\") | .tarball_url",
-  }
-end
-
-api_args = [
-  '--silent',
-  '-L',
-  '-H "Accept: application/vnd.github+json"',
-  '-H "X-GitHub-Api-Version: 2022-11-28"',
-  info[:api_url],
-]
-cmd = "curl #{api_args.join ' '} | jq -r '#{info[:jq_filter]}'"
-puts """API call:
-#{'='*82}
-#{cmd}
-#{'='*82}"""
-
-error = Proc.new do |msg|
-  $stderr.puts "ERROR: #{msg}"
-  exit 1
-end
-
-payload = `#{cmd}`
-error.call 'GitHub API call failure' unless $?.success?
-error.call "GitHub API call returned empty string, perhaps tag '#{TAG}' does not exist?" if payload.empty?
-url = payload.chomp
-puts "TARBALL URL = #{url}"
-
-puts "Downloading ROOT version '#{TAG}'..."
-exec "wget -nv --no-check-certificate --output-document root.tar.gz #{url}"
diff --git a/.github/download-ROOT-source.sh b/.github/download-ROOT-source.sh
new file mode 100755
index 00000000..c83ca582
--- /dev/null
+++ b/.github/download-ROOT-source.sh
@@ -0,0 +1,27 @@
+#!/usr/bin/env bash
+# download the ROOT source code
+
+set -euo pipefail
+
+if [ $# -ne 1 ]; then
+  echo "USAGE: $0 [TAG]" >&2
+  exit 1
+fi
+
+tag=$1
+curl_cmd='curl --silent -L -H "Accept: application/vnd.github+json" -H "X-GitHub-Api-Version: 2022-11-28"'
+
+echo "Download ROOT tag '$tag' from:"
+case $tag in
+  latest)
+    url=$($curl_cmd https://api.github.com/repos/root-project/ROOT/releases/latest | jq -r '.tarball_url')
+    ;;
+  *)
+    url=$($curl_cmd https://api.github.com/repos/root-project/ROOT/tags | jq -r '.[] | select (.name=="'$tag'") | .tarball_url')
+    ;;
+esac
+
+echo "  $url"
+[ -z "$url" ] && echo "ERROR: GitHub API call returned empty string, perhaps tag '$tag' does not exist?" && exit 1
+echo "downloading ..."
+wget -nv --no-check-certificate --output-document root.tar.gz $url
diff --git a/.github/install-dependency-packages.sh b/.github/install-dependency-packages.sh
index 318493e9..7e18e4ca 100755
--- a/.github/install-dependency-packages.sh
+++ b/.github/install-dependency-packages.sh
@@ -7,7 +7,6 @@ set -e
 ##############################
 GENERAL_PACKAGE_LIST_LINUX=(
   python
-  ruby
   gcc
   gcc-fortran
   clang
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index ca8c2e30..d44a3f1d 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -113,7 +113,7 @@ jobs:
       - name: download ROOT source code
         if: ${{ steps.cache.outputs.cache-hit != 'true' }}
         run: |
-          iguana_src/.github/download-ROOT-source.rb ${{ steps.key.outputs.root_version }}
+          iguana_src/.github/download-ROOT-source.sh ${{ steps.key.outputs.root_version }}
           tar xf $(ls -t *.gz | head -n1)
           ls -t
           mv -v $(ls -td root-* | head -n1) root_src
@@ -199,6 +199,51 @@ jobs:
           key: ${{ steps.key.outputs.key }}---${{ matrix.root_dep }}
           path: hipo.tar.zst
 
+  build_ruby_minver:
+    name: Build Minver Ruby
+    runs-on: ${{ inputs.runner }}
+    container:
+      image: ${{ inputs.container }}
+    outputs:
+      key: ${{ steps.key.outputs.key }}
+    steps:
+      - name: checkout iguana
+        if: ${{ inputs.verset == 'minver' }}
+        uses: actions/checkout@v4
+        with:
+          path: iguana_src
+      - name: key
+        if: ${{ inputs.verset == 'minver' }}
+        id: key
+        run: |
+          ver=$(iguana_src/meson/minimum-version.sh ruby)
+          echo ver=$ver >> $GITHUB_OUTPUT
+          echo key=ruby---${{ inputs.id }}---${ver}---$(date +%Y-week%U) >> $GITHUB_OUTPUT
+      - uses: actions/cache/restore@v4
+        if: ${{ inputs.verset == 'minver' }}
+        id: cache
+        with:
+          key: ${{ steps.key.outputs.key }}
+          path: ruby.tar.zst
+          lookup-only: true
+      - name: build ruby
+        if: ${{ steps.cache.outputs.cache-hit != 'true' && inputs.verset == 'minver' }}
+        run: |
+          iguana_src/.github/install-dependency-packages.sh ${{ inputs.runner }} ${{ inputs.verset }}
+          export RBENV_ROOT=$(pwd)/.rbenv
+          git clone https://github.com/rbenv/rbenv.git $RBENV_ROOT
+          eval "$($RBENV_ROOT/bin/rbenv init - bash)"
+          git clone https://github.com/rbenv/ruby-build.git $(rbenv root)/plugins/ruby-build
+          rbenv install ${{ steps.key.outputs.ver }}
+          rbenv global ${{ steps.key.outputs.ver }}
+          tar cavf ruby.tar.zst .rbenv
+      - uses: actions/cache/save@v4
+        if: ${{ steps.cache.outputs.cache-hit != 'true' && inputs.verset == 'minver' }}
+        id: cache_save
+        with:
+          key: ${{ steps.key.outputs.key }}
+          path: ruby.tar.zst
+
   # build and test Iguana
   #########################################################
 
@@ -208,6 +253,7 @@ jobs:
       - download_test_data
       - build_hipo
       - build_root
+      - build_ruby_minver
     runs-on: ${{ inputs.runner }}
     container:
       image: ${{ inputs.container }}
@@ -235,6 +281,26 @@ jobs:
       ###### system
       - name: install dependency packages
         run: iguana_src/.github/install-dependency-packages.sh ${{ inputs.runner }} ${{ inputs.verset }}
+      ###### ruby
+      - name: install ruby from linux package manager
+        if: ${{ inputs.id != 'macOS' && inputs.verset != 'minver' }}
+        run: pacman -S --noconfirm ruby
+      - name: install ruby from cached minver build
+        if: ${{ inputs.id != 'macOS' && inputs.verset == 'minver' }}
+        uses: actions/cache/restore@v4
+        with:
+          key: ${{ needs.build_ruby_minver.outputs.key }}
+          path: ruby.tar.zst
+      - name: source ruby from cached minver build
+        if: ${{ inputs.id != 'macOS' && inputs.verset == 'minver' }}
+        run: |
+          tar xf ruby.tar.zst
+          export RBENV_ROOT=$(pwd)/.rbenv
+          echo RBENV_ROOT=$RBENV_ROOT >> $GITHUB_ENV
+          eval "$($RBENV_ROOT/bin/rbenv init - bash)"
+          echo "ruby --version:"
+          ruby --version
+          echo PATH=$PATH >> $GITHUB_ENV
       ###### python bindings
       - name: install python bindings dependencies
         if: ${{ matrix.id == 'python' }}
@@ -289,6 +355,7 @@ jobs:
           echo '| --- | --- |' >> $GITHUB_STEP_SUMMARY
           echo "| \`hipo\` | ${{ env.hipo_ref }} |" >> $GITHUB_STEP_SUMMARY
           echo "| \`root\` | $(root --version 2>&1 | head -n1) |" >> $GITHUB_STEP_SUMMARY
+          echo "| \`ruby\` | $(ruby --version) |" >> $GITHUB_STEP_SUMMARY
           cat pkg_summary.md >> $GITHUB_STEP_SUMMARY
       ### build
       - name: meson setup
diff --git a/doc/setup.md b/doc/setup.md
index 55b5092c..4b186775 100644
--- a/doc/setup.md
+++ b/doc/setup.md
@@ -52,6 +52,12 @@ cmake --build build-hipo
 cmake --install build-hipo
 ```
 
+### 🟩 Optional: `ruby`: programming language
+<https://www.ruby-lang.org/en/>
+- Likely available in your package manager, likely as `ruby`
+- This is only needed if you intend to use Iguana with languages other than C++
+  - Bindings to other programming languages are generated by [`chameleon`](/src/chameleon), a local Ruby program
+
 ### 🟩 Optional: `ROOT`: Data analysis framework
 <https://root.cern.ch/>
 - ROOT is an **optional** dependency: some algorithms and test code depends on ROOT, but if you do not
diff --git a/meson.build b/meson.build
index 780cef9d..a37d5031 100644
--- a/meson.build
+++ b/meson.build
@@ -21,29 +21,40 @@ project_description = 'Implementation Guardian of Analysis Algorithms'
 
 # initialize binding languanges
 add_languages('fortran', native: false, required: get_option('bind_fortran'))
+use_chameleon = get_option('bind_fortran')
 
 # meson modules
 pkg = import('pkgconfig')
 fs = import('fs')
 
 # resolve dependencies
+prog_minver = find_program('meson' / 'minimum-version.sh')
 # NOTE: those that are typically installed by package managers should use `meson/minimum-version.sh`
 fmt_dep = dependency(
   'fmt',
   method: 'pkg-config',
-  version: run_command('meson' / 'minimum-version.sh', 'fmt', check: true).stdout().strip(),
+  version: '>=' + run_command(prog_minver, 'fmt', check: true).stdout().strip(),
 )
 yamlcpp_dep = dependency(
   'yaml-cpp',
   method: 'pkg-config',
-  version: run_command('meson' / 'minimum-version.sh', 'yaml-cpp', check: true).stdout().strip(),
+  version: '>=' + run_command(prog_minver, 'yaml-cpp', check: true).stdout().strip(),
+)
+hipo_dep = dependency(
+  'hipo4',
+  method: 'pkg-config',
+  version: '>=4.1.0'
 )
-hipo_dep = dependency('hipo4', method: 'pkg-config', version: '>=4.1.0')
 ROOT_dep = dependency(
   'ROOT',
   required: get_option('z_require_root'),
   method: 'cmake',
-  version: run_command('meson' / 'minimum-version.sh', 'ROOT', check: true).stdout().strip(),
+  version: '>=' + run_command(prog_minver, 'ROOT', check: true).stdout().strip(),
+)
+prog_ruby = find_program(
+  'ruby',
+  version: '>=' + run_command(prog_minver, 'ruby', check: true).stdout().strip(),
+  required: use_chameleon,
 )
 
 # list of dependencies
@@ -169,7 +180,6 @@ add_project_arguments(
 )
 
 # start chameleon
-use_chameleon = get_option('bind_fortran')
 if use_chameleon
   subdir('src/chameleon')
 endif
diff --git a/meson/minimum-version.sh b/meson/minimum-version.sh
index 823aef85..1d955ffc 100755
--- a/meson/minimum-version.sh
+++ b/meson/minimum-version.sh
@@ -1,12 +1,12 @@
 #!/usr/bin/env bash
 
 if [ $# -eq 0 ]; then
-  echo """USAGE: $0 [package] [command(default=meson)]
+  echo """USAGE: $0 [package] [command(default=ver)]
 
   package:  the package name; since this varies between package manager
             repositories, we prefer to use the name from that used by the CI
 
-  command:  meson   return a string for meson function \`dependency()\`
+  command:  ver     return the minimum version number
 
             ALA     return a URL for the Arch Linux Archive (ALA), for CI
                     https://archive.archlinux.org/
@@ -16,7 +16,7 @@ if [ $# -eq 0 ]; then
   exit 2
 fi
 dep=$1
-[ $# -ge 2 ] && cmd=$2 || cmd=meson
+[ $# -ge 2 ] && cmd=$2 || cmd=ver
 
 not_used() {
   [ "$cmd" = "$1" ] && echo "ERROR: command '$cmd' is not used for '$dep'" >&2 && exit 1
@@ -26,20 +26,25 @@ not_used() {
 
 case $dep in
   fmt)
-    result_meson='>=9.1.0'
+    result_ver='9.1.0'
     result_ala='https://archive.archlinux.org/packages/f/fmt/fmt-9.1.0-4-x86_64.pkg.tar.zst'
     not_used 'tag'
     ;;
   yaml-cpp)
-    result_meson='>=0.7.0'
+    result_ver='0.7.0'
     result_ala='https://archive.archlinux.org/packages/y/yaml-cpp/yaml-cpp-0.7.0-2-x86_64.pkg.tar.zst'
     not_used 'tag'
     ;;
   root|ROOT)
-    result_meson='>=6.28.12'
+    result_ver='6.28.12'
     result_tag='v6-28-12'
     not_used 'ALA'
     ;;
+  ruby)
+    result_ver='2.7.2'
+    not_used 'ALA'
+    not_used 'tag'
+    ;;
   *)
     echo "ERROR: dependency '$dep' is unknown" >&2
     exit 1
@@ -49,9 +54,9 @@ esac
 #############################################
 
 case $cmd in
-  meson) echo $result_meson ;;
-  ALA)   echo $result_ala   ;;
-  tag)   echo $result_tag   ;;
+  ver) echo $result_ver ;;
+  ALA) echo $result_ala ;;
+  tag) echo $result_tag ;;
   *)
     echo "ERROR: command '$cmd' is unknown" >&2
     exit 1
diff --git a/src/chameleon/meson.build b/src/chameleon/meson.build
index 44163b94..ebb37fde 100644
--- a/src/chameleon/meson.build
+++ b/src/chameleon/meson.build
@@ -4,5 +4,4 @@ chameleon_sources = files(
   'src' / 'bind_c.rb',
 )
 
-ruby = find_program('ruby', version: '>=3.0.0', required: use_chameleon)
-chameleon_gen = find_program(chameleon_sources[0], required: use_chameleon)
+prog_chameleon = find_program(chameleon_sources[0], required: use_chameleon)
diff --git a/src/iguana/algorithms/meson.build b/src/iguana/algorithms/meson.build
index 37186cf4..08fc9ac6 100644
--- a/src/iguana/algorithms/meson.build
+++ b/src/iguana/algorithms/meson.build
@@ -132,7 +132,7 @@ foreach algo : algo_dict
         input: [ algo_dir / 'Action.yaml', chameleon_sources ],
         output: [ target_name + '_bind.cc' ],
         command: [
-          chameleon_gen,
+          prog_chameleon,
           '--input', '@INPUT0@',
           '--output', '@OUTDIR@',
           '--prefix', target_name,