[PDF] Dan Murphy: «...TECO continued to be heavily used and enhanced by the hackers in Minsky’s AI lab, eventually including Richard Stallman.In the early to mid-1970s, Stallman would make some key enhancements to TECO that allowed it to become a fully interactive, WYSIWYG-style onscreen editor [...] This became the original Editor Macros (Emacs). TECO would continue to be the text engine for EMACS for several years, but it was ultimately replaced by a Lisp-like text manipulation language known as Emacs-Lisp...» — via emacs-devel (29 Apr 2010) —