XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX PRTCT XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

        Protecting against overwriting by leftshift softkeys (HP49) 

As is known, pressing a leftshift softkey is the fastest method to overwrite a 
variable in the current directory. But you may have sensitive variables which
should be protected against unintensionally owerwriting them in this way (not
against overwriting by the Filer or by using the STO key since these actions 
need preparation and will unlikely be carried out unintensionally). 

You may protect those variables with PRTCT. It can be used directly, or still
better assign it to the VAR key (after putting a TakeOver on the name 'PRTCT' 
or its content). The list of files intended to be protected has to be stored
in the variable 'P' where P denotes here the *reversed P*, symbol number 182.
This symbol is rarely used elsewhere. PRTCT highlightens the variables from
'P' and prevents them from being unintensionally overwritten with a key press
on leftshift and the corresponding softkey. 'P' may be empty in which case no
variable is protected. The same holds if the variable 'P' doesn't exist in the
current directory. There may be different P-lists in different directories, in
other words, PRTCT works context-sensitive.
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Wolfgang Rautenberg, raut@math.fu-berlin.de  www.math.fu-berlin.de/usr/raut