Using ARcalc
************

   The program can be started from Workbench or Shell. It looks like a
standard calculator, sitting on the Workbench screen, in which you
should recognise the display and the keyboard. To avoid confusion, the
word `keys' will be used to indicate the Amiga keyboard keys, while the
word `buttons' will be used to indicate the `ARcalc' keyboard keys.

   You can vary the font and font size used to display `ARcalc'. The
font used, as many other initial characteristic that we will see later,
is defined in a configuration file called `ARcalc.config' that would
have to resides in the same directory as the `ARcalc' program. If this
file is not present `ARcalc' uses the same font as Workbench. Starting
from Shell, you can specify an alternate font by typing:

   `ARcalc <font name> <Y dimension>'

   `ARcalc' will override the config file default, and will try to open
the specified font. The font chosen is used for the keyboard labels and
for the display, but not for the `ARcalc' menus. It is also possible to
change the font after the calculator has been started, using the `Set
font ...' item in the `Settings' submenu of the `Project' menu. (See
 ARcalc menus.)

   `ARcalc' boot can fail for a number of reasons (not enough memory,
font chosen too big, errors opening libraries..); if this happens the
user is informed with an appropriate error message.

   The main feature of `ARcalc' is the ability to type complex
expressions in the same way they are usually written. This can be done
using either the Amiga keyboard or the `ARcalc' keyboard. You can see
the expression you are typing at the top of the display; this is called
the "edit area". You can edit the expression using either the tipical
Amiga string gadget shortcuts or the special `ARcalc' editing buttons.

   To calculate the result of the given expression, you have only to
press the `RETURN' key, or to click the `=' button; the result will be
displayed on the right side of the bottom of the display. This is
called the "result area". `ARcalc' uses the result area also to show
you its messages about syntax or miscalculation errors.

   Note that if a syntax error is found in the typed expression, the
cursor of the edit area indicates where the error is, while if a
miscalculation occurs (e.g. a division by zero) the cursor position is
meaningless. For a complete list of the syntax/miscalculation errors,
see  ARcalc menus, of this manual.