HELP
====

Function
--------

**HELP** displays lines of text on HUNTER's screen when the HELP key is
pressed.

Syntax
------

| HELP line number
| HELP numeric expression

Examples
--------

::

   1010 REM THIS IS A PIECE OF HELP TEXT
   1020 REM INTENDED TO ASSIST THE OPERATOR
   1030 REM IN THE USE OF HUNTER
   1040 REM PLEASE PRESS HELP TO RETURN
   1050 REM TO PROGRAM
   10000 HELP 1010

Execution of line 10000 will cause the block of remarks to be used as
the HELP text.

HELP requires an argument which must be a valid line number. The
referenced line must be a REM statement. When the operator presses HELP,
text from the referenced REM is placed on the screen. Use of the cursor
up and cursor down keys causes scrolling through a contiguous block of
REM statements. The HELP text start may be changed by executing another
HELP statement.

Normally, the help key on the HUNTER keyboard is disabled. Execution of
HELP causes the HELP code to be loaded into the keyboard table,
therefore enabling the use of the key. Once the HELP statement has been
executed, it is not possible to disable the HELP function except for
deleting the HELP code in the keyboard map.

.. Note::

   On power up the help key will be again disabled and therefore
   it is necessary to execute the HELP statement within the program
   initialisation.

It is recommended that all the HELP text be written contiguously so that
the operator may scroll through all of it. Scrolling stops when any
non-REM line is encountered, so blocks of text can be easily partitioned
if required.

.. Note::

   HELP text cannot be displayed if HUNTER is in graphics mode and
   operation of the HELP key is ignored. It is then necessary to use
   Shift-PWR to turn off HUNTER.