Harrison/jinja formatter (#385)

Co-authored-by: Benjamin <BenderV@users.noreply.github.com>

docs/examples/prompts/prompt_management.ipynb

@@ -71,7 +71,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 1,
+   "execution_count": 11,
    "id": "094229f4",
    "metadata": {},
    "outputs": [],
@@ -151,6 +151,59 @@
     "multiple_input_prompt.format(adjective=\"funny\", content=\"chickens\")"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "id": "b2dd6154",
+   "metadata": {},
+   "source": [
+    "## Alternative formats\n",
+    "\n",
+    "This section shows how to use alternative formats besides \"f-string\" to format prompts."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 13,
+   "id": "53b41b6a",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "# Jinja2\n",
+    "template = \"\"\"\n",
+    "{% for item in items %}\n",
+    "Question: {{ item.question }}\n",
+    "Answer: {{ item.answer }}\n",
+    "{% endfor %}\n",
+    "\"\"\"\n",
+    "items=[{\"question\": \"foo\", \"answer\": \"bar\"},{\"question\": \"1\", \"answer\": \"2\"}]\n",
+    "jinja2_prompt = PromptTemplate(\n",
+    "    input_variables=[\"items\"], \n",
+    "    template=template,\n",
+    "    template_format=\"jinja2\"\n",
+    ")"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 14,
+   "id": "ba8aabd3",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "'\\n\\nQuestion: foo\\nAnswer: bar\\n\\nQuestion: 1\\nAnswer: 2\\n'"
+      ]
+     },
+     "execution_count": 14,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "jinja2_prompt.format(items=items)"
+   ]
+  },
   {
    "cell_type": "markdown",
    "id": "1492b49d",
@@ -602,7 +655,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.7.6"
+   "version": "3.10.8"
   }
  },
  "nbformat": 4,

langchain/prompts/base.py

@@ -2,15 +2,30 @@
 import json
 from abc import ABC, abstractmethod
 from pathlib import Path
-from typing import Any, Dict, List, Optional, Union
+from typing import Any, Callable, Dict, List, Optional, Union
 
 import yaml
 from pydantic import BaseModel, Extra, root_validator
 
 from langchain.formatting import formatter
 
-DEFAULT_FORMATTER_MAPPING = {
+
+def jinja2_formatter(template: str, **kwargs: Any) -> str:
+    """Format a template using jinja2."""
+    try:
+        from jinja2 import Template
+    except ImportError:
+        raise ValueError(
+            "jinja2 not installed, which is needed to use the jinja2_formatter. "
+            "Please install it with `pip install jinja2`."
+        )
+
+    return Template(template).render(**kwargs)
+
+
+DEFAULT_FORMATTER_MAPPING: Dict[str, Callable] = {
     "f-string": formatter.format,
+    "jinja2": jinja2_formatter,
 }
 
 

langchain/prompts/few_shot.py

@@ -39,7 +39,7 @@ class FewShotPromptTemplate(BasePromptTemplate, BaseModel):
     """A prompt template string to put before the examples."""
 
     template_format: str = "f-string"
-    """The format of the prompt template. Options are: 'f-string'."""
+    """The format of the prompt template. Options are: 'f-string', 'jinja2'."""
 
     @root_validator(pre=True)
     def check_examples_and_selector(cls, values: Dict) -> Dict:

langchain/prompts/prompt.py

@@ -29,7 +29,7 @@ class PromptTemplate(BasePromptTemplate, BaseModel):
     """The prompt template."""
 
     template_format: str = "f-string"
-    """The format of the prompt template. Options are: 'f-string'."""
+    """The format of the prompt template. Options are: 'f-string', 'jinja2'."""
 
     class Config:
         """Configuration for this pydantic object."""

poetry.lock

@@ -2338,13 +2338,13 @@ docs = ["furo", "jaraco.packaging (>=9)", "jaraco.tidelift (>=1.4)", "rst.linker
 testing = ["flake8 (<5)", "func-timeout", "jaraco.functools", "jaraco.itertools", "more-itertools", "pytest (>=6)", "pytest-black (>=0.3.7)", "pytest-checkdocs (>=2.4)", "pytest-cov", "pytest-enabler (>=1.3)", "pytest-flake8", "pytest-mypy (>=0.9.1)"]
 
 [extras]
-all = ["manifest-ml", "elasticsearch", "faiss-cpu", "transformers", "spacy", "nltk", "wikipedia", "beautifulsoup4", "tiktoken", "torch"]
+all = ["manifest-ml", "elasticsearch", "faiss-cpu", "transformers", "spacy", "nltk", "wikipedia", "beautifulsoup4", "tiktoken", "torch", "jinja2"]
 llms = ["manifest-ml", "torch", "transformers"]
 
 [metadata]
 lock-version = "1.1"
 python-versions = ">=3.8.1,<4.0"
-content-hash = "d9ed2c5e1b2c51d7f8a9f74c858ab5058db14b7d6ca542777d7ecd07ccef5ee8"
+content-hash = "4099d88111a7f46857283d91c66fdfa7ed567461e8023509f2da86736a7ae24a"
 
 [metadata.files]
 anyio = [

pyproject.toml

@@ -22,7 +22,8 @@ spacy = {version = "^3", optional = true}
 nltk = {version = "^3", optional = true}
 transformers = {version = "^4", optional = true}
 beautifulsoup4 = {version = "^4", optional = true}
-torch = {version = "^1.13.1", optional = true}
+torch = {version = "^1", optional = true}
+jinja2 = {version = "^3", optional = true}
 tiktoken = {version = "^0", optional = true, python="^3.9"}
 
 [tool.poetry.group.test.dependencies]
@@ -51,7 +52,7 @@ playwright = "^1.28.0"
 
 [tool.poetry.extras]
 llms = ["cohere", "openai", "nlpcloud", "huggingface_hub", "manifest-ml", "torch", "transformers"]
-all = ["cohere", "openai", "nlpcloud", "huggingface_hub", "manifest-ml", "elasticsearch", "google-search-results", "faiss-cpu", "sentence_transformers", "transformers", "spacy", "nltk", "wikipedia", "beautifulsoup4", "tiktoken", "torch"]
+all = ["cohere", "openai", "nlpcloud", "huggingface_hub", "manifest-ml", "elasticsearch", "google-search-results", "faiss-cpu", "sentence_transformers", "transformers", "spacy", "nltk", "wikipedia", "beautifulsoup4", "tiktoken", "torch", "jinja2"]
 
 [tool.isort]
 profile = "black"