Sunday, April 3, 2016

The Deep History of Your Apps

Hansen Hsu (via Andrew Wooster, comments):

During Jobs’ visit to PARC, he had been so enthralled by the surface details of the GUI that he completely missed the radical way it had been created with objects. The result was that programming graphical applications on the Macintosh would become much more difficult than doing so with Smalltalk. Said Jobs in his 1988 introduction of the NeXT Computer: “Macintosh was a revolution in making it easier for the end user. But the software developer paid the price… It is a bear to develop software… for the Macintosh… if you look at the time it takes to make [a GUI] application… the user interface takes 90% of the time.”

With the NeXT computer, Jobs planned to fix this exact shortcoming of the Macintosh. The PARC technologies missing from the Mac would become central features on the NeXT. NeXT computers, like other workstations, were designed to live in a permanently networked environment. Jobs called this “inter-personal computing,” though it was simply a renaming of what Xerox’s Thacker and Lampson called “personal distributed computing.” Likewise, dynamic object-oriented programming on the Smalltalk model provided the basis for all software development on NeXTSTEP.


By re-implementing Smalltalk’s ideas in C, Cox made it possible for Objective-C programmers to organize their program’s architecture using Smalltalk’s higher level abstractions while fine-tuning performance-critical code in procedural C, which meant that Objective-C programs could run just as fast as traditional C programs. Moreover, because they did not need to be installed alongside a Smalltalk virtual machine, their memory footprint was comparable to that of C programs, and, being fully native to the platform, would look and feel the same as all other applications on the system.

Wooster quotes a section on the development of NeXT’s additions to Objective-C: categories, protocols, forwarding, and more.

Previously: The Appsmiths.

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