[plt-scheme] ATTN: Neil Van Dyke (and some philosophical musings on debuggers)

From: Eric M. Kidd (Eric.M.Kidd at Dartmouth.EDU)
Date: Wed Sep 15 13:37:46 EDT 2004

I'm trying to get in touch with Neil Van Dyke.  Shriram Krishnamurthi suggested I post directly to the PLT list.  If you're reading, please drop me line, or check for my earlier e-mails in your spam folders.

My humble apologies for abusing the list.

Obligatory Scheme:

The more I deal with novice programmers (people who will never get a CS degree, but who need to do a little scripting), the more I realize they want two things:

1. Really good error messages.

2. A truly excellent debugger.  The need for a good debugger is inversely proportional to the ease of debugging with 'display' or 'printf' statements.

Scheme offers the possibility of (1) and (2), thanks to macro hygenie.  LISP-style macros are pretty much impossible to support well in a debugger.

Basically, scriptors seem to have a fairly weak grasp of what their program is doing.  They form erroneous theories about what their code should do, they can't "execute" it as reliably in their heads, and they're not going to reason about it as much as they should.  Perhaps in a formal educational environment these problems can be cured through instruction.  But debuggers do seem to help scriptors visualize their program's execution.

On the flip side, do debuggers make programmers sloppy?  I know lots of Scheme and LISP people who think so, and Linus Torvalds seems to agree.


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