View source for Prog Section 5

=Mobile Memory and PC Data Fields=

 <i>"We all have nightmares to remind ourselves who we really are."</i>
    -- Leonard Shelby, Memento

: One of the most prominently lacking features from the original prog specification was 
: the ability for mobileâ€™s to have a notion of "memory", or the total lack of any internal
: state (other than â€˜fightingâ€™ or â€˜not fightingâ€™).

: For example, mobiles could do none of the following:
:  - Remember which pcâ€™s had been tasked with a quest 
:  - Remember pcâ€™s who have attacked them in the past 
:  - Have a dialogue with a pc, where the mobile remembers what has been said 
:  - Marking a pc to be attacked by all the mobs in a given town or location 
:  - Marking a pc to get lower prices/preferred treatment from various mobs 

: Given the dearth of these features, we have implemented several different solutions for 
: these problems. 

=MOBILE MEMORY=

==Integer Memory==
:   Firstly, every instance of a mobile has ten integer values associated with it. These
:   values, or "slots" as they are referred to, are themselves number from 0 to 9. From 
:   within a prog, these values can be set to specific values, incremented, decremented, 
:   and then tested by the mobile to see if they are equal to, not equal to, greater than, 
:   or less than a specific value.
   
:   To see why this might be useful, consider a hen, which can be "fed" grain. Every time 
:   the hen is fed, it would increment its "0" slot. If the "0" slot is greater than 10 (it
:   has been fed ten times), it refuses to eat, being too full. Then, over time (via a rand_prog,
:   say), the hen gradually becomes less full, until itâ€™s ready to eat again. 

:   The following are the mpcommands and if checks associated with mobile integer memory:
:     mpvalueup
:     mpvaluedown
:     mpvalueset
:     mpvaluerand
:     if mobvalue(<slot #>)

:   In addition to these, the value of a slot can be referenced by a variable, given by $0, $1, ... $9,
:   where the number corresponds to the given slot number. 
   
:   Thus, if $0 had a value of "3", and $0 appeared in a prog, $0 would be interpreted as "3" wherever
:   it occurred. [Note: For technical reasons, the $# variables can never appear on the left hand 
:   side of any if check (i.e., before the operator)]. 

==Character Memory==
:   After implementing integer memory for mobiles, we discovered that while useful, it was not yet
:   complete enough to allow for things we had planned. So, mobiles were given character memory,   
:   in the form of focus fields. 

:   Essentially, the focus fields allow the mobile to store PC information. Mobiles have two focus 
:   fields, though they may have more in the future. Mobiles store their focus in the $f variable. 

:     $f0 references the first focus slot.
:     $f1 references the second focus slot.

:   The following mpcommands govern the focus system:
:     mpfocus: Focuses on target player currently in the game, with specified focus slot
:     mpunfocus: Unfocuses the specified slot.

==Memory==
:   In addition to the ability to focus on individual pcâ€™s, a mobile can also "remember" 
:   a pc. Essentially, this is a binary toggle that every mobile has. Given a specific pc, 
:   a mobile either does, or does not "remember" that pc. This memory persists until the mobile
:   "forgets" the player, or until the mobile perishes.

:   The following mpcommands govern the remembrance system:
:     mpremember: Remembers target player 
:     mpunremember: Forget target player if remembers: True if mobile remembers target player 

==Personal PC Value Fields==
:   If a mobile has "remember"-ed a pc, they gain a single integer field which they associate
:   with a pc. This operates exactly as the mobile integer memory fields, except that a different 
:   set of commands reference this value, it is associated only with a specific remembered PC,
:   and (most importantly), it is relative to that particular mob. This means, for example, that
:   a hen could remember a pc, and set their personal value to 3, while an ethron could remember
:   them, set their personal value to 5, and both of them would "see" the PC as having their own,
:   personal value. 

:   The following mpcommands govern the personal pc value fields:
:     mpmemvset: Sets a value on target player 
:     mpmemvup: Increase a playerâ€™s value by one 
:     mpmemvdown: Decrease a playerâ€™s value by two 
:     if mobvcheck: Checks a playerâ€™s personal value field 
    
  
       
=PC DATA=

:  Every player has 65,535 binary values associated with their player file. These values can be
:  toggled or checked by progs, and are permanent, until altered by a mobile or an affect. 

:  By no coincidence, there is a one to one correspondence between vnums and these binary bits. 
:  In general, a builder should only be altering bits which correspond to vnums in his or her area.

:  The following are commands which can set bits:
:    mpbitset: Sets a bit to 0 or 1
:    mpaddaff (using toggleoffaff or toggleonaff to toggle the bit after a specified duration)
:    if isbitset: True if the specified bit is set to 1 

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