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The Context filter is used to create regular expression context delimiters for filtering out content you want from content you don't want. Depending on how the filter is configured, the opening delimiter will swap from ignoring text to gathering text. When the closing delimiter is met, the filter will swap back from gathering text to ignoring text. If context_visible_first is set to true, the logic will be reversed.

Regular expressions are compiled with the MULTILINE flag so that ^ represents the start of a line and $ represents the end of a line. \A and \Z would represent the start and end of the buffer.

Delimiters require an open and a close pattern. You can optionally define a content pattern, but if you don't, it is .*? by default. The three patterns are used to create a single regular expression in the form r'{0}(?P<special_group_name>{1})(?:{2}|\Z)', where {0} is the opening pattern is inserted, {1} is the content pattern , and {2} is the closing pattern. special_group_name is randomly generated to ensure it doesn't conflict with anything in the pattern. Keeping in mind that these are all compiled into one pattern, you are able to define capture group names in opening, and reference them in the closing if needed.

You can also able to define a global escape pattern to prevent escaped delimiters from being captured.

The filter can be included via pyspelling.filters.context.

- name: python
  - pyspelling
  - pyspelling.filters.python:
      comments: false
  - pyspelling.filters.context_filter:
      context_visible_first: true
      escapes: '\\[\\`~]'
      # Ignore multiline content between fences (fences can have 3 or more back ticks)
      # ```
      # content
      # ```
      - open: '(?s)^(?P<open> *`{3,})$'
        close: '^(?P=open)$'
      # Ignore text between inline back ticks
      - open: '(?P<open>`+)'
        close: '(?P=open)'


Options Type Default Description
escapes string '' Regular expression pattern for character escapes outside delimiters.
context_visible_first bool False Context will start as invisible and will be invisible between delimiters.
delimiters [dict] [] A list of dicts that define the regular expression delimiters.


Context returns text with the following categories.

Category Description
context Text captured by the via context.

Last update: March 16, 2020