Mercurial > hg > mhoward > dotfiles / changeset

new file mode 100644
--- /dev/null
+++ b/.lib/ruby/data_embed.rb
@@ -0,0 +1,69 @@
+module DataEmbed
+  module_function
+
+  # Returns a hash of filename => content read from the DATA section of a given
+  # source, or the caller.  Does not cache for you.  If given a handle, it is
+  # read; a string, used as a file path to read; a module or class, its file is
+  # guessed using +const_source_location+.
+  #
+  # Note: This isn't careful with encoding.  A battle-tested version of this
+  # that should be okay with encodings can be found in Sinatra.
+  #
+  # @example Read my own data section
+  #   files = DataEmbed.data_section(__FILE__)
+  #
+  # @example A specific module
+  #   files = DataEmbed.data_section(Some::Class)
+  #
+  # @example The DATA global (only opened for $0 unlike perl)
+  #   files = DataEmbed.data_section(DATA)
+  #
+  # @param source [Module, String, #read]
+  # @return [{String => String}]
+  def data_section(source)
+    data =
+      case source
+      when Module
+        File.read(Object.const_source_location(source.name)[0])
+      when String
+        File.read(source)
+      else
+        source.read
+      end
+
+    data
+      .split(/^__END__$/, 2)
+      .last
+      .split(/^@@\s*(.+?)\s*\r?\n/m)
+      .tap { _1.shift if _1.length.odd? }
+      .each_slice(2)
+      .to_h
+      .transform_values { _1.gsub(/\n+\z/, "\n") }
+  end
+
+  # Process the given tmpl using ERB, with % trim enabled.  Either a binding or
+  # a hash may be given.  Only locals are available to the template if a hash
+  # is used.
+  #
+  # @param tmpl [String]
+  # @param vars [Binding, Hash]
+  # @return [String]
+  def process_template(tmpl, vars)
+    require "erb"
+
+    ERB
+      .new(tmpl, trim_mode: "%")
+      .public_send(vars.is_a?(Binding) ? :result : :result_with_hash, vars)
+  end
+
+  # Process templates in both keys and values of the given hash
+  # 
+  # @param data [{String => String}]
+  # @param vars [Binding, Hash]
+  # @return [{String => String}]
+  def process_templates(data, vars)
+    data
+      .transform_keys { process_template(_1, vars) }
+      .transform_values! { process_template(_1, vars) }
+  end
+end