config: start adding support of multiline values

mylib/config.py

@@ -189,7 +189,7 @@ class BaseOption:  # pylint: disable=too-many-instance-attributes
         """ Export option to configuration file """
         lines = []
         if self.comment:
-            lines.append('# ' + self.comment)
+            lines.append(f'# {self.comment}')
         value = self.to_config()
         default_value = (
             '' if self.default is None else
@@ -199,28 +199,41 @@ class BaseOption:  # pylint: disable=too-many-instance-attributes
             'export_to_config(%s, %s): value=%s / default=%s',
             self.section.name, self.name, value, default_value)
         if default_value:
+            if isinstance(default_value, str) and '\n' in default_value:
+                lines.append('# Default:')
+                lines.extend([f'#    {line}' for line in default_value.split('\n')])
+            else:
                 lines.append(
-                '# Default: %s' % default_value
+                    f'# Default: {default_value}'
                 )
         if value and value != default_value:
+            if isinstance(value, str) and '\n' in value:
+                value_lines = value.split('\n')
+                lines.append(f'# Default: {value_lines[0]}')
+                lines.extend([f'    {line.replace("#", "%(hash)s")}' for line in value_lines[1:]])
+            else:
                 lines.append(
-                '%s = %s' %
-                (self.name, value)
+                    f'{self.name} = {value}'
                 )
         else:
-            lines.append('# %s =' % self.name)
+            lines.append(f'# {self.name} =')
         lines.append('')
         return '\n'.join(lines)
 
     def _ask_value(self, prompt=None, **kwargs):
         """ Ask to user to enter value of this option and return it """
         if self.comment:
-            print('# ' + self.comment)
+            print(f'# {self.comment}')
         default_value = kwargs.get('default_value', self.get())
         if not prompt:
-            prompt = "%s: " % self.name
+            prompt = f'{self.name}: '
             if default_value is not None:
-                prompt += "[%s] " % self.to_config(default_value)
+                if isinstance(default_value, str) and '\n' in default_value:
+                    prompt += "[\n    %s\n] " % "\n    ".join(
+                        self.to_config(default_value).split('\n')
+                    )
+                else:
+                    prompt += f'[{self.to_config(default_value)}] '
         value = input(prompt)
         return default_value if value == '' else value
 
@@ -646,7 +659,7 @@ class Config:  # pylint: disable=too-many-instance-attributes
     def load_file(self, filepath, execute_callback=True):
         """ Read configuration file """
 
-        self.config_parser = ConfigParser()
+        self.config_parser = ConfigParser(defaults={'hash': '#'})
         self._filepath = filepath
 
         # Checking access of configuration file