--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/service/mqtt_to_rdf/inference.py	Sun Aug 29 23:59:09 2021 -0700
@@ -0,0 +1,83 @@
+"""
+copied from reasoning 2021-08-29. probably same api. should
+be able to lib/ this out
+"""
+
+import logging
+from typing import Dict, Tuple
+from dataclasses import dataclass
+from prometheus_client import Summary
+from rdflib import Graph, Namespace
+from rdflib.graph import ConjunctiveGraph
+from rdflib.term import Node, Variable
+
+log = logging.getLogger('infer')
+
+Triple = Tuple[Node, Node, Node]
+Rule = Tuple[Graph, Node, Graph]
+
+READ_RULES_CALLS = Summary('read_rules_calls', 'calls')
+
+ROOM = Namespace("http://projects.bigasterisk.com/room/")
+LOG = Namespace('http://www.w3.org/2000/10/swap/log#')
+MATH = Namespace('http://www.w3.org/2000/10/swap/math#')
+
+
+@dataclass
+class _RuleMatch:
+    """one way that a rule can match the working set"""
+    vars: Dict[Variable, Node]
+
+
+class Inference:
+
+    def __init__(self) -> None:
+        self.rules = ConjunctiveGraph()
+
+    def setRules(self, g: ConjunctiveGraph):
+        self.rules = g
+
+    def infer(self, graph: Graph):
+        """
+        returns new graph of inferred statements.
+        """
+        log.info(f'Begin inference of graph len={len(graph)} with rules len={len(self.rules)}:')
+
+        workingSet = ConjunctiveGraph()
+        if isinstance(graph, ConjunctiveGraph):
+            workingSet.addN(graph.quads())
+        else:
+            for triple in graph:
+                workingSet.add(triple)
+
+        implied = ConjunctiveGraph()
+
+        bailout_iterations = 100
+        delta = 1
+        while delta > 0 and bailout_iterations > 0:
+            bailout_iterations -= 1
+            delta = -len(implied)
+            self._iterateRules(workingSet, implied)
+            delta += len(implied)
+            log.info(f'  this inference round added {delta} more implied stmts')
+        log.info(f'{len(implied)} stmts implied:')
+        for st in implied:
+            log.info(f'  {st}')
+        return implied
+
+    def _iterateRules(self, workingSet, implied):
+        for r in self.rules:
+            if r[1] == LOG['implies']:
+                self._applyRule(r[0], r[2], workingSet, implied)
+            else:
+                log.info(f'  {r} not a rule?')
+
+    def _applyRule(self, lhs, rhs, workingSet, implied):
+        containsSetup = self._containsSetup(lhs, workingSet)
+        if containsSetup:
+            for st in rhs:
+                workingSet.add(st)
+                implied.add(st)
+
+    def _containsSetup(self, lhs, workingSet):
+        return all(st in workingSet for st in lhs)