Use namespaces according to Rake conventions

Change the Rake task to one that uses namespaces as follows (previous task
names can also be used for compatibility).

| Previous Task  |    New Task    |
|----------------|----------------|
| api_doc        | doc:api        |
| capi_doc       | doc:capi       |
| clean_doc      | doc:clean      |
| clean_api_doc  | doc:clean:api  |
| clean_capi_doc | doc:clean:capi |
| view_api       | doc:view:api   |
| view_capi      | doc:view:capi  |
| gitlab_config  | gitlab:config  |
| gitlab_dockers | gitlab:dockers |

tasks/doc.rake

 desc 'generate document'
-task :doc => [:api_doc, :capi_doc] do
+task :doc => %w[doc:api doc:capi]
 
-end
-
-desc 'generate yard docs'
-task :api_doc do
+namespace :doc do
+  desc 'generate yard docs'
+  task :api do
     begin
       sh "mrbdoc"
     rescue
       puts "ERROR: To generate yard documentation, you should install yard-mruby gem."
       puts "  $ gem install yard-mruby yard-coderay"
     end
-end
+  end
 
-desc 'generate doxygen docs'
-task :capi_doc do
+  desc 'generate doxygen docs'
+  task :capi do
     begin
       sh "doxygen Doxyfile"
     rescue
       puts "ERROR: To generate C API documents, you need Doxygen."
       puts "  $ sudo apt-get install doxygen"
     end
-end
+  end
+
+  desc 'clean all built docs'
+  task :clean => %w[clean:api clean:capi]
 
-desc 'clean all built docs'
-task :clean_api_doc do
+  namespace :clean do
+    desc 'clean yard docs'
+    task :api do
       rm_rf 'doc/api'
-end
+    end
 
-desc 'clean all built docs'
-task :clean_capi_doc do
+    desc 'clean doxygen docs'
+    task :capi do
       rm_rf 'doc/capi'
-end
-
-desc 'clean all built docs'
-task :clean_doc => [:clean_api_doc, :clean_capi_doc] do
-end
+    end
+  end
 
-desc 'clean all built docs'
-task :view_api => [:api_doc] do
+  namespace :view do
+    desc 'open yard docs'
+    task :api do
       sh 'xdg-open doc/api/index.html'
-end
+    end
 
-desc 'clean all built docs'
-task :view_capi => [:capi_doc] do
+    desc 'open doxygen docs'
+    task :capi do
       sh 'xdg-open doc/capi/html/index.html'
+    end
+  end
 end
+
+# deprecated
+task "api_doc" => "doc:api"
+task "capi_doc" => "doc:capi"
+task "clean_doc" => "doc:clean"
+task "clean_api_doc" => "doc:clean:api"
+task "clean_capi_doc" => "doc:clean:capi"
+task "view_api" => "doc:view:api"
+task "view_capi" => "doc:view:capi"

tasks/gitlab.rake

@@ -25,8 +25,9 @@ def run_cmd(cmd)
   raise 'error' unless system cmd
 end
 
-desc 'recreate docker images for GitLab builds'
-task :gitlab_dockers do
+namespace :gitlab do
+  desc 'recreate docker images for GitLab builds'
+  task :dockers do
     CI_COMPILERS.each do |compiler|
       tag = ci_image_tag(compiler)
       filename = "Dockerfile.#{tag}"
@@ -54,10 +55,10 @@ task :gitlab_dockers do
       run_cmd cmd2
       File.delete(filename)
     end
-end
+  end
 
-desc 'create build configurations and update .gitlab-ci.yml'
-task :gitlab_config do
+  desc 'create build configurations and update .gitlab-ci.yml'
+  task :config do
     require 'yaml'
 
     configs = []
@@ -112,4 +113,9 @@ task :gitlab_config do
       end
     end
     File.open(path, 'w') { |f| YAML.dump(data, f) }
+  end
 end
+
+# deprecated
+task "gitlab_config" => "gitlab:config"
+task "gitlab_dockers" => "gitlab:dockers"