Add some builtin types methods

crates/erg_compiler/lib/std/_erg_bool.py

@@ -1,4 +1,5 @@
 from _erg_nat import Nat
+from _erg_nat import NatMut
 from _erg_result import Error
 
 class Bool(Nat):
@@ -15,3 +16,27 @@ class Bool(Nat):
             return "False"
     def __repr__(self) -> str:
         return self.__str__()
+    def mutate(self):
+        return BoolMut(self)
+    def invert(self):
+        return Bool(not self)
+
+class BoolMut(NatMut):
+    value: Bool
+
+    def __init__(self, b: Bool):
+        self.value = b
+    def __repr__(self):
+        return self.value.__repr__()
+    def __eq__(self, other):
+        if isinstance(other, bool):
+            return self.value == other
+        else:
+            return self.value == other.value
+    def __ne__(self, other):
+        if isinstance(other, bool):
+            return self.value != other
+        else:
+            return self.value != other.value
+    def invert(self):
+        self.value = self.value.invert()

crates/erg_compiler/lib/std/_erg_str.py

@@ -19,6 +19,8 @@ class Str(str):
         return StrMut(self)
     def to_int(self):
         return Int(self) if self.isdigit() else None
+    def contains(self, s):
+        return s in self
     def __add__(self, other):
         return then__(str.__add__(self, other), Str)
     def __radd__(self, other):