#12 Better Error Messages When Working on SPAD Code

[Martin Baker]

I would like better error messages when using both interpreter and compiler. Also hide underlying Lisp nature of the program from users using interpreter and writing SPAD.

The error messages in the interpreter don't seem very helpful, for instance if I just type something in at random:

(1) -> a|b
  >> Error detected within library code:
  (1 . failed) cannot be coerced to mode (NonNegativeInteger)

• Why is this an error with the library code rather than user input?
• What has this got to do with a NonNegativeInteger?

Some error messages are even worse and expect user to understand the underlying Lisp nature of the program.

Error messages when writing code for SPAD are often different from the interpreter errors. These compiler errors can be even more difficult to find. Some errors, with the top level syntax, don't give any clue where the error might be in the whole code. Other errors display a whole chunk of lisp code.

It would be useful to have documentation with a list of all the possible errors and what might be done about them. I started to keep a list of the errors that I was getting, but soon gave up, see page here:
http://www.euclideanspace.com/maths/standards/program/spad/debug/

[Martin Baker]

Note for other readers:
These issues are not formally managed on sourceforge (or anywhere else). Informal discussion of this is on the mailing list here:
https://groups.google.com/forum/?hl=en#!topic/fricas-devel/KVkYiaaKXJU
However it is difficult to find things on a mailing list so I have put the replies here:
http://www.euclideanspace.com/maths/standards/program/fricas/wishlist/errors/