use liquid templates

Gemfile.lock

@@ -1,8 +1,9 @@
 PATH
   remote: .
   specs:
-    llm_eval_ruby (0.2.0)
+    llm_eval_ruby (0.2.1)
       httparty (~> 0.22.0)
+      liquid (~> 5.5.0)
 
 GEM
   remote: https://rubygems.org/
@@ -17,6 +18,7 @@ GEM
       multi_xml (>= 0.5.2)
     json (2.7.5)
     language_server-protocol (3.17.0.3)
+    liquid (5.5.1)
     mini_mime (1.1.5)
     multi_xml (0.7.1)
       bigdecimal (~> 3.1)

lib/llm_eval_ruby/prompt_adapters/base.rb

@@ -14,7 +14,8 @@ def fetch_prompt(name:, version: nil)
         end
 
         def compile(prompt:, variables:)
-          raise NotImplementedError
+          compiled = render_template(prompt.content, variables)
+          LlmEvalRuby::PromptTypes::Compiled.new(adapter: self, role: prompt.role, content: compiled)
         end
 
         private
@@ -39,6 +40,11 @@ def wrap_response(response)
             end
           end
         end
+
+        def render_template(template, variables)
+          template = Liquid::Template.parse(template)
+          template.render(variables.stringify_keys)
+        end
       end
     end
   end

lib/llm_eval_ruby/prompt_adapters/langfuse.rb

@@ -12,21 +12,11 @@ def fetch_prompt(name:, version: nil)
           handle_response(response)
         end
 
-        def compile(prompt:, variables:)
-          compiled = format(convert_prompt(prompt.content), variables)
-          LlmEvalRuby::PromptTypes::Compiled.new(adapter: self, role: prompt.role, content: compiled)
-        end
-
         private
 
         def client
           @client ||= ApiClients::Langfuse.new(**LlmEvalRuby.config.langfuse_options)
         end
-
-        # convert {{variable}} to %<variable>s
-        def convert_prompt(prompt)
-          prompt.gsub(/\{\{([^}]+)\}\}/, '%<\1>s')
-        end
       end
     end
   end

lib/llm_eval_ruby/prompt_adapters/local.rb

@@ -1,5 +1,6 @@
 # frozen_string_literal: true
 
+require "liquid"
 require_relative "base"
 
 module LlmEvalRuby
@@ -19,18 +20,6 @@ def fetch_prompt(name:, version: nil) # rubocop:disable Lint/UnusedMethodArgumen
 
           handle_response(system_prompts + user_prompt)
         end
-
-        def compile(prompt:, variables:)
-          compiled = format(convert_prompt(prompt.content), variables)
-          LlmEvalRuby::PromptTypes::Compiled.new(adapter: self, role: prompt.role, content: compiled)
-        end
-
-        private
-
-        # convert {{variable}} to %<variable>s
-        def convert_prompt(prompt)
-          prompt.gsub(/\{\{([^}]+)\}\}/, '%<\1>s')
-        end
       end
     end
   end

lib/llm_eval_ruby/version.rb

@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 module LlmEvalRuby
-  VERSION = "0.2.0"
+  VERSION = "0.2.1"
 end

llm_eval_ruby.gemspec

@@ -36,6 +36,7 @@ Gem::Specification.new do |spec|
   # Uncomment to register a new dependency of your gem
   # spec.add_dependency "example-gem", "~> 1.0"
   spec.add_dependency "httparty", "~> 0.22.0"
+  spec.add_dependency "liquid", "~> 5.5.0"
 
   # For more information and examples about making a new gem, check out our
   # guide at: https://bundler.io/guides/creating_gem.html

spec/llm_eval_ruby_spec.rb

@@ -2,6 +2,6 @@
 
 RSpec.describe LlmEvalRuby do
   it "has a version number" do
-    expect(LlmEvalRuby::VERSION).to be("0.2.0")
+    expect(LlmEvalRuby::VERSION).to be("0.2.1")
   end
 end