correct formal objects equality

Author: bygu4

pyformlang/objects/base_epsilon.py

@@ -30,3 +30,6 @@ def __hash__(self) -> int:
 
     def __repr__(self) -> str:
         return "epsilon"
+
+    def _is_equal_to(self, other: FormalObject) -> bool:
+        return isinstance(other, BaseEpsilon)

pyformlang/objects/base_terminal.py

@@ -1,6 +1,5 @@
 """ General terminal representation """
 
-from typing import Any
 from abc import abstractmethod
 
 from .formal_object import FormalObject
@@ -9,16 +8,9 @@
 class BaseTerminal(FormalObject):
     """ General terminal representation """
 
-    def __eq__(self, other: Any) -> bool:
-        if isinstance(other, BaseTerminal):
-            return self.value == other.value
-        if isinstance(other, FormalObject):
-            return False
-        return self.value == other
-
-    def __hash__(self) -> int:
-        return super().__hash__()
-
     @abstractmethod
     def __repr__(self):
         raise NotImplementedError
+
+    def _is_equal_to(self, other: FormalObject) -> bool:
+        return isinstance(other, BaseTerminal) and self.value == other.value

pyformlang/objects/cfg_objects/variable.py

@@ -1,6 +1,5 @@
 """ A variable in a CFG """
 
-from typing import Any
 from string import ascii_uppercase
 
 from .cfg_object import CFGObject
@@ -16,16 +15,6 @@ class Variable(CFGObject):
         The value of the variable
     """
 
-    def __eq__(self, other: Any) -> bool:
-        if isinstance(other, Variable):
-            return self.value == other.value
-        if isinstance(other, FormalObject):
-            return False
-        return self.value == other
-
-    def __hash__(self) -> int:
-        return super().__hash__()
-
     def __repr__(self) -> str:
         return f"Variable({self})"
 
@@ -34,3 +23,6 @@ def to_text(self) -> str:
         if text and text[0] not in ascii_uppercase:
             return '"VAR:' + text + '"'
         return text
+
+    def _is_equal_to(self, other: FormalObject) -> bool:
+        return isinstance(other, Variable) and self.value == other.value

pyformlang/objects/finite_automaton_objects/state.py

@@ -2,8 +2,6 @@
 Representation of a state in a finite state automaton
 """
 
-from typing import Any
-
 from .finite_automaton_object import FiniteAutomatonObject
 from ..formal_object import FormalObject
 
@@ -24,15 +22,8 @@ class State(FiniteAutomatonObject):
 
     """
 
-    def __eq__(self, other: Any) -> bool:
-        if isinstance(other, State):
-            return self.value == other.value
-        if isinstance(other, FormalObject):
-            return False
-        return self.value == other
-
-    def __hash__(self) -> int:
-        return super().__hash__()
-
     def __repr__(self) -> str:
         return f"State({self})"
+
+    def _is_equal_to(self, other: FormalObject) -> bool:
+        return isinstance(other, State) and self.value == other.value

pyformlang/objects/formal_object.py

@@ -23,9 +23,10 @@ def value(self) -> Hashable:
         """
         return self._value
 
-    @abstractmethod
     def __eq__(self, other: Any) -> bool:
-        raise NotImplementedError
+        if not isinstance(other, FormalObject):
+            return self.value == other
+        return self._is_equal_to(other) and other._is_equal_to(self)
 
     def __hash__(self) -> int:
         if self._hash is None:
@@ -38,3 +39,7 @@ def __str__(self) -> str:
     @abstractmethod
     def __repr__(self) -> str:
         raise NotImplementedError
+
+    @abstractmethod
+    def _is_equal_to(self, other: "FormalObject") -> bool:
+        raise NotImplementedError

pyformlang/objects/pda_objects/stack_symbol.py

@@ -1,7 +1,5 @@
 """ A StackSymbol in a pushdown automaton """
 
-from typing import Any
-
 from .symbol import Symbol
 from ..formal_object import FormalObject
 
@@ -16,15 +14,8 @@ class StackSymbol(Symbol):
 
     """
 
-    def __eq__(self, other: Any) -> bool:
-        if isinstance(other, StackSymbol):
-            return self.value == other.value
-        if isinstance(other, FormalObject):
-            return False
-        return self.value == other
-
-    def __hash__(self) -> int:
-        return super().__hash__()
-
     def __repr__(self) -> str:
         return f"StackSymbol({self})"
+
+    def _is_equal_to(self, other: FormalObject) -> bool:
+        return isinstance(other, StackSymbol) and self.value == other.value

pyformlang/objects/pda_objects/state.py

@@ -1,7 +1,5 @@
 """ A State in a pushdown automaton """
 
-from typing import Any
-
 from .pda_object import PDAObject
 from ..formal_object import FormalObject
 
@@ -16,15 +14,8 @@ class State(PDAObject):
 
     """
 
-    def __eq__(self, other: Any) -> bool:
-        if isinstance(other, State):
-            return self.value == other.value
-        if isinstance(other, FormalObject):
-            return False
-        return self.value == other
-
-    def __hash__(self) -> int:
-        return super().__hash__()
-
     def __repr__(self) -> str:
         return f"State({self})"
+
+    def _is_equal_to(self, other: FormalObject) -> bool:
+        return isinstance(other, State) and self.value == other.value

pyformlang/pda/tests/test_pda.py

@@ -389,6 +389,8 @@ def test_object_eq(self):
         assert StackSymbol("ABC") != Symbol("ABC")
         assert State("ABC") != FAState("ABC")
         assert Symbol("s") == Terminal("s")
+        assert Terminal(1) != StackSymbol(1)
+        assert StackSymbol(42) != FAState(42)
 
     def test_contains(self, pda_example: PDA):
         """ Tests the transition containment checks """