@@USAG SG
USAG.TXT File
V 1.0 07/06/93
(c) Hewlett-Packard Company, 1992.
Overview
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The USAG (usage) application enables you to review the
stack argument object type usage for any command built
into the HP 48 or any library command.
Installation
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Transfer the USAG file from your computer to the HP 48.
The |USAG| menu label will show up in your HP 48 VAR
menu.
Procedure
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1. Enter on stack level 1 a list containing a command
name.
2. Press the |USAG| menu key. The HP 48 displays a
screen with usage information for the command you
specified in step 1.
Example
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Assuming that you transferred the USAG program to your HP
48, that you entered a list containing the COS command in
level 1, and that you pressed |USAG| in the VAR menu,
here's the screen you get:
┌─────Command or function identifier
Command or
function ┌────────────────────────────┐
name───────│ COS (Funct.) δS │──Special
┌─│ #1 of 4 │ function
│ │ │ attributes
Argument──┘ │ │
type set │ │
number ┌─│1: Real Number │
│ ├────┬─┬────┬──┬─────┬──┬────┤
Argument──┘ │NEXT│ │PREV│ │PRINT│ │EXIT│──Menu labels
type set └────┴─┴────┴──┴─────┴──┴────┘
This screen first tells you that COS is a function (all
commands are either RPN commands or functions). Also,
following the "(Funct.)" in your display (indicated here
by "δS" ) there are three additional special function
attribute characters: (1) a down arrow, which indicates
the function has an inverse (for ISOL), (2) a derivative
symbol, which indicates the function has a derivative,
and (3) an integral symbol, which indicates that you can
integrate the function. These characters do not appear
when the displayed command does not have the
corresponding properties.
The second line of the screen, showing "#1 of 4," tells
you that there are four possible combinations of argument
types for COS, and that the first one is currently
displayed. Like COS, some commands have only a few
acceptable combinations of argument types; others may
have many more.
The next several lines of the USAG screen show the
argument types accepted by the command and their
corresponding stack levels. For COS you are first shown
that it can operate on a real number in level 1. COS
takes just one argument, but for commands that require
more, all the arguments are shown on their appropriate
stack levels. Argument names match specific HP 48 object
types. (The exceptions are "Any," which means that all
object types are acceptable; "Symbolic," which means that
the argument can be an algebraic, a global name, or a
local name; and "PICT".)
The menu keys at the bottom of the screen enable you to
cycle forward (|NEXT|) and backward (|PREV|) through the
argument type combinations. As you press |NEXT| and
|PREV|, the second line of the display is updated, for
instance, to "#2 of 4", then "#3 of 4", and so on. The
calculator beeps when you step past the last argument
type combination (back to the first), or step backwards
from first to last. When you want to exit the
application, press |EXIT| to return to the normal stack
display. (Pressing the [ON] key also exits the
application.)
The |PRINT| key prints all of the argument combinations
to the current printer port.
If you use USAG to check the usage of a command that
takes no arguments or has just one argument combination,
the USAG menu labels don't appear, and the display
disappears at the next keystroke.
USAG operation depends on a common structure shared by
most HP48 and library commands. If a command deviates
from the common structure, USAG displays may be
incomplete. For example, USAG applied to ->Q shows only
the single argument "Any", which is not very helpful. In
the great majority of cases, USAG will be accurate, but
you may need to refer to the Advanced User's Reference
Manual.
