Re: program design language - a reality?

[dws]

To put a bit of historical context around this: In 1975 there weren't many viable display options. Personal graphic workstations were science fiction. This was five years before the then forward-thinking "3M" initiative, where "3M" referred to a machine with 1 Mb of disk, 1 megahertz of processor, and a megapixel (1024 by 1024 by 1 bit) display. Sounds silly now, but this was before the Apple ][, the IBM PC, or the first Mac. In that context, it's not surprising PDL was text-based. Research in graphics design techniques hadn't advanced very far beyond what could be done by pen/pencil and plotter.

Roll the clock forward two and a half decades. Laptops with 1024 x 840 flat-panel graphics are a commodity, years of methodology wars have reached a momentary truce that's given us UML, and drawing tools like Visio have templates that support it. Getting hardcopy takes a few seconds (or minute, if you have to warm your laser printer up), and costs a few pennies per page.

Meanwhile, on the software front, languages have evolved that let us specify class structures and interfaces separate from implementation. And people have decided that reviewing these isn't such a bad thing after all.

PDL was overtaken by technology. Pseudo code remains a viable design technique to be applied now and then, but it's more often than not used as footnotes on UML diagrams.