(1) Are all fields essentially char arrays that
must be converted to the appropriate numeric
format -- much as is done with the lowly regarded
scanf() in c?
Fields that are displayed on forms, yes. Not database fields. They can be whatever you like within reason--a common problem for first-timers is that they think that pointers and what they point to are persistent when stored in a database record.
(2) How is numeric input with a decimal safely
handled? I note that fields may be limited to
numeric input but this does not preclude
alpha values beinig pasted onto the field
on a form.
Alpha values cannot be pasted into numeric fields as far as I know (I just tried it and it didn't work on at least one application--an admittedly limited test case).
(3) Must one use mathlib (either its source bound
into the app or calls to the library to do
floating point math?
You can also grow your own math functions. Ray Rischpater and I wrote a book called Advanced Palm Programming a few years ago that included a handful of basic trig functions (sin, cos, tan, asin, acos, atan, sqrt, etc.) that I developed out of a need to avoid Mathlib. You can probably find the book with CD-ROM used for under $10 on amazon. (The book also includes some basic field handling code, including trivial stuff like how to include negative numbers on a numeric field). You can also use public domain source code, or strip out a subset of Mathlib.
Extending my anticipated answer of "YES" to #1 above, is the driving paradigm for databases as is done with the Address app -- or Kinnon's Librarian app -- that is, the enums and the packed records representing pointers or offsets to data? Or, is it permissable to put in a few hard that will *always* be in the record versus other information that may be there intermittently?
To me, there is no driving paradigm. The packing/unpacking approach is certainly popular, but you can basically do whatever you want. It's not uncommon to use fixed-length char fields if you don't have serious space/size constraints. Former Cobol programmers seem to like that approach--it's familiar.
-- Regards, Steve Mann --- steve-at-slorevo.com Available for Contract Work
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