Cached compiled erb templates in procs

lib/tilt.rb

@@ -187,6 +187,11 @@ def template_source
   # ERB template implementation. See:
   # http://www.ruby-doc.org/stdlib/libdoc/erb/rdoc/classes/ERB.html
   class ERBTemplate < Template
+    def initialize(*args)
+      super
+      @template_procs = {}
+    end
+
     def compile!
       require_template_library 'erb' unless defined?(::ERB)
       @engine = ::ERB.new(data, options[:safe], options[:trim], '@_out_buf')
@@ -197,14 +202,11 @@ def template_source
     end
 
     def evaluate(scope, locals, &block)
-      source, offset = local_assignment_code(locals)
-      source = [source, template_source].join("\n")
-
       original_out_buf =
         scope.instance_variables.any? { |var| var.to_sym == :@_out_buf } &&
         scope.instance_variable_get(:@_out_buf)
 
-      scope.instance_eval source, eval_file, line - offset
+      scope.instance_eval(&template_proc(locals))
 
       output = scope.instance_variable_get(:@_out_buf)
       scope.instance_variable_set(:@_out_buf, original_out_buf)
@@ -213,6 +215,13 @@ def evaluate(scope, locals, &block)
     end
 
   private
+    def template_proc(locals)
+      @template_procs[locals] ||= begin
+        source, offset = local_assignment_code(locals)
+        source = [source, template_source].join("\n")
+        instance_eval("proc { #{source} }", eval_file, line - offset)
+      end
+    end
 
     # ERB generates a line to specify the character coding of the generated
     # source in 1.9. Account for this in the line offset.