feat: Add tactic object

pantograph/expr.py

@@ -2,7 +2,7 @@
 Data structuers for expressions and goals
 """
 from dataclasses import dataclass
-from typing import Optional, Self
+from typing import Optional, Self, Union
 
 Expr = str
 
@@ -60,3 +60,12 @@ class GoalState:
     @property
     def is_solved(self) -> bool:
         return not self.goals
+
+@dataclass(frozen=True)
+class TacticNormal:
+    payload: str
+@dataclass(frozen=True)
+class TacticHave:
+    branch: str
+
+Tactic = Union[TacticNormal, TacticHave]

pantograph/server.py

@@ -3,7 +3,7 @@ Class which manages a Pantograph instance. All calls to the kernel uses this
 interface.
 """
 import json, pexpect, pathlib, unittest
-from pantograph.expr import Variable, Goal, GoalState
+from pantograph.expr import Variable, Goal, GoalState, Tactic, TacticNormal
 
 def _get_proc_cwd():
     return pathlib.Path(__file__).parent
@@ -65,9 +65,13 @@ class Server:
             raise ServerError(result["desc"])
         return GoalState(state_id = result["stateId"], goals = [Goal.sentence(expr)])
 
-    def goal_tactic(self, state: GoalState, goalId: int, tactic: str) -> GoalState:
+    def goal_tactic(self, state: GoalState, goalId: int, tactic: Tactic) -> GoalState:
-        result = self.run('goal.tactic', {
+        args = { "stateId": state.state_id, "goalId": goalId }
-            "stateId": state.state_id, "goalId": goalId, "tactic": tactic})
+        if isinstance(tactic, TacticNormal):
+            args["tactic"] = tactic.payload
+        else:
+            raise Exception(f"Invalid tactic type: {tactic}")
+        result = self.run('goal.tactic', args)
         if "error" in result:
             raise ServerError(result["desc"])
         if "tacticErrors" in result:
@@ -95,7 +99,7 @@ class TestServer(unittest.TestCase):
         server = Server()
         state0 = server.goal_start("forall (p q: Prop), Or p q -> Or q p")
         self.assertEqual(state0.state_id, 0)
-        state1 = server.goal_tactic(state0, goalId=0, tactic="intro a")
+        state1 = server.goal_tactic(state0, goalId=0, tactic=TacticNormal("intro a"))
         self.assertEqual(state1.state_id, 1)
         self.assertEqual(state1.goals, [Goal(
             variables=[Variable(name="a", t="Prop")],