Remove default values on type declarations and mark ClassVars

lark/common.py

@@ -17,12 +17,12 @@ class LexerConf(Serialize):
 
     terminals: Collection[TerminalDef]
     re_module: ModuleType
-    ignore: Collection[str] = ()
-    postlex: 'Optional[PostLex]' = None
-    callbacks: Dict[str, _Callback] = {}
-    g_regex_flags: int = 0
-    skip_validation: bool = False
-    use_bytes: bool = False
+    ignore: Collection[str]
+    postlex: 'Optional[PostLex]'
+    callbacks: Dict[str, _Callback]
+    g_regex_flags: int
+    skip_validation: bool
+    use_bytes: bool
 
     def __init__(self, terminals: Collection[TerminalDef], re_module: ModuleType, ignore: Collection[str]=(), postlex: 'Optional[PostLex]'=None, callbacks: Optional[Dict[str, _Callback]]=None, g_regex_flags: int=0, skip_validation: bool=False, use_bytes: bool=False):
         self.terminals = terminals

lark/grammar.py

@@ -3,13 +3,13 @@ from .utils import Serialize
 
 ###{standalone
 
-from typing import Optional, Tuple
+from typing import Optional, Tuple, ClassVar
 
 class Symbol(Serialize):
     __slots__ = ('name',)
 
     name: str
-    is_term: bool = NotImplemented
+    is_term: ClassVar[bool] = NotImplemented
 
     def __init__(self, name: str) -> None:
         self.name = name
@@ -33,7 +33,7 @@ class Symbol(Serialize):
 class Terminal(Symbol):
     __serialize_fields__ = 'name', 'filter_out'
 
-    is_term = True
+    is_term: ClassVar[bool] = True
 
     def __init__(self, name, filter_out=False):
         self.name = name
@@ -47,7 +47,7 @@ class Terminal(Symbol):
 class NonTerminal(Symbol):
     __serialize_fields__ = 'name',
 
-    is_term = False
+    is_term: ClassVar[bool] = False
 
 
 class RuleOptions(Serialize):

lark/lexer.py

@@ -13,7 +13,7 @@ from copy import copy
 from types import ModuleType
 from typing import (
     TypeVar, Type, Tuple, List, Dict, Iterator, Collection, Callable, Optional, FrozenSet, Any,
-    Pattern as REPattern, TYPE_CHECKING
+    Pattern as REPattern, ClassVar, TYPE_CHECKING
 )
 
 if TYPE_CHECKING:
@@ -23,8 +23,8 @@ class Pattern(Serialize, ABC):
 
     value: str
     flags: Collection[str]
-    raw: Optional[str] = None
-    type: Optional[str] = None
+    raw: Optional[str]
+    type: ClassVar[str]
 
     def __init__(self, value: str, flags: Collection[str]=(), raw: Optional[str]=None) -> None:
         self.value = value
@@ -73,7 +73,7 @@ class Pattern(Serialize, ABC):
 class PatternStr(Pattern):
     __serialize_fields__ = 'value', 'flags'
 
-    type: str = "str"
+    type: ClassVar[str] = "str"
 
     def to_regexp(self) -> str:
         return self._get_flags(re.escape(self.value))
@@ -90,7 +90,7 @@ class PatternStr(Pattern):
 class PatternRE(Pattern):
     __serialize_fields__ = 'value', 'flags', '_width'
 
-    type: str = "re"
+    type: ClassVar[str] = "re"
 
     def to_regexp(self) -> str:
         return self._get_flags(self.value)