Add some useful gems for ruby code

11 files changed, 336 insertions, 124 deletions

diff --git a/.gitignore b/.gitignore
index bcbf68f..d06ffb4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,6 +3,10 @@ jit/
 .cache/
 /compile_commands.json
 
+# Tree-sitter.
 *.o
 *.so
 node_modules/
+
+# Ruby.
+/vendor/
diff --git a/.rubocop.yml b/.rubocop.yml
new file mode 100644
index 0000000..d69ffc7
--- /dev/null
+++ b/.rubocop.yml
@@ -0,0 +1,30 @@
+plugins:
+  - rubocop-rake
+
+AllCops:
+  TargetRubyVersion: 4.0
+  NewCops: enable
+  SuggestExtensions: false
+  Include:
+    - 'Rakefile'
+    - 'rakelib/**/*'
+
+Metrics/BlockLength:
+  AllowedMethods:
+    - namespace
+    - task
+
+Layout/ArgumentAlignment:
+  EnforcedStyle: with_fixed_indentation
+
+Layout/ParameterAlignment:
+  EnforcedStyle: with_fixed_indentation
+
+Layout/ArrayAlignment:
+  EnforcedStyle: with_fixed_indentation
+
+Layout/MultilineMethodCallIndentation:
+  EnforcedStyle: indented
+
+Layout/MultilineOperationIndentation:
+  EnforcedStyle: indented
diff --git a/Gemfile b/Gemfile
new file mode 100644
index 0000000..42188c7
--- /dev/null
+++ b/Gemfile
@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+source 'https://rubygems.org'
+
+gem 'rake', '~> 13.4'
+gem 'rubocop', '~> 1.91'
+gem 'rubocop-rake', '~> 0.7'
+
+gem 'faraday', '~> 2.14'
+gem 'faraday-follow_redirects', '~> 0.5'
+
+gem 'term-ansicolor', '~> 1.11'
diff --git a/Gemfile.lock b/Gemfile.lock
new file mode 100644
index 0000000..1c40795
--- /dev/null
+++ b/Gemfile.lock
@@ -0,0 +1,139 @@
+GEM
+  remote: https://rubygems.org/
+  specs:
+    ast (2.4.3)
+    bigdecimal (4.1.3)
+    erb (6.0.7)
+    faraday (2.14.4)
+      faraday-net_http (>= 2.0, < 3.5)
+      json
+      logger
+    faraday-follow_redirects (0.5.0)
+      faraday (>= 1, < 3)
+    faraday-net_http (3.4.4)
+      net-http (~> 0.5)
+    io-console (0.9.4)
+    irb (1.18.0)
+      pp (>= 0.6.0)
+      prism (>= 1.3.0)
+      rdoc (>= 4.0.0)
+      reline (>= 0.4.2)
+    json (3.0.2)
+    language_server-protocol (3.17.0.6)
+    lint_roller (1.1.0)
+    logger (1.7.0)
+    mize (0.6.1)
+    net-http (0.9.1)
+      uri (>= 0.11.1)
+    parallel (2.3.0)
+    parser (3.3.12.0)
+      ast (~> 2.4.1)
+      racc
+    pp (0.6.4)
+      prettyprint
+    prettyprint (0.2.0)
+    prism (1.9.0)
+    racc (1.8.1)
+    rainbow (3.1.1)
+    rake (13.4.2)
+    rbs (4.2.0)
+      logger
+      prism (>= 1.6.0)
+      tsort
+    rdoc (8.1.0)
+      erb
+      prism (>= 1.6.0)
+      rbs (>= 4.0.0)
+      tsort
+    readline (0.0.4)
+      reline
+    regexp_parser (2.13.1)
+    reline (0.7.0)
+      io-console (~> 0.5)
+    rubocop (1.91.0)
+      json (>= 2.3)
+      language_server-protocol (~> 3.17.0.2)
+      lint_roller (~> 1.1.0)
+      parallel (>= 1.10)
+      parser (>= 3.3.0.2)
+      rainbow (>= 2.2.2, < 4.0)
+      regexp_parser (>= 2.9.3, < 3.0)
+      rubocop-ast (>= 1.49.0, < 2.0)
+      ruby-progressbar (~> 1.7)
+      unicode-display_width (>= 2.4.0, < 4.0)
+    rubocop-ast (1.50.0)
+      parser (>= 3.3.7.2)
+      prism (~> 1.7)
+    rubocop-rake (0.7.1)
+      lint_roller (~> 1.1)
+      rubocop (>= 1.72.1)
+    ruby-progressbar (1.13.0)
+    sync (0.5.0)
+    term-ansicolor (1.11.3)
+      tins (~> 1)
+    tins (1.60.0)
+      bigdecimal
+      irb
+      mize (~> 0.6)
+      readline
+      sync
+    tsort (0.2.0)
+    unicode-display_width (3.3.0)
+      unicode-emoji (~> 4.3)
+    unicode-emoji (4.3.0)
+    uri (1.1.1)
+
+PLATFORMS
+  ruby
+  x86_64-linux
+
+DEPENDENCIES
+  faraday (~> 2.14)
+  faraday-follow_redirects (~> 0.5)
+  rake (~> 13.4)
+  rubocop (~> 1.91)
+  rubocop-rake (~> 0.7)
+  term-ansicolor (~> 1.11)
+
+CHECKSUMS
+  ast (2.4.3) sha256=954615157c1d6a382bc27d690d973195e79db7f55e9765ac7c481c60bdb4d383
+  bigdecimal (4.1.3) sha256=61ebe1e5e559bdc3cc6f2c0ee7f427321fc838f59611c294356eb04d6e21cf66
+  erb (6.0.7) sha256=c5ca6dc25b0ef974a44dc8f59fe847577122483b1968a38dec305c60bf91ee92
+  faraday (2.14.4) sha256=9bb4408c44621b0dbaaaa39e5dbfc4dbe58cc6751b6eb94d16ae9e1f2f2fab6e
+  faraday-follow_redirects (0.5.0) sha256=5cde93c894b30943a5d2b93c2fe9284216a6b756f7af406a1e55f211d97d10ad
+  faraday-net_http (3.4.4) sha256=0e78af151747ed1b00f33e25973b4bc220d7f16c00c39676817c8b12331eb588
+  io-console (0.9.4) sha256=a403304f32928ee85e56d457b4612ca43f2703b561a3258844992bd24085fbb1
+  irb (1.18.0) sha256=de9454a0703a54704b9811a5ef31a60c86949fbf4013fcf244fabc7c775248e3
+  json (3.0.2) sha256=8e6d7e7b11384c21230430cef90b71f14849a34a1f4452796670f7c981bd19df
+  language_server-protocol (3.17.0.6) sha256=5ef2c0c138f8267e1bc631d3328347d354f96724b0af22f2c79516120443b7f0
+  lint_roller (1.1.0) sha256=2c0c845b632a7d172cb849cc90c1bce937a28c5c8ccccb50dfd46a485003cc87
+  logger (1.7.0) sha256=196edec7cc44b66cfb40f9755ce11b392f21f7967696af15d274dde7edff0203
+  mize (0.6.1) sha256=4031558979ff5426fda24c75a149b4e4c0faf4cacf2fae8938f83866ab94b780
+  net-http (0.9.1) sha256=25ba0b67c63e89df626ed8fac771d0ad24ad151a858af2cc8e6a716ca4336996
+  parallel (2.3.0) sha256=f75a3e904101ce6a1ccb6b8dc800cbafd42166d83330192438dcf29395167a6f
+  parser (3.3.12.0) sha256=21a6d7f755d5a24dfbdc6e6b772e4e879a52e7631a88bc5a3a134606052c9828
+  pp (0.6.4) sha256=dfcb0fce700c41456265922884f9fe195d7fbb0674a3578e6c0f69588e82b570
+  prettyprint (0.2.0) sha256=2bc9e15581a94742064a3cc8b0fb9d45aae3d03a1baa6ef80922627a0766f193
+  prism (1.9.0) sha256=7b530c6a9f92c24300014919c9dcbc055bf4cdf51ec30aed099b06cd6674ef85
+  racc (1.8.1) sha256=4a7f6929691dbec8b5209a0b373bc2614882b55fc5d2e447a21aaa691303d62f
+  rainbow (3.1.1) sha256=039491aa3a89f42efa1d6dec2fc4e62ede96eb6acd95e52f1ad581182b79bc6a
+  rake (13.4.2) sha256=cb825b2bd5f1f8e91ca37bddb4b9aaf345551b4731da62949be002fa89283701
+  rbs (4.2.0) sha256=51f7b886dcc05bc09e10b901daa6a81829f6adc03101d6ca9ea4aac6103e0674
+  rdoc (8.1.0) sha256=befc37880a5cfd36dcb176c748b5fd5ee39dd3536a75e81824e4972ce230f60a
+  readline (0.0.4) sha256=6138eef17be2b98298b672c3ea63bf9cb5158d401324f26e1e84f235879c1d6a
+  regexp_parser (2.13.1) sha256=5aedb6b7c35688f51e86eef17a15374dfd287c83f4ca644b2c5f3ec50a33b44b
+  reline (0.7.0) sha256=5b012d8e55dbf9d450f12bde2cf7d15ff546ae80b3f8f3b30e570d431815583d
+  rubocop (1.91.0) sha256=9c82b7bf391c5d7e3798c5b9996e22a1fe3bd7468e351dfdeb96140c058296d0
+  rubocop-ast (1.50.0) sha256=b9ca88300da0803ee222ad20cdb30494c0a784eed06fdc35d254b06d662788db
+  rubocop-rake (0.7.1) sha256=3797f2b6810c3e9df7376c26d5f44f3475eda59eb1adc38e6f62ecf027cbae4d
+  ruby-progressbar (1.13.0) sha256=80fc9c47a9b640d6834e0dc7b3c94c9df37f08cb072b7761e4a71e22cff29b33
+  sync (0.5.0) sha256=668356cc07c59ac7ed9ecf34fec3929831f179c07adb1f3e1c3b7a1609a638fd
+  term-ansicolor (1.11.3) sha256=8c01ec3abd095eb94dca8aed5a127d36e594239eb525eb306259c9e930534603
+  tins (1.60.0) sha256=919f9b6e4cc3aa0d80fb37d43118c8fb093462a4482bbcf2728bde47d4a80791
+  tsort (0.2.0) sha256=9650a793f6859a43b6641671278f79cfead60ac714148aabe4e3f0060480089f
+  unicode-display_width (3.3.0) sha256=4b7aa66a4b11db50f6f7e98411215cd0dd10eaecb665d36eec5bcacb3fa0b613
+  unicode-emoji (4.3.0) sha256=11c02fa73290378c066bb0562cd4c87d8e1b706fbbe0059ca12746a4244de8ce
+  uri (1.1.1) sha256=379fa58d27ffb1387eaada68c749d1426738bd0f654d812fcc07e7568f5c57c6
+
+BUNDLED WITH
+  4.0.20
diff --git a/Rakefile b/Rakefile
index a5e0ebd..5adb525 100644
--- a/Rakefile
+++ b/Rakefile
@@ -7,9 +7,8 @@ require 'rake/clean'
 
 CLOBBER.include 'build'
 
-task default: 'source/main.elna'
-task default: 'build/gcc/elna' do |t|
-  sources, compiler  = t.prerequisites.partition { |f| f.end_with? '.elna' }
+task default: ['source/main.elna', 'build/gcc/elna'] do |t|
+  sources, compiler = t.prerequisites.partition { |f| f.end_with? '.elna' }
 
-  sh *compiler, '--parse', *sources
+  sh(*compiler, '--parse', *sources)
 end
diff --git a/rakelib/compiler.rake b/rakelib/compiler.rake
index f443407..4731e1d 100644
--- a/rakelib/compiler.rake
+++ b/rakelib/compiler.rake
@@ -11,7 +11,7 @@ CLEAN.include 'build/gcc'
 Rake.application.add_loader('d', Rake::MakefileLoader.new)
 FileList['build/gcc/**/*.d'].each { |file| import file }
 
-rule(/gcc\/.+\.o$/ => ->(file) {
+rule(%r{gcc/.+\.o$} => lambda { |file|
   source = Pathname.new('source') +
     Pathname.new(file).relative_path_from('build/gcc').sub_ext('.elna')
 
@@ -22,9 +22,8 @@ rule(/gcc\/.+\.o$/ => ->(file) {
   sh t.prerequisites.last, '-c', '-MD', '-MP', '-O0', '-g', '-I', 'source', '-o', t.name, t.source.to_s
 end
 
-file 'build/gcc/elna' => FileList['source/**/*.elna'].reject { |file|
-  file != file.downcase
-}.map { |file|
+sources = FileList['source/**/*.elna'].select { |file| file == file.downcase }
+file 'build/gcc/elna' => sources.map { |file|
   Pathname.new('build/gcc') +
     Pathname.new(file).relative_path_from('source').sub_ext('.o')
 } do |t|
diff --git a/rakelib/doc.rake b/rakelib/doc.rake
index 5f40107..bf92293 100644
--- a/rakelib/doc.rake
+++ b/rakelib/doc.rake
@@ -18,6 +18,7 @@ rule '.bbl' => '.bcf' do |t|
 end
 
 namespace :doc do
+  desc 'Compile LaTeX documentation'
   task tex: 'build/doc' do |t|
     sh 'pdflatex', '-output-directory', "../#{t.prerequisites.first}", 'report',
       chdir: 'doc'
diff --git a/rakelib/gcc.rake b/rakelib/gcc.rake
index 7ee9f5c..6dce877 100644
--- a/rakelib/gcc.rake
+++ b/rakelib/gcc.rake
@@ -5,8 +5,18 @@
 
 require 'fileutils'
 require 'uri'
-require 'net/http'
-require 'open3'
+require 'faraday'
+require 'faraday/follow_redirects'
+require 'English'
+require_relative 'support/ui'
+
+# Dependencies.
+GCC_VERSION = '16.2.0'
+GCC_HOST = 'build/host/gcc'
+GCC_HOST_INSTALL = Pathname.new 'build/host/install'
+GCC_TREE = Pathname.new "build/tools/gcc-#{GCC_VERSION}"
+GCC_PATCH =
+  "https://raw.githubusercontent.com/Homebrew/homebrew-core/refs/heads/main/Patches/gcc/gcc-#{GCC_VERSION}.diff".freeze
 
 # Use Homebrew GCC if available (it uses libstdc++, avoiding
 # macOS-specific libc++ incompatibilities in GCC's own sources).
@@ -34,59 +44,50 @@ end
 
 def gcc_verbose(gcc_binary)
   read, write = IO.pipe
-  sh({'LC_ALL' => 'C'}, gcc_binary, '--verbose', err: write)
+  sh({ 'LC_ALL' => 'C' }, gcc_binary, '--verbose', err: write)
   write.close
   output = read.read
   read.close
   output
 end
 
-def find_build_target(gcc_version)
-  if RUBY_PLATFORM =~ /darwin/
-    suffix = '-' + gcc_version.split('.').first
-    mac_os_sdk = '/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk'
-  else
-    suffix = ''
-  end
-  build_target = gcc_verbose(ENV.fetch 'CC', "gcc#{suffix}")
+def target_triple(cc_name)
+  gcc_verbose(cc_name)
     .lines
     .find { |line| line.start_with? 'Target: ' }
-    .split(' ')
+    .split
     .last
     .strip
+end
+
+def find_build_target(gcc_version)
+  is_darwin = RUBY_PLATFORM =~ /darwin/
+  suffix = is_darwin ? "-#{gcc_version.split('.').first}" : ''
+  mac_os_sdk = '/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk' if is_darwin
+  build_target = target_triple(ENV.fetch('CC', "gcc#{suffix}"))
 
   GCCConfiguration.new suffix, build_target, mac_os_sdk
 end
 
+def pipe_to_command(command, chdir:, &)
+  IO.popen(command, 'w', chdir:, &)
+  UI.fatal "Command #{command.join(' ')} failed" unless $CHILD_STATUS.success?
+end
+
+def stream_http(url, &)
+  conn = Faraday.new do |f|
+    f.response :follow_redirects
+    f.response :raise_error
+  end
+  conn.get(url) do |req|
+    req.options.on_data = ->(chunk, _, env) { yield chunk if (200..299).cover?(env.status) && !chunk.empty? }
+  end
+end
+
 def download_and_pipe(url, target, command)
   target.mkpath
-
-  Net::HTTP.start(url.host, url.port, use_ssl: url.scheme == 'https') do |http|
-    request = Net::HTTP::Get.new url.request_uri
-
-    http.request request do |response|
-      case response
-      when Net::HTTPRedirection
-        download_and_pipe URI.parse(response['location']), target, command
-      when Net::HTTPSuccess
-        Dir.chdir target.to_path do
-          Open3.popen2(*command) do |stdin, stdout, wait_thread|
-            Thread.new do
-              stdout.each { |line| puts line }
-            end
-
-            response.read_body do |chunk|
-              stdin.write chunk
-            end
-            stdin.close
-
-            wait_thread.value
-          end
-        end
-      else
-        response.error!
-      end
-    end
+  pipe_to_command(command, chdir: target.to_path) do |stdin|
+    stream_http(url) { |chunk| stdin.write chunk }
   end
 end
 
@@ -104,60 +105,69 @@ def convert_directive(line, directive, dg_name)
   end
 end
 
+def test_trailer_lines(category, extra_lines = [])
+  lines = []
+  lines << '(* { dg-do run } *)' if category == 'runnable'
+  lines.concat extra_lines
+  lines << '(* { dg-prune-output .* } *)'
+  case category
+  when 'compilable' then lines << '(* { dg-final { output-exists } } *)'
+  when 'fail_compilation' then lines << '(* { dg-final { output-exists-not } } *)'
+  end
+  lines
+end
+
 def convert_test(source, target, category, extra_lines = [])
   File.open(target, 'wb') do |output|
     File.foreach(source) do |line|
       line = convert_directive(line, '@Error', 'dg-error')
-      line = convert_directive(line, '@Flags', 'dg-additional-options')
-
-      output.puts line
+      output.puts convert_directive(line, '@Flags', 'dg-additional-options')
     end
 
-    # Runnable tests compile, link and execute.
-    output.puts '(* { dg-do run } *)' if category == 'runnable'
+    test_trailer_lines(category, extra_lines).each { |line| output.puts line }
+  end
+end
+
+def multi_module_extra_sources(test_target)
+  sources = test_target.glob('**/*.elna')
+    .map { |extra| %("#{extra.relative_path_from(test_target)}") }
+  "(* { dg-additional-sources #{sources * ' '} } *)"
+end
 
-    extra_lines.each { |line| output.puts line }
+def convert_multi_module_test(test_path, test_target, category)
+  main = test_path / 'sut.elna'
+  UI.fatal "Multi-module test directory \"#{test_path}\" must contain sut.elna." unless main.file?
 
-    # Suppress excess output so stray diagnostics do not fail the test.
-    output.puts '(* { dg-prune-output .* } *)'
+  test_target.mkdir
+  (test_path.children - [main]).each { |extra| cp_r extra, test_target }
+  extra_lines = ["(* { dg-additional-options \"-I#{test_target.expand_path}\" } *)"]
+  extra_lines << multi_module_extra_sources(test_target) if category == 'runnable'
 
-    case category
-    when 'compilable'
-      # Assert that an output file was produced.
-      output.puts '(* { dg-final { output-exists } } *)'
-    when 'fail_compilation'
-      # Assert that no output file was produced.
-      output.puts '(* { dg-final { output-exists-not } } *)'
-    end
-  end
+  convert_test main, test_target / 'sut.elna', category, extra_lines
 end
 
 namespace :gcc do
-  # Dependencies.
-  GCC_VERSION = "16.2.0"
-  HOST_GCC = 'build/host/gcc'
-  HOST_INSTALL = Pathname.new 'build/host/install'
-  GCC_TREE = Pathname.new "build/tools/gcc-#{GCC_VERSION}"
-  GCC_PATCH =
-    "https://raw.githubusercontent.com/Homebrew/homebrew-core/refs/heads/main/Patches/gcc/gcc-#{GCC_VERSION}.diff"
-
-  directory HOST_GCC
-  directory HOST_INSTALL.to_path
+  directory GCC_HOST
+  directory GCC_HOST_INSTALL.to_path
   directory 'build/tools'
 
   desc 'Download the bootstrap compiler and its prerequisites'
   task download: 'build/tools' do
+    UI.step "Downloading bootstrap compiler and prerequisites (GCC #{GCC_VERSION})..."
     url = URI.parse "https://gcc.gnu.org/pub/gcc/releases/gcc-#{GCC_VERSION}/gcc-#{GCC_VERSION}.tar.xz"
 
+    UI.debug "Downloading #{url}..."
     download_and_pipe url, GCC_TREE.dirname, ['tar', '-Jxv']
+    UI.debug "Downloading and applying patch #{GCC_PATCH}..."
     download_and_pipe URI.parse(GCC_PATCH), GCC_TREE, ['patch', '-p1']
 
     # GCC 16.1.0 registers 17 languages but CL_PARAMS is at bit 16,
     # which collides with the 17th language class (CL_Rust). Shift
     # every CL_* constant from bit 16 upward by one position.
-    File.open(GCC_TREE + 'gcc/opts.h', 'r+') do |opts_h|
-      content = opts_h.read.gsub(/\(1U << (\d+)\)/) do |m|
-        "(1U << #{$1.to_i + 1})"
+    UI.debug 'Patching gcc/opts.h to shift CL_* flags...'
+    File.open(GCC_TREE / 'gcc/opts.h', 'r+') do |opts_h|
+      content = opts_h.read.gsub(/\(1U << (\d+)\)/) do
+        "(1U << #{Regexp.last_match(1).to_i + 1})"
       end
       opts_h.seek 0, IO::SEEK_SET
       opts_h.write content
@@ -168,8 +178,9 @@ namespace :gcc do
 
   desc 'Link the frontend into the GCC source tree'
   task :link do
-    source_destination = GCC_TREE + 'gcc/elna'
-    test_destination = GCC_TREE + 'gcc/testsuite/elna.dg'
+    UI.step 'Linking Elna frontend into the GCC source tree...'
+    source_destination = GCC_TREE / 'gcc/elna'
+    test_destination = GCC_TREE / 'gcc/testsuite/elna.dg'
 
     rm_rf [source_destination, test_destination]
     mkdir_p [source_destination, test_destination]
@@ -180,16 +191,17 @@ namespace :gcc do
     FileList['gcc/dg.exp', 'README.md'].each do |file|
       link_frontend file, test_destination
     end
-    destination = GCC_TREE + 'gcc/testsuite/lib'
+    destination = GCC_TREE / 'gcc/testsuite/lib'
     FileList['gcc/testlib/*'].each do |file|
-      rm_f (destination + File.basename(file))
+      rm_f destination / File.basename(file)
       link_frontend file, destination
     end
   end
 
   desc 'Configure the bootstrap compiler'
-  task configure: [HOST_GCC, HOST_INSTALL.to_path] do |t|
+  task configure: [GCC_HOST, GCC_HOST_INSTALL.to_path] do |t|
     build_target = find_build_target GCC_VERSION
+    UI.step "Configuring bootstrap compiler for #{build_target.target}..."
     configure_options = [
       "--prefix=#{File.realpath t.prerequisites.last}",
       '--enable-languages=c,c++,jit,elna',
@@ -208,25 +220,28 @@ namespace :gcc do
     }
     env['CFLAGS'] = env['CXXFLAGS'] = '-O0 -g -fPIC -I/opt/homebrew/opt/flex/include'
 
-    configure = GCC_TREE.relative_path_from(HOST_GCC) + 'configure'
-    sh env, configure.to_path, *configure_options, chdir: HOST_GCC
+    configure = GCC_TREE.relative_path_from(GCC_HOST) / 'configure'
+    sh env, configure.to_path, *configure_options, chdir: GCC_HOST
   end
 
   desc 'Make and install the bootstrap compiler'
   task :make do
-    sh 'make', '-j', Etc.nprocessors.to_s, chdir: HOST_GCC
-    sh 'make', 'install', chdir: HOST_GCC
+    UI.step "Building bootstrap compiler (jobs: #{Etc.nprocessors})..."
+    sh 'make', '-j', Etc.nprocessors.to_s, chdir: GCC_HOST
+    sh 'make', 'install', chdir: GCC_HOST
   end
 
   desc 'Convert the testsuite into dejagnu format'
   task :convert do
-    destination = GCC_TREE + 'gcc/testsuite/elna.dg'
+    UI.step 'Converting testsuite to DejaGnu format...'
+    destination = GCC_TREE / 'gcc/testsuite/elna.dg'
     destination.mkpath
     source = Pathname.new 'testsuite'
 
     # Regenerate the category directories from scratch: this removes
     # converted tests whose sources are gone and adds new ones.
     %w[compilable fail_compilation runnable].each do |category|
+      UI.debug "Converting #{category} tests..."
       category_destination = destination + category
       category_source = source + category
 
@@ -235,32 +250,8 @@ namespace :gcc do
 
       category_source.each_child do |test_path|
         test_target = category_destination + test_path.basename
-
-        # Multi-module tests: directories containing a sut.elna (system under
-        # test) and any helper files, compiled and linked together.
         if test_path.directory?
-          main = test_path + 'sut.elna'
-          raise %(multi-module test directory \"#{test_path}\" must contain sut.elna) unless main
-
-          test_target.mkdir
-          modules = test_path.children - [main]
-
-          modules.each do |extra|
-            cp_r extra, test_target
-          end
-          extra_lines = ["(* { dg-additional-options \"-I#{test_target.expand_path}\" } *)"]
-
-          # Only 'runnable' tests link the helper modules into an executable,
-          # so only they need the helper sources compiled as separate
-          # translation units via dg-additional-sources. Elna resolves imports
-          # on its own, so passing it as an additional source there would add a
-          # second positional.
-          if category == 'runnable'
-            extra_sources = test_target.glob("**/*.elna")
-              .map { |extra| %("#{extra.relative_path_from test_target}") }
-            extra_lines << "(* { dg-additional-sources #{extra_sources * ' '} } *)"
-          end
-          convert_test main, (test_target + 'sut.elna'), category, extra_lines
+          convert_multi_module_test test_path, test_target, category
         else
           convert_test test_path, test_target, category
         end
@@ -270,25 +261,27 @@ namespace :gcc do
 
   desc 'Run tests'
   task check: 'gcc:convert' do
-    log_file = Pathname.new(HOST_GCC) + 'gcc/testsuite/elna/elna.log'
-
-    sh 'make', 'check-elna', chdir: File.join(HOST_GCC, 'gcc')
+    UI.step 'Running DejaGnu testsuite...'
+    log_file = Pathname.new(GCC_HOST) / 'gcc/testsuite/elna/elna.log'
 
-    fail "\nSee #{log_file}." if log_file.file? and log_file.read =~ /^(FAIL|XPASS|UNRESOLVED|ERROR):/
+    sh 'make', 'check-elna', chdir: File.join(GCC_HOST, 'gcc')
+    UI.fatal "See #{log_file}." if log_file.file? && log_file.read =~ /^(FAIL|XPASS|UNRESOLVED|ERROR):/
   end
 
   desc 'Run clang-tidy'
   task :tidy do
     compile_db = Pathname.new 'compile_commands.json'
 
-    raise "#{compile_db} is missing. Run: bear -- rake gcc:make" unless compile_db.exist?
+    UI.fatal "#{compile_db} is missing.", hint: 'Run: bear -- rake gcc:make' unless compile_db.exist?
+
     sources = FileList['boot/*.cc', 'gcc/gcc/*.cc', 'include/elna/**/*.h']
       .reject do |file|
         ['/elna1.', '/elna-spec.'].any? { |pattern| file.include? pattern }
       end
+    UI.step "Running clang-tidy on #{sources.size} files..."
     build_target = find_build_target GCC_VERSION
     includes = ['.', build_target.target].collect do |inc|
-      HOST_INSTALL + 'include/c++' + GCC_VERSION + inc
+      GCC_HOST_INSTALL / 'include/c++' / GCC_VERSION / inc
     end
 
     sh 'clang-tidy', '-p', compile_db.to_path, '--extra-arg=-w', '--warnings-as-errors=*',
@@ -298,7 +291,7 @@ namespace :gcc do
 
   desc 'Build documentation'
   task :doc do
-    sh 'make', 'html', chdir: File.join(HOST_GCC, 'gcc')
+    sh 'make', 'html', chdir: File.join(GCC_HOST, 'gcc')
   end
 
   desc 'Run GCC linters and tests'
diff --git a/rakelib/ruby.rake b/rakelib/ruby.rake
new file mode 100644
index 0000000..c3db30a
--- /dev/null
+++ b/rakelib/ruby.rake
@@ -0,0 +1,11 @@
+# This Source Code Form is subject to the terms of the Mozilla Public License,
+# v. 2.0. If a copy of the MPL was not distributed with this file, You can
+# obtain one at https://mozilla.org/MPL/2.0/.
+# frozen_string_literal: true
+
+require 'rubocop/rake_task'
+
+namespace :ruby do
+  desc 'Run RuboCop'
+  RuboCop::RakeTask.new :lint
+end
diff --git a/rakelib/support/ui.rb b/rakelib/support/ui.rb
new file mode 100644
index 0000000..3120721
--- /dev/null
+++ b/rakelib/support/ui.rb
@@ -0,0 +1,25 @@
+# This Source Code Form is subject to the terms of the Mozilla Public License,
+# v. 2.0. If a copy of the MPL was not distributed with this file, You can
+# obtain one at https://mozilla.org/MPL/2.0/.
+# frozen_string_literal: true
+
+require 'term/ansicolor'
+
+# Terminal UI helpers for build milestones, debug logging, and operational errors.
+module UI
+  extend Term::ANSIColor
+
+  def self.step(message)
+    puts green(message)
+  end
+
+  def self.debug(message)
+    puts "#{dark(' ->')} #{dark(message)}" if Rake.verbose
+  end
+
+  def self.fatal(message, hint: nil)
+    output = red(message)
+    output += "\n#{bold(cyan('Hint:'))} #{hint}" if hint
+    abort output
+  end
+end
diff --git a/rakelib/treesitter.rake b/rakelib/treesitter.rake
index 7e48865..ca0c8d0 100644
--- a/rakelib/treesitter.rake
+++ b/rakelib/treesitter.rake
@@ -18,8 +18,8 @@ namespace :ts do
     cp_r TREE_SITTER_TREE, TREE_SITTER_BUILD unless TREE_SITTER_BUILD.directory?
 
     sh 'tree-sitter', 'generate',
-      '--output', (TREE_SITTER_BUILD + 'src').to_path,
-      (TREE_SITTER_TREE + 'grammar.js').to_path
+      '--output', (TREE_SITTER_BUILD / 'src').to_path,
+      (TREE_SITTER_TREE / 'grammar.js').to_path
 
     build_test = TREE_SITTER_BUILD / 'test'
     build_corpus = build_test / 'corpus'
@@ -44,7 +44,7 @@ namespace :ts do
 
       File.open target, 'w' do |output|
         output.write "==================\n"
-        output.write(File.basename(test, '.elna') + "\n")
+        output.write "#{File.basename(test, '.elna')}\n"
         output.write "==================\n\n"
         output.write File.read(test)
         output.write "\n---\n\n"
@@ -61,5 +61,4 @@ namespace :ts do
 end
 
 desc 'Build a tree-sitter parser'
-task ts: 'ts:generate'
-task ts: "#{TREE_SITTER_BUILD}/parser.so"
+task ts: ['ts:generate', "#{TREE_SITTER_BUILD}/parser.so"]