
Convert for the PSION (v0.99) April 1997

What?

Convert is (as it's name suggests) a piece of software to
convert between units. It wil convert many types including
both imperial and metric. I think all the measurements I
have used are the British ones.

It's fairly clever in that it wil only convert between
units of a common type - ie, if you enter 15 kilograms,
it will not allow you to attempt to convert this to miles.

Why?

This is a small program which I wrote to experiment with
reading .DBF files in OPL. Along the way, I discovered
dialogs. I have included the source code, which I imagine
will be of interest to experienced/inexperienced programmers
attempting to learn OPL.

How?

The program was written in the 3a emulator on a PC and used
successfully on a 3c. It is not guaranteed to run on these
or any other platform! (But it probably will.)

Installation

Copy CONVERT.DBF to your local \DAT\ directory
Copy CONVERT.OPO either to your \OPO\ directory or your
\APP\ directory
(If you copy it to \OPO\ it can be run from the RunOPL
application, otherwise, it may be necessary to install it
in the system screen.)
If you are interested in the programming, install CONVERT.OPL
in your \OPL\ directory

Modification

The file CONVERT.DBF is visible as a "Data" (your Psion's
Database package) document. The file can be opened and
modified by this application. You can use the Data application
to add units to be converted to and from. All units in the
data file have a common type. For example included in each
record of the database file is a unit name, a common type and
a factor to convert the unit to the common type. If you desire
to add a type of unit, you must enter the factor which will
convert the unit to the common type. If you wished to add a
distance unit, you must know how to convert it to metres.

*** Please do not release any modified .DBF files.

Future development

The program was never intended for release and as such is very
un-functional. One of the major problems is that the types to
be converted from are held in a list which for dialog box
purposes must fit into a string. This means that the sum of
lengths of the names of each unit (plus one for each unit,
because they are separated by commas) must not exceed 255. It
is hoped that the next release (if there is one) will overcome
this limitation.

I hope to add a field to the database which holds an abbreviation
of the names of the units, but I haven't bothered, yet, since I
decided the above problem was more urgent.

Closing words

This release is yours to do what you please with. I only ask
<freeware author whinge mode on>
that you do not redistribute the program with a modified .DBF
file and that you EMail me if you download / use it - I only
want to know how far it's spread.
<freeware author whinge mode off>

Ken McMullan - kd.mcmullan@ulst.ac.uk

Enjoy.
