You can use any third-party edit control available as jQuery plugin in data input forms. Typically all you need is to write a small function in JavaScript that initializes the editor and call this function from OnInsertFormLoaded and OnEditFormLoaded event handlers.

The page below allows you to edit the contents of the function_code field using the CodeMirror editor that provides syntax highlighting, code folding, autocompletion, and other useful features. Open Insert or Edit forms to see the editor in action.