From 570e07fe570a8e813e3024cfbfb48a72d33182ea Mon Sep 17 00:00:00 2001
From: "jingyuan.zhao" <jingyuan.zhao@aktsk.jp>
Date: Tue, 27 Jan 2026 11:47:00 +0900
Subject: [PATCH 1/3] Define method using class_eval instead of define_method.

---
 lib/simple_json/simple_json_renderer.rb |  8 ++-----
 lib/simple_json/simple_json_template.rb | 30 +++++++++++++++++++++----
 2 files changed, 28 insertions(+), 10 deletions(-)

diff --git a/lib/simple_json/simple_json_renderer.rb b/lib/simple_json/simple_json_renderer.rb
index 1b098d1..9f1c35c 100644
--- a/lib/simple_json/simple_json_renderer.rb
+++ b/lib/simple_json/simple_json_renderer.rb
@@ -39,9 +39,7 @@ def load_template_from_file(template_path)
         SimpleJson.template_paths.each do |path|
           file_path = Rails.root.join("#{path}/#{template_path}.simple_json.rb").to_path
 
-          if File.exist?(file_path)
-            return define_template_method(template_path, file_path)
-          end
+          return define_template_method(template_path, file_path) if File.exist?(file_path)
         end
 
         nil
@@ -52,9 +50,7 @@ def define_template_method(template_path, file_path)
         @template_num += 1
         method_name = :"template_#{@template_num}"
         render_methods[template_path] = method_name
-        define_method(method_name, &SimpleJsonTemplate.new(file_path).lambda)
-
-        return method_name
+        SimpleJsonTemplate.new(file_path).define_to_class(self, method_name)
       end
 
       def render_methods
diff --git a/lib/simple_json/simple_json_template.rb b/lib/simple_json/simple_json_template.rb
index e64a9e5..4d4c3ed 100644
--- a/lib/simple_json/simple_json_template.rb
+++ b/lib/simple_json/simple_json_template.rb
@@ -7,20 +7,42 @@ def initialize(path)
       @source = File.read(path)
     end
 
-    def lambda
-      @lambda ||= eval(code, TOPLEVEL_BINDING, @path) # rubocop:disable Security/Eval
+    def define_to_class(klass, method_name)
+      method_string = to_method_string(method_name)
+      klass.class_eval(method_string, @path)
+
+      method_name
     end
 
+    private
+
     def code
       @code ||= lambda_stringify(@source)
     end
 
-    private
-
     def lambda_stringify(source)
       return source if source.match?(/^(?:\s*(?:#.*?)?\n)*\s*->/)
 
       "-> { #{source} }"
     end
+
+    def method_string_from_lambda(source, method_name)
+      replaced = source.sub(/\A(?<prefix>(?:[ \t]*(?:#.*?)?\n)*)(?<indent>[ \t]*)->\s*(?<args>\([^)]*\))?[ \t]*\{?[ \t]*(?<rest>[^\n]*)/) do
+        header = "#{Regexp.last_match(:prefix)}#{Regexp.last_match(:indent)}def #{method_name}#{Regexp.last_match(:args)}"
+        rest = Regexp.last_match(:rest)
+        rest.strip.empty? ? header : "#{header}; #{rest.lstrip}"
+      end
+      return unless replaced != source
+
+      brace_index = replaced.rindex('}')
+      return replaced unless brace_index
+
+      replaced[brace_index] = 'end'
+      replaced
+    end
+
+    def to_method_string(method_name)
+      method_string_from_lambda(code, method_name)
+    end
   end
 end

From e2520c1292201b630494dd41f81d3ad998be9f47 Mon Sep 17 00:00:00 2001
From: "jingyuan.zhao" <jingyuan.zhao@aktsk.jp>
Date: Tue, 27 Jan 2026 21:00:59 +0900
Subject: [PATCH 2/3] Update README.md

---
 README.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/README.md b/README.md
index c3c0a53..ec5a6dc 100644
--- a/README.md
+++ b/README.md
@@ -53,7 +53,7 @@ This project is built on work of [jb](https://github.com/amatsuda/jb).
 
 ## Template Syntax
 
-SimpleJson templates are simply lambda objects that return data(Hashes or Arrays) for json.
+SimpleJson templates should be written in Ruby lambda format. The template code is converted into a method and then invoked to produce data (Hashes or Arrays) for JSON.
 
 ```ruby
 -> {

From c78fd3614adfe0b9975c2a23d7c6ce67a7c29bbc Mon Sep 17 00:00:00 2001
From: "jingyuan.zhao" <jingyuan.zhao@aktsk.jp>
Date: Wed, 28 Jan 2026 12:44:57 +0900
Subject: [PATCH 3/3] Reuse methods when template cache disabled

---
 lib/simple_json/simple_json_renderer.rb | 19 ++++++++++++++-----
 lib/simple_json/simple_json_template.rb |  4 ++--
 2 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/lib/simple_json/simple_json_renderer.rb b/lib/simple_json/simple_json_renderer.rb
index 9f1c35c..5961765 100644
--- a/lib/simple_json/simple_json_renderer.rb
+++ b/lib/simple_json/simple_json_renderer.rb
@@ -46,17 +46,26 @@ def load_template_from_file(template_path)
       end
 
       def define_template_method(template_path, file_path)
-        @template_num ||= 0
-        @template_num += 1
-        method_name = :"template_#{@template_num}"
-        render_methods[template_path] = method_name
-        SimpleJsonTemplate.new(file_path).define_to_class(self, method_name)
+        template = SimpleJsonTemplate.new(file_path)
+        code_hash = template.code.hash
+
+        render_methods[template_path] = render_methods_cache.fetch(code_hash) do
+          @template_num ||= 0
+          @template_num += 1
+          method_name = :"template_#{@template_num}"
+          template.define_to_class(self, method_name)
+          render_methods_cache[code_hash] = method_name
+        end
       end
 
       def render_methods
         @render_methods ||= {}
       end
 
+      def render_methods_cache
+        @render_methods_cache ||= {}
+      end
+
       def clear_renderers
         @render_methods = {}
         @templates_loaded = false
diff --git a/lib/simple_json/simple_json_template.rb b/lib/simple_json/simple_json_template.rb
index 4d4c3ed..84befc1 100644
--- a/lib/simple_json/simple_json_template.rb
+++ b/lib/simple_json/simple_json_template.rb
@@ -14,12 +14,12 @@ def define_to_class(klass, method_name)
       method_name
     end
 
-    private
-
     def code
       @code ||= lambda_stringify(@source)
     end
 
+    private
+
     def lambda_stringify(source)
       return source if source.match?(/^(?:\s*(?:#.*?)?\n)*\s*->/)