Long ago. BBN Lisp (later known as Xerox Interlisp) had already a structure editor in the 60s. http://www.softwarepreservation.org/projects/LISP/bbnlisp/BBN94

Long ago. BBN Lisp (later known as Xerox Interlisp) had already a structure editor in the 60s. http://www.softwarepreservation.org/projects/LISP/bbnlisp/BBN940Lisp_Jul67.pdf http://www.softwarepreservation.org/projects/LISP/bbnlisp/BB... see page 40ff. A lot of editing support was then developed in the 70s with the various Emacs editors (TECO Emacs, Zmacs, Multics Emacs, ...) or the Interlisp editors. In the 80s various Lisp IDEs had support for editing Lisp on PCs, Macs, Unix-Workstations, Lisp Machines, ...