Fix Python 3.6 DeprecationWarning invalid escape sequence messages

Fix by ensuring that regular expressions are constructed using either
raw string literals [1] or double backslashes [2].

[1] https://stackoverflow.com/questions/44325948/pandas-invalid-escape-sequence-after-update
[2] https://github.com/joblib/joblib/pull/526

Note that python only shows the deprecation warnings on initial run [3].

[3] https://bugs.python.org/issue30091

To work around this issue, remove the cached bytecode with:

    find . -name "__pycache__" -exec rm -rf {} \;

Then to prevent compiling to bytecode add the "-B" option to python:

    python3 -B -m pytest -vs

manuskript/ui/editors/themes.py

@@ -137,7 +137,7 @@ def createThemePreview(theme, screenRect, size=QSize(200, 120)):
 def findThemePath(themeName):
     p = findFirstFile(re.escape("{}.theme".format(themeName)), "resources/themes")
     if not p:
-        return findFirstFile(".*\.theme", "resources/themes")
+        return findFirstFile(r".*\.theme", "resources/themes")
     else:
         return p
 

manuskript/ui/highlighters/MMDHighlighter.py

@@ -11,19 +11,19 @@ from manuskript.ui.highlighters import BasicHighlighter
 class MMDHighlighter(BasicHighlighter):
 
     MARKDOWN_REGEX = {
-        'Bold':             '(\*\*)(.+?)(\*\*)',
+        'Bold':             r'(\*\*)(.+?)(\*\*)',
         'Bold2':            '(__)(.+?)(__)',
-        'Italic':           '(\*)([^\*].+?[^\*])(\*)',
+        'Italic':           r'(\*)([^\*].+?[^\*])(\*)',
         'Italic2':          '(_)([^_].+?[^_])(_)',
-        'Title':            '^(#+)(\s*)(.*)(#*)',
+        'Title':            r'^(#+)(\s*)(.*)(#*)',
         'HTML':             '<.+?>',
         'Blockquotes':      '^(> )+.*$',
-        'OrderedList':      '^\d+\.\s+',
-        'UnorderedList':    '^[\*\+-]\s+',
-        'Code':             '^\s{4,}.*$',
-        'Links-inline':     '(\[)(.*?)(\])(\()(.*?)(\))',
-        'Links-ref':        '(\[)(.*?)(\])\s?(\[)(.*?)(\])',
-        'Links-ref2':       '^\s{,3}(\[)(.*?)(\]:)\s+([^\s]*)\s*(.*?)*$',
+        'OrderedList':      r'^\d+\.\s+',
+        'UnorderedList':    r'^[\*\+-]\s+',
+        'Code':             r'^\s{4,}.*$',
+        'Links-inline':     r'(\[)(.*?)(\])(\()(.*?)(\))',
+        'Links-ref':        r'(\[)(.*?)(\])\s?(\[)(.*?)(\])',
+        'Links-ref2':       r'^\s{,3}(\[)(.*?)(\]:)\s+([^\s]*)\s*(.*?)*$',
     }
 
     def __init__(self, editor, style="Default"):

manuskript/ui/highlighters/markdownTokenizer.py

@@ -91,7 +91,7 @@ class MarkdownTokenizer(HighlightTokenizer):
     strongRegex.setMinimal(True)
     strikethroughRegex = QRegExp("~~[^\\s]+.*[^\\s]+~~")
     strikethroughRegex.setMinimal(True)
-    superScriptRegex = QRegExp("\^([^\\s]|(\\\\\\s))+\^")  # Spaces must be escaped "\ "
+    superScriptRegex = QRegExp(r"\^([^\s]|(\\\\\s))+\^")  # Spaces must be escaped "\ "
     superScriptRegex.setMinimal(True)
     subScriptRegex = QRegExp("~([^\\s]|(\\\\\\s))+~")  # Spaces must be escaped "\ "
     subScriptRegex.setMinimal(True)
@@ -887,7 +887,7 @@ class MarkdownTokenizer(HighlightTokenizer):
         with the escaped characters replaced with a dummy character.
         """
 
-        return re.sub("\\\\.", "\$", text)
+        return re.sub("\\\\.", r"\$", text)
 
         #escape = False
         #escapedText = text

manuskript/ui/views/MDEditView.py

@@ -18,7 +18,7 @@ from manuskript import functions as F
 class MDEditView(textEditView):
 
     blockquoteRegex = QRegExp("^ {0,3}(>\\s*)+")
-    listRegex = QRegExp("^(\\s*)([+*-]|([0-9a-z])+([.\)]))(\\s+)")
+    listRegex = QRegExp(r"^(\s*)([+*-]|([0-9a-z])+([.\)]))(\s+)")
     inlineLinkRegex = QRegExp("\\[([^\n]+)\\]\\(([^\n]+)\\)")
     imageRegex = QRegExp("!\\[([^\n]*)\\]\\(([^\n]+)\\)")
     automaticLinkRegex = QRegExp("(<([a-zA-Z]+\\:[^\n]+)>)|(<([^\n]+@[^\n]+)>)")
@@ -342,15 +342,15 @@ class MDEditView(textEditView):
     def clearedFormat(self, text):
         # FIXME: clear also block formats
         for reg, rep, flags in [
-            ("\*\*(.*?)\*\*", "\\1", None), # bold
+            (r"\*\*(.*?)\*\*", "\\1", None), # bold
             ("__(.*?)__", "\\1", None), # bold
-            ("\*(.*?)\*", "\\1", None), # emphasis
+            (r"\*(.*?)\*", "\\1", None), # emphasis
             ("_(.*?)_", "\\1", None), # emphasis
             ("`(.*?)`", "\\1", None), # verbatim
             ("~~(.*?)~~", "\\1", None), # strike
-            ("\^(.*?)\^", "\\1", None), # superscript
+            (r"\^(.*?)\^", "\\1", None), # superscript
             ("~(.*?)~", "\\1", None), # subscript
-            ("<!--\s*(.*?)\s*-->", "\\1", re.S), # comments
+            (r"<!--\s*(.*?)\s*-->", "\\1", re.S), # comments
 
             # LINES OR BLOCKS
             (r"^#*\s*(.+?)\s*", "\\1", re.M), # ATX
@@ -394,7 +394,7 @@ class MDEditView(textEditView):
             c.insertText("")
 
         char = "=" if level == 1 else "-"
-        text = re.sub("^#*\s*(.*)\s*#*", "\\1", text)  # Removes #
+        text = re.sub(r"^#*\s*(.*)\s*#*", "\\1", text)  # Removes #
         sub = char * len(text)
         text = text + "\n" + sub
 
@@ -429,7 +429,7 @@ class MDEditView(textEditView):
             self.titleATX(level)
             return
 
-        m = re.match("^(#+)(\s*)(.+)", text)
+        m = re.match(r"^(#+)(\s*)(.+)", text)
         if m:
             pre = m.group(1)
             space = m.group(2)