add pretty printing for regex patterns

src/pycalver/pysix.py

@@ -0,0 +1,42 @@
+import sys
+import typing as typ
+
+PY2 = sys.version < "3"
+
+
+try:
+    from urllib.parse import quote as py3_stdlib_quote
+except ImportError:
+    from urllib import quote as py2_stdlib_quote  # type: ignore
+
+
+# NOTE (mb 2016-05-23): quote in python2 expects bytes argument.
+
+
+def quote(
+    string  : str,
+    safe    : str = "/",
+    encoding: typ.Optional[str] = None,
+    errors  : typ.Optional[str] = None,
+) -> str:
+    if not isinstance(string, str):
+        errmsg = f"Expected str/unicode but got {type(string)}"  # type: ignore
+        raise TypeError(errmsg)
+
+    if encoding is None:
+        _encoding = "utf-8"
+    else:
+        _encoding = encoding
+
+    if errors is None:
+        _errors = "strict"
+    else:
+        _errors = errors
+
+    if PY2:
+        data = string.encode(_encoding)
+
+        res = py2_stdlib_quote(data, safe=safe.encode(_encoding))
+        return res.decode(_encoding, errors=_errors)
+    else:
+        return py3_stdlib_quote(string, safe=safe, encoding=_encoding, errors=_errors)