evans@mhuxt.UUCP (crandall) (06/22/85)
A few weeks ago someone from the U of Utah posted a note that they would be offering their PSL for the Mac for a $75 licensing/distribution fee. I sent for the appropriate legal form, filled it out, and was amazed to get a package from Utah in about 5 working days. The package includes two disks - one for 128k Macs, the other for the 512k machines. Both disks contain some sample programs, a public domain text editor, a system folder, PSL, and a series of PSL lessons. The main difference between the two versions is the size of programs you can run - the 128k version allows only 100 new symbols and 1200 items, while the 512k version is good for 1000 symbols and 45000 items. Clicking on PSL brings up two windows - input and output. You type into the input window and select "evaluate", "stuff region", or "evaluate all" to evaluate a single line, a selected region, or the entire input window respectively. Alternatively you can type directly into the output window where characters are processed by the PSL reader as they are typed - this mode is somewhat useless as editing keys (backspace for example) don't function. In the input window mode there is limited paranthesis matching (the system beeps if you have an extra right paren.). I have never played with the PSL dialect before, but going through the documentation and some of the lessons was enough to get a reasonable feel for it. The package seems to work pretty well - it is certainly less buggy than ExperLisp at this point. As an experiment my wife (who has never programmed a computer) will be learning Lisp using PSL and Touretzky. PSL is small enough that you could learn Lisp with a single drive 128k Mac - something that would not be possible with Experlisp. The $75 price is also better than the $495 for ExperLisp. ExperLisp claims that there will be considerable improvements in their 2.0 version (if it has what they claim it will have, the package will be a bargain for $495), but Utah is working on a compiler and toolbox access for PSL (I forgot to mention - no graphics with PSL) as well as a subset of REDUCE. I have no idea if the $75 licensing fee entitles you to the future upgrades, but recommend PSL as a teaching tool worth the $75. Steve Crandall ihnp4!mhuxt!evans The views above are mine and not those of my employeer or my ferrets.