"I have a mind like a steel... uh... thingy." Patrick Logan's weblog.

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Friday, February 02, 2007

PL/I

I saw this in the Programming Language News blog...

PL/I for GCC 0.0.14 has been released. It is a PL/I front-end for the GNU Compiler Collection.
I wonder who's using it for what. Which computers ran PL/I in the past? IBM had an implementation for mainframes. Maybe for other mid-range systems as well?

PL/I was the systems programming language for Data General's mini and supermini computers. That's where I used it. I understand this was not quite *all* of IBM's PL/I specification. The language is fairly large.

It is somewhat more attractive than COBOL from my limited experience with both languages. It was straightforwardly procedural and recursive, with a reasonable exception handling mechanism. I'm not sure why PL/I did not win out over COBOL, unless it was the shear momentum of COBOL before PL/I was ready.

Update

Doug Landauer adds some interesting history in the comments. I forgot about Gary Kildall and PL/M.

End

1 comment:

Anonymous said...

Gary Kildall wrote one or more PL/I (subset) compilers for micros (8080 and, later, 8086). Later, PL/M was a descendent -- a smaller, simpler language but with somewhat similar syntax -- heavily used at Digital Research on the Operating Systems that were CP/M's descendents. Search "Gary Kildall" "PL/I compiler" will yield pointers to start some research, if desired.

Seems to me that PL/I lost out to COBOL for many of the same reasons that Ada lost out to C++ fifteen to twenty years later. PL/I was seen as this huge, complex beast of a language, with everyone's favorite kitchen sink thrown in, while COBOL was already pervasive, a necessary evil. COBOL's complexities didn't seem to matter as much, because they were already familiar.

PL/I had some funky features that were seen as difficult to implement at the time -- "on conditions", an early form of exceptions; and arbitrary user-specified data/word-size precision, with a zillion rules about how differently-sized variables would combine.

(Historical note: Some of my first real programs were written in PL/I, and run on one or the other of the IBM-360/91's at UCLA, around 1968. Also, I worked at Digital Research from 1984 to 1986, the most amusing aspect of which was that they still considered themselves to be serious competition for Microsoft.)

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Portland, Oregon, United States
I'm usually writing from my favorite location on the planet, the pacific northwest of the u.s. I write for myself only and unless otherwise specified my posts here should not be taken as representing an official position of my employer. Contact me at my gee mail account, username patrickdlogan.