Add support for using variables inside bot message definitions.

CHANGELOG.md

@@ -16,6 +16,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Changed the naming of the internal events to align to the upcoming UMIM spec (Unified Multimodal Interaction Management).
 comments.)
+- Add support for [using variables inside bot message definitions](./docs/user_guide/colang-language-syntax-guide.md#bot-messages-with-variables).
 
 ### Fixed
 

docs/user_guide/colang-language-syntax-guide.md

@@ -61,6 +61,24 @@ define bot ask welfare
 
 If more than one utterance is specified per bot message, the meaning is that one of them should be chosen randomly.
 
+##### Bot Messages with Variables
+
+The utterance definition can also include reference to variables (see the [Variables](#variables) section below).
+
+```colang
+define bot express greeting
+ "Hello there, $name!"
+```
+
+Alternatively, you can also use the Jinja syntax:
+
+```colang
+define bot express greeting
+ "Hello there, {{ name }}!"
+```
+
+**NOTE**: for more advanced use cases you can also use other Jinja features like `{% if ... %} ... {% endif %}`.
+
 #### Flows
 
 Flows represent how you want the conversation to unfold. It includes sequences of user messages, bot messages and potentially other events.

nemoguardrails/actions/llm/generation.py

@@ -23,6 +23,7 @@
 from functools import lru_cache
 from typing import List, Optional
 
+from jinja2 import Environment, meta
 from langchain.llms import BaseLLM
 
 from nemoguardrails.actions.actions import ActionResult, action
@@ -88,6 +89,9 @@ def __init__(
 
  self.llm_task_manager = llm_task_manager
 
+ # We also initialize the environment for rendering bot messages
+ self.env = Environment()
+
  def _init_user_message_index(self):
  """Initializes the index of user messages."""
 
@@ -409,6 +413,41 @@ async def generate_next_step(
 
  return ActionResult(return_value=None)
 
+ def _render_string(
+ self,
+ template_str: str,
+ context: Optional[dict] = None,
+ ) -> str:
+ """Render a string using the provided context information.
+
+ Args:
+ template_str: The string template to render.
+ context: The context for rendering.
+
+ Returns:
+ The rendered string.
+ """
+ # First, if we have any direct usage of variables in the string,
+ # we replace with correct Jinja syntax.
+ for param in re.findall(r"\$([^ \"'!?\-,;</]*(?:\w|]))", template_str):
+ template_str = template_str.replace(f"${param}", "{{" + param + "}}")
+
+ template = self.env.from_string(template_str)
+
+ # First, we extract all the variables from the template.
+ variables = meta.find_undeclared_variables(self.env.parse(template_str))
+
+ # This is the context that will be passed to the template when rendering.
+ render_context = {}
+
+ # Copy the context variables to the render context.
+ if context:
+ for variable in variables:
+ if variable in context:
+ render_context[variable] = context[variable]
+
+ return template.render(render_context)
+
  @action(is_system_action=True)
  async def generate_bot_message(
  self, events: List[dict], context: dict, llm: Optional[BaseLLM] = None
@@ -435,6 +474,9 @@ async def generate_bot_message(
 
  log.info("Found existing bot message: " + bot_utterance)
 
+ # We also need to render
+ bot_utterance = self._render_string(bot_utterance, context)
+
  # Check if the output is supposed to be the content of a context variable
  elif bot_intent[0] == "$" and bot_intent[1:] in context:
  bot_utterance = context[bot_intent[1:]]

tests/test_bot_message_rendering.py

@@ -16,21 +16,20 @@
 from nemoguardrails import RailsConfig
 from tests.utils import TestChat
 
-config = RailsConfig.from_content(
- """
- define user express greeting
- "hello"
 
- define flow
- user ask time
- $now = "12pm"
- bot $now
- """
-)
+def test_1():
+ config = RailsConfig.from_content(
+ """
+ define user express greeting
+ "hello"
 
+ define flow
+ user ask time
+ $now = "12pm"
+ bot $now
+ """
+ )
 
-def test_1():
- """Test that branching with `when` works correctly."""
  chat = TestChat(
  config,
  llm_completions=[
@@ -40,3 +39,35 @@ def test_1():
 
  chat >> "What is the time?!"
  chat << "12pm"
+
+
+def test_2():
+ config = RailsConfig.from_content(
+ """
+ define user express greeting
+ "hello"
+
+ define bot express greeting
+ "Hello, {{ name }}!"
+
+ define bot express greeting again
+ "Hello, $name!"
+
+
+ define flow
+ user express greeting
+ $name = "John"
+ bot express greeting
+ bot express greeting again
+ """
+ )
+
+ chat = TestChat(
+ config,
+ llm_completions=[
+ " express greeting",
+ ],
+ )
+
+ chat >> "Hi!"
+ chat << "Hello, John!\nHello, John!"