X-Git-Url: https://git.madduck.net/etc/vim.git/blobdiff_plain/e401b6bb1e1c0ed534bba59d9dc908caf7ba898c..e9681a40dcb3d38b56b301d811bb1c55201fd97e:/src/black/mode.py

diff --git a/src/black/mode.py b/src/black/mode.py
index 5e04525..6b74c14 100644
--- a/src/black/mode.py
+++ b/src/black/mode.py
@@ -4,12 +4,14 @@ Mostly around Python language feature support per version and Black configuratio
 chosen by the user.
 """
 
+from hashlib import sha256
 import sys
 
 from dataclasses import dataclass, field
-from enum import Enum
+from enum import Enum, auto
 from operator import attrgetter
 from typing import Dict, Set
+from warnings import warn
 
 if sys.version_info < (3, 8):
     from typing_extensions import Final
@@ -121,6 +123,18 @@ def supports_feature(target_versions: Set[TargetVersion], feature: Feature) -> b
     return all(feature in VERSION_TO_FEATURES[version] for version in target_versions)
 
 
+class Preview(Enum):
+    """Individual preview style features."""
+
+    string_processing = auto()
+    remove_redundant_parens = auto()
+    one_element_subscript = auto()
+
+
+class Deprecated(UserWarning):
+    """Visible deprecation warning."""
+
+
 @dataclass
 class Mode:
     target_versions: Set[TargetVersion] = field(default_factory=set)
@@ -130,6 +144,27 @@ class Mode:
     is_ipynb: bool = False
     magic_trailing_comma: bool = True
     experimental_string_processing: bool = False
+    python_cell_magics: Set[str] = field(default_factory=set)
+    preview: bool = False
+
+    def __post_init__(self) -> None:
+        if self.experimental_string_processing:
+            warn(
+                "`experimental string processing` has been included in `preview`"
+                " and deprecated. Use `preview` instead.",
+                Deprecated,
+            )
+
+    def __contains__(self, feature: Preview) -> bool:
+        """
+        Provide `Preview.FEATURE in Mode` syntax that mirrors the ``preview`` flag.
+
+        The argument is not checked and features are not differentiated.
+        They only exist to make development easier by clarifying intent.
+        """
+        if feature is Preview.string_processing:
+            return self.preview or self.experimental_string_processing
+        return self.preview
 
     def get_cache_key(self) -> str:
         if self.target_versions:
@@ -147,5 +182,7 @@ class Mode:
             str(int(self.is_ipynb)),
             str(int(self.magic_trailing_comma)),
             str(int(self.experimental_string_processing)),
+            str(int(self.preview)),
+            sha256((",".join(sorted(self.python_cell_magics))).encode()).hexdigest(),
         ]
         return ".".join(parts)