The ABNF editor provides many features helping grammar authoring in an effective way, including:

• Intelligent insertion of delimiters. For example:
  • Typing an opening parenthesis inserts a matching closing parenthesis.
  • Typing a closing delimiter when the cursor is in front of a similar delimiter simply moves the cursor past the delimiter. (Delimiters include parentheses, square brackets for optional items, curly brackets for semantic tags, and double quotes.)
  • Typing an opening delimiter while there is a selection active inserts matching delimiters around the selected text.
• Matching of delimiters. When the cursor is positioned just before an opening delimiter, the corresponding closing delimiter is highlighted.
• Double-click strategy. Double-clicking on an opening (or closing) delimiter selects the region between (and including) the delimiter and its corresponding closing (resp. opening) delimiter.
• Syntax coloring. Each syntactic element may be given a different color or text attribute to help visualize the structure of the grammar and its various constituents.
• Rule folding. Rule definitions may be individually collapsed or expanded.
• Rule hyperlinks. Moving the mouse over a rule name while keeping the Control key pressed shows an hyperlink. Clicking on the hyperlink moves the cursor to the rule definition.