File size: 8,386 Bytes
6059138 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 | from __future__ import annotations
import ast
import operator
import re
from dataclasses import dataclass
from typing import Callable
from langchain_core.messages import HumanMessage, SystemMessage
from langchain_mistralai import ChatMistralAI
from memory_agent.retrieval import HybridRetriever
from memory_agent.storage import FaissMemoryStore
FALLBACK_MESSAGE = (
"I don't have enough stored knowledge yet to answer that. "
"Share a few facts about your domain, and I will learn and help."
)
UNDERSTOOD_MESSAGE = "understood"
@dataclass(slots=True)
class ParsedFact:
key: str
value: str
class FactParser:
_ASSIGNMENT_PATTERNS = (
re.compile(r"^\s*([A-Za-z][A-Za-z0-9 _-]{0,80})\s*(?:=|:|is)\s*(.+?)\s*$", re.IGNORECASE),
re.compile(
r"^\s*(?:set|update|remember)\s+(.+?)\s+(?:to|as|=)\s+(.+?)\s*$",
re.IGNORECASE,
),
)
def parse(self, text: str) -> ParsedFact | None:
for pattern in self._ASSIGNMENT_PATTERNS:
match = pattern.match(text)
if not match:
continue
key = self._clean_key(match.group(1))
value = self._clean_value(match.group(2))
if key and value:
return ParsedFact(key=key, value=value)
return None
@staticmethod
def _clean_key(raw: str) -> str:
cleaned = raw.strip().strip(".")
cleaned = re.sub(r"\b(the|a|an)\b", "", cleaned, flags=re.IGNORECASE)
cleaned = re.sub(r"\s+", " ", cleaned)
return cleaned.strip()
@staticmethod
def _clean_value(raw: str) -> str:
cleaned = raw.strip().strip(".").strip()
if (cleaned.startswith('"') and cleaned.endswith('"')) or (
cleaned.startswith("'") and cleaned.endswith("'")
):
return cleaned[1:-1].strip()
return cleaned
class SafeMathEvaluator:
_BINARY_OPERATORS: dict[type[ast.operator], Callable[[float, float], float]] = {
ast.Add: operator.add,
ast.Sub: operator.sub,
ast.Mult: operator.mul,
ast.Div: operator.truediv,
ast.Pow: operator.pow,
ast.Mod: operator.mod,
ast.FloorDiv: operator.floordiv,
}
_UNARY_OPERATORS: dict[type[ast.unaryop], Callable[[float], float]] = {
ast.UAdd: operator.pos,
ast.USub: operator.neg,
}
def evaluate(self, expression: str, facts: dict[str, str]) -> float:
tree = ast.parse(expression, mode="eval")
return float(self._evaluate_node(tree.body, facts))
def _evaluate_node(self, node: ast.AST, facts: dict[str, str]) -> float:
if isinstance(node, ast.Constant) and isinstance(node.value, (int, float)):
return float(node.value)
if isinstance(node, ast.Name):
key = FaissMemoryStore.normalize_key(node.id)
if key not in facts:
raise ValueError(f"Unknown variable: {node.id}")
try:
return float(facts[key])
except ValueError as error:
raise ValueError(f"Variable '{node.id}' is not numeric.") from error
if isinstance(node, ast.BinOp):
op_type = type(node.op)
if op_type not in self._BINARY_OPERATORS:
raise ValueError("Unsupported operator in expression.")
left = self._evaluate_node(node.left, facts)
right = self._evaluate_node(node.right, facts)
return self._BINARY_OPERATORS[op_type](left, right)
if isinstance(node, ast.UnaryOp):
op_type = type(node.op)
if op_type not in self._UNARY_OPERATORS:
raise ValueError("Unsupported unary operator in expression.")
operand = self._evaluate_node(node.operand, facts)
return self._UNARY_OPERATORS[op_type](operand)
raise ValueError("Unsupported expression.")
class KnowledgeService:
def __init__(
self,
store: FaissMemoryStore,
retriever: HybridRetriever,
llm: ChatMistralAI,
top_k: int,
user_prompt_template: str,
) -> None:
self._store = store
self._retriever = retriever
self._llm = llm
self._top_k = top_k
self._user_prompt_template = user_prompt_template
self._fact_parser = FactParser()
self._math_evaluator = SafeMathEvaluator()
def store_knowledge(
self,
namespace: str,
knowledge_text: str,
fact_key: str | None = None,
fact_value: str | None = None,
) -> str:
parsed_fact = self._fact_parser.parse(knowledge_text)
key = fact_key or (parsed_fact.key if parsed_fact else None)
value = fact_value or (parsed_fact.value if parsed_fact else None)
content = knowledge_text
if key and value:
content = f"{key} = {value}"
self._store.upsert_knowledge(
namespace=namespace,
content=content,
fact_key=key,
fact_value=value,
)
return UNDERSTOOD_MESSAGE
def answer_from_knowledge(self, namespace: str, question: str) -> str:
facts = self._store.fetch_fact_map(namespace=namespace)
expression = self._extract_expression(question=question)
if expression:
try:
value = self._math_evaluator.evaluate(expression=expression, facts=facts)
formatted_value = int(value) if value.is_integer() else round(value, 6)
substituted = self._substitute_expression(expression=expression, facts=facts)
return f"Based on stored knowledge: {substituted} = {formatted_value}."
except ValueError:
pass
results = self._retriever.retrieve(namespace=namespace, query=question, k=self._top_k)
if not results:
return FALLBACK_MESSAGE
context = "\n\n".join(
f"- {doc.page_content}\n metadata={doc.metadata}"
for doc, _ in results
)
prompt = self._user_prompt_template.format(
fallback_message=FALLBACK_MESSAGE,
context=context,
question=question,
)
response = self._llm.invoke(
[
SystemMessage(content="You are a memory-only answer tool."),
HumanMessage(content=prompt),
]
)
content = str(response.content).strip()
if not content:
return FALLBACK_MESSAGE
return content
@staticmethod
def _extract_expression(question: str) -> str | None:
quoted = re.findall(r'["\']([^"\']+)["\']', question)
for candidate in quoted:
if re.search(r"[+\-*/^%()]", candidate):
return candidate.replace("^", "**")
inline = re.search(
r"(?:calculate|equation|expression)\s*[:\-,]?\s*([A-Za-z0-9_+\-*/^%(). ]+)",
question,
flags=re.IGNORECASE,
)
if inline:
expression = inline.group(1).strip().rstrip(".")
fragment = re.search(
r"((?:[A-Za-z_][A-Za-z0-9_]*|\d+(?:\.\d+)?|\([^)]+\))\s*"
r"(?:[+\-*/^%]\s*(?:[A-Za-z_][A-Za-z0-9_]*|\d+(?:\.\d+)?|\([^)]+\))\s*)+)",
expression,
flags=re.IGNORECASE,
)
if fragment:
return fragment.group(1).strip().replace("^", "**")
if re.search(r"[+\-*/^%()]", expression):
return expression.replace("^", "**")
fragment = re.search(
r"((?:[A-Za-z_][A-Za-z0-9_]*|\d+(?:\.\d+)?|\([^)]+\))\s*"
r"(?:[+\-*/^%]\s*(?:[A-Za-z_][A-Za-z0-9_]*|\d+(?:\.\d+)?|\([^)]+\))\s*)+)",
question,
flags=re.IGNORECASE,
)
if fragment:
return fragment.group(1).strip().replace("^", "**")
return None
@staticmethod
def _substitute_expression(expression: str, facts: dict[str, str]) -> str:
substituted = expression
# Replace longer keys first so short keys do not partially replace longer names.
for key in sorted(facts.keys(), key=len, reverse=True):
value = facts[key]
pattern = re.compile(rf"\b{re.escape(key)}\b", flags=re.IGNORECASE)
substituted = pattern.sub(value, substituted)
return substituted
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