Use functions to implement validators

nonebot/command/argfilter/validators.py

@@ -1,7 +1,7 @@
 import re
 from typing import Callable, Any
 
-from nonebot.command.argfilter import ValidateError
+from nonebot.command.argfilter import ValidateError, ArgFilter_T
 
 
 class BaseValidator:
@@ -12,90 +12,88 @@ class BaseValidator:
         raise ValidateError(self.message)
 
 
-class not_empty(BaseValidator):
+def _raise_failure(message):
+    raise ValidateError(message)
+
+
+def not_empty(message=None) -> ArgFilter_T:
     """
     Validate any object to ensure it's not empty (is None or has no elements).
     """
 
-    def __call__(self, value):
+    def validate(value):
         if value is None:
-            self.raise_failure()
+            _raise_failure(message)
         if hasattr(value, '__len__') and value.__len__() == 0:
-            self.raise_failure()
+            _raise_failure(message)
         return value
 
+    return validate
 
-class fit_size(BaseValidator):
+
+def fit_size(min_length: int = 0, max_length: int = None,
+             message=None) -> ArgFilter_T:
     """
     Validate any sized object to ensure the size/length
     is in a given range [min_length, max_length].
     """
 
-    def __init__(self, min_length: int = 0, max_length: int = None,
-                 message=None):
-        super().__init__(message)
-        self.min_length = min_length
-        self.max_length = max_length
-
-    def __call__(self, value):
+    def validate(value):
         length = len(value) if value is not None else 0
-        if length < self.min_length or \
-                (self.max_length is not None and length > self.max_length):
-            self.raise_failure()
+        if length < min_length or \
+                (max_length is not None and length > max_length):
+            _raise_failure(message)
         return value
 
+    return validate
 
-class match_regex(BaseValidator):
+
+def match_regex(pattern: str, message=None, *, flags=0,
+                fullmatch: bool = False) -> ArgFilter_T:
     """
     Validate any string object to ensure it matches a given pattern.
     """
 
-    def __init__(self, pattern: str, message=None, *, flags=0,
-                 fullmatch: bool = False):
-        super().__init__(message)
-        self.pattern = re.compile(pattern, flags)
-        self.fullmatch = fullmatch
+    pattern = re.compile(pattern, flags)
 
-    def __call__(self, value):
-        if self.fullmatch:
-            if not re.fullmatch(self.pattern, value):
-                self.raise_failure()
+    def validate(value):
+        if fullmatch:
+            if not re.fullmatch(pattern, value):
+                _raise_failure(message)
         else:
-            if not re.match(self.pattern, value):
-                self.raise_failure()
+            if not re.match(pattern, value):
+                _raise_failure(message)
         return value
 
+    return validate
 
-class ensure_true(BaseValidator):
+
+def ensure_true(bool_func: Callable[[Any], bool],
+                message=None) -> ArgFilter_T:
     """
     Validate any object to ensure the result of applying
     a boolean function to it is True.
     """
 
-    def __init__(self, bool_func: Callable[[Any], bool], message=None):
-        super().__init__(message)
-        self.bool_func = bool_func
-
-    def __call__(self, value):
-        if self.bool_func(value) is not True:
-            self.raise_failure()
+    def validate(value):
+        if bool_func(value) is not True:
+            _raise_failure(message)
         return value
 
+    return validate
 
-class between_inclusive(BaseValidator):
+
+def between_inclusive(start=None, end=None, message=None) -> ArgFilter_T:
     """
     Validate any comparable object to ensure it's between
     `start` and `end` inclusively.
     """
 
-    def __init__(self, start=None, end=None, message=None):
-        super().__init__(message)
-        self.start = start
-        self.end = end
-
-    def __call__(self, value):
-        if self.start is not None and value < self.start:
-            self.raise_failure()
-        if self.end is not None and self.end < value:
-            self.raise_failure()
+    def validate(value):
+        if start is not None and value < start:
+            _raise_failure(message)
+        if end is not None and end < value:
+            _raise_failure(message)
         return value
+
+    return validate