https://www.gutenberg.org/ebooks/5768
Guy Steele expresses similar admiration. Currently a research scientist for Sun Microsystems, he remembers Stallman primarily as a "brilliant programmer with the ability to generate large quantities of relatively bug-free code." Although their personalities didn't exactly mesh, Steele and Stallman collaborated long enough for Steele to get a glimpse of Stallman's intense coding style. He recalls a notable episode in the late 1970s when the two programmers banded together to write the editor's "pretty print" feature. Originally conceived by Steele, pretty print was another keystroke-triggerd feature that reformatted Emacs' source code so that it was both more readable and took up less space, further bolstering the program's WYSIWIG qualities. The feature was strategic enough to attract Stallman's active interest, and it wasn't long before Steele wrote that he and Stallman were planning an improved version.
"We sat down one morning," recalls Steele. "I was at the keyboard, and he was at my elbow," says Steele. "He was perfectly willing to let me type, but he was also telling me what to type.
The programming session lasted 10 hours. Throughout that entire time, Steele says, neither he nor Stallman took a break or made any small talk. By the end of the session, they had managed to hack the pretty print source code to just under 100 lines. "My fingers were on the keyboard the whole time," Steele recalls, "but it felt like both of our ideas were flowing onto the screen. He told me what to type, and I typed it."
The length of the session revealed itself when Steele finally left the AI Lab. Standing outside the building at 545 Tech Square, he was surprised to find himself surrounded by nighttime darkness. As a programmer, Steele was used to marathon coding sessions. Still, something about this session was different. Working with Stallman had forced Steele to block out all external stimuli and focus his entire mental energies on the task at hand. Looking back, Steele says he found the Stallman mind-meld both exhilarating and scary at the same time. "My first thought afterward was: it was a great experience, very intense, and that I never wanted to do it again in my life."