Text editing

As all programs are ultimately displayed by ctedit's, text fragments edited outside of a ctedit must be parsed before pieces of abstract syntax tree may be redisplayed in a ctedit. After using any of the following text editing facilities, text is reparsed and, if correct, inserted at the current location.

• Emacs: Ctedit's may communicate with external editor processes such as GnuEmacs. Through the graphic interface, you may select a program fragment, send it to GnuEmacs, and from GnuEmacs, have the modified text parsed and sent back to the source ctedit.

  To connect GnuEmacs with Centaur, first you must include the following line in your .emacs file to enable the Centaur/GnuEmacs connection: (load "/etc/centaur.el")

  Then, open a special Centaur buffer in GnuEmacs by typing Escape-x, then editor-start. You are asked to enter the name of the Centaur session. By default, this name is centaur, so you may just type a carriage return. Then, to send the currently selected subtree from a ctedit to GnuEmacs, click on the button of the Edit pulldown. If you have selected less than the entire program, the phylum name appears between brackets at the head of the text. The phylum name must not be edited. You may edit the text and send it back to replace the current select by typing ^x^s. If a parsing error occurs, the text remains unchanged in the ctview. You may also insert the new text before or after the current selection with the keystrokes ^x^i and ^x^a respectively.

• In-line editing: Rather than send text back and forth between ctedit and emacs, it is possible to edit fragments of text in place in a ctedit. You must enter a special in-line mode and type text directly in the ctedit (standard editing commands available) at a selected location. Leaving the in-line mode has the modified text parsed and, if correct, inserted at the current location. To enter in-line editing mode, type ^e. You may then edit the current selection with GnuEmacs-like keystrokes to go to the beginning of the selected text, cut until the end of the line, etc. To leave and reparse the modified text, press the Escape button.
• X selection: One may use the X selection to transfer text from any X window to a ctedit; the text is parsed and, if correct, inserted at the current location.