feat: optimize template parse (#460)

api/core/prompt/prompt_template.py

@@ -1,10 +1,33 @@
 import re
 from typing import Any
 
+from jinja2 import Environment, meta
 from langchain import PromptTemplate
 from langchain.formatting import StrictFormatter
 
 
+class JinjaPromptTemplate(PromptTemplate):
+    template_format: str = "jinja2"
+    """The format of the prompt template. Options are: 'f-string', 'jinja2'."""
+
+    @classmethod
+    def from_template(cls, template: str, **kwargs: Any) -> PromptTemplate:
+        """Load a prompt template from a template."""
+        env = Environment()
+        ast = env.parse(template)
+        input_variables = meta.find_undeclared_variables(ast)
+
+        if "partial_variables" in kwargs:
+            partial_variables = kwargs["partial_variables"]
+            input_variables = {
+                var for var in input_variables if var not in partial_variables
+            }
+
+        return cls(
+            input_variables=list(sorted(input_variables)), template=template, **kwargs
+        )
+
+
 class OutLinePromptTemplate(PromptTemplate):
     @classmethod
     def from_template(cls, template: str, **kwargs: Any) -> PromptTemplate:
@@ -16,6 +39,24 @@ class OutLinePromptTemplate(PromptTemplate):
             input_variables=list(sorted(input_variables)), template=template, **kwargs
         )
 
+    def format(self, **kwargs: Any) -> str:
+        """Format the prompt with the inputs.
+
+        Args:
+            kwargs: Any arguments to be passed to the prompt template.
+
+        Returns:
+            A formatted string.
+
+        Example:
+
+        .. code-block:: python
+
+            prompt.format(variable1="foo")
+        """
+        kwargs = self._merge_partial_and_user_variables(**kwargs)
+        return OneLineFormatter().format(self.template, **kwargs)
+
 
 class OneLineFormatter(StrictFormatter):
     def parse(self, format_string):