Improve eval, remove globals

exe/repubmark

@@ -10,12 +10,12 @@ require 'repubmark'
 
 FORMATS = %w[word_count html gemtext].freeze
 
-$format = String(ARGV[0]).freeze
-raise "Invalid format: #{$format.inspect}" unless FORMATS.include? $format
+format = String(ARGV[0]).freeze
+raise "Invalid format: #{format.inspect}" unless FORMATS.include? format
 
-$template = $stdin.read.freeze
+template = $stdin.read.freeze
 
-$config = Repubmark::Config.new(
+config = Repubmark::Config.new(
   base_url: 'https://causa-arcana.com',
   css_class_annotation: 'nice-annotation',
   css_class_blockquote_figure: 'nice-blockquote',
@@ -29,18 +29,17 @@ $config = Repubmark::Config.new(
   relative_urls: false,
 )
 
-$article = Repubmark::Elems::Article.new $config
-$article.tap do |article| # rubocop:disable Lint/UnusedBlockArgument
-  eval $template # rubocop:disable Security/Eval
-end
+$article = Repubmark::Elems::Article.new config
 
-case $format
-when 'word_count'
-  puts $article.word_count
-when 'html'
-  puts $article.to_html.strip
-when 'gemtext'
-  puts $article.to_gemtext.strip
-else
-  raise 'Unknown blog format'
-end
+context = BasicObject.new
+def context.article = $article
+context.instance_eval template, __FILE__, __LINE__
+
+output =
+  case format
+  when 'word_count' then $article.word_count
+  when 'html'       then $article.to_html
+  when 'gemtext'    then $article.to_gemtext
+  end.to_s.strip
+
+puts output unless output.empty?