PEEKEXISTS variable-name = axmud-object-property, expression
PEEKEXISTS ARRAY variable-name = axmud-object-property, expression

   Synopsis:
      Checks an Axmud internal hash property for a key matching the expression

   Notes:
      PEEK gives Axbasic scripts access to most of Axmud's internal data (see 
         the help for the PEEK statement for a full explanation).
      PEEKEXISTS can only be used with hash properties such as 
         "world.current.currencyHash". It cannot be used with a scalar property
         such as "world.current.name", a list property such as  
         "world.current.doorPatternList" or a Perl object such as 
         "world.current".
      Hashes are a collection of key-value pairs, with each key being unique in 
         the hash. (Some languages use the term 'associative array' instead.)
      PEEKEXISTS searches the hash for a key that matches the value of the
         expression and sets 'variable-name' accordingly. If the key is found, a
         string variable is set to "true" and a numeric variable is set to 1. If 
         the key is not found, a string variable is set to "undef" and a numeric 
         variable is set to "false".

   Examples:
      ! Look for the key "gold", and store the result ("true" or "false") in an
      ! Axbasic global string variable
      PEEKEXISTS result$ = "world.current.currencyHash", "gold"

      ! Look for the key "gold", and store the result (1 or 0) in an Axbasic
      ! global numeric variable
      PEEKEXISTS result = "world.current.currencyHash", "gold"

      ! Look for the key "gold", and store the result ("true" or "false") in an
      ! Axbasic global string array
      PEEKEXISTS ARRAY result$ = "world.current.currencyHash", "gold"

      ! Look for the key "gold", and store the result ("true" or "false") in an
      ! Axbasic local string variable
      LOCAL result$
      PEEKEXISTS result$ = "world.current.currencyHash", "gold"
