Re: Has anyone hand-written a scanner/parser module?

Another example for the OP:


Back in the 80's I was a computer tech with MAI Basic Four, Inc.
(originally Basic Four Corp.) and in some spare time I wrote a PILOT
interpreter in Basic Four Business Basic.


The scanner, parser, and semantics were rather blurred together. (I
have old listings somewhere, but I don' really remember any of the
code details) The gist of the scanner used the string indexing
features of Busisness Basic. (Read a line, then scan along the string
with the indexes)


As John mentioned about the odd syntax of FORTRAN, PILOT syntax is
different. PILOT is supposedly a language that teachers who are not
programmers can use to write instructional and quiz type "programs".
The commands are one or two char long and end with a colon. My
scanner/parser would look for the colon and then backtrack to build
the command symbol.


At the time it was a fun exercise, but I soon got bored with it, as
PILOT is not a very useful language aside from presenting material to
students and testing their knowledge with limited logic.


Back in the 90's I wrote a completely different PILOT interpreter in
Visual Basic 3.0 for Windows, using the same find colon/backtrack
approach. I added my own PILOT extentions that would allow test
results to be logged for the instructor with the intent of producing
an automated testing system, but I never got it finished. (Our church
was just then setting up a computer lab for our school, and I had
thought to provide it to them).


Charles E. Bortle, Jr.

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