  LOOKUP

  【1.0 build 15 追加】
   LOOKUP <assoc> TO <array> SIZE <variable>

   Type: statement

   Retrieves all indexnames created in an associative array. The results
   are stored in <array>. As it sometimes is unknown how many elements this
   resulting array will contain, the array should not be declared
   explicitly. Instead, LOOKUP will declare the result array dynamically.

   If LOOKUP is being used in a function or sub, then <array> will have a
   local scope. Else <array> will be visible globally, and can be accessed
   within all functions and subs.

   The total amount of elements created in this array is stored in
   <variable>. This variable can be declared explicitly using LOCAL or
   GLOBAL. Example:

   LOOKUP mortal TO men$ SIZE amount
   FOR x = 0 TO amount - 1
       PRINT men$[x]
   NEXT

