Move shared sub/superscript regex to utility file

The subscript and superscript plugins both use the same regular
expressions. This commit standardizes and centralizes the regex into a
utility file.

Author: elijahgreenstein

mdit_py_plugins/subscript/__init__.py

@@ -10,21 +10,18 @@
 from __future__ import annotations
 
 from collections.abc import Sequence
-import re
 
 from markdown_it import MarkdownIt
 from markdown_it.renderer import RendererHTML
 from markdown_it.rules_inline import StateInline
 from markdown_it.token import Token
 from markdown_it.utils import EnvType, OptionsDict
+from mdit_py_plugins.utils import UNESCAPE_RE, WHITESPACE_RE
 
 __all__ = ["sub_plugin"]
 
 TILDE_CHAR = "~"
 
-WHITESPACE_RE = re.compile(r"(^|[^\\])(\\\\)*\s")
-UNESCAPE_RE = re.compile(r'\\([ \\!"#$%&\'()*+,.\/:;<=>?@[\]^_`{|}~-])')
-
 
 def tokenize(state: StateInline, silent: bool) -> bool:
     """Parse a ~subscript~ token."""

mdit_py_plugins/superscript/index.py

@@ -28,13 +28,9 @@
 OTHER DEALINGS IN THE SOFTWARE.
 """
 
-import re
-
 from markdown_it import MarkdownIt
 from markdown_it.rules_inline import StateInline
-
-UNESCAPE_RE = re.compile(r"\\([ \\!\"#$%&'()*+,./:;<=>?@[\]^_`{|}~-])")
-WHITESPACE_RE = re.compile(r"(^|[^\\])(\\\\)*\s")
+from mdit_py_plugins.utils import UNESCAPE_RE, WHITESPACE_RE
 
 
 def superscript_plugin(md: MarkdownIt) -> None:

mdit_py_plugins/utils.py

@@ -1,3 +1,5 @@
+import re
+
 from markdown_it.rules_block import StateBlock
 
 
@@ -10,3 +12,8 @@ def is_code_block(state: StateBlock, line: int) -> bool:
         pass
 
     return (state.sCount[line] - state.blkIndent) >= 4
+
+
+# Regex for subscript and superscript plugins
+UNESCAPE_RE = re.compile(r"\\([ \\!\"#$%&'()*+,./:;<=>?@[\]^_`{|}~-])")
+WHITESPACE_RE = re.compile(r"(^|[^\\])(\\\\)*\s")