PC Toledo

Código: Selecionar todos

###    NEW LANGUAGE STATEMENTS    ###
=====================================
1. FOR EACH
   Harbour support all xHarbour functionality and it offers also additional
   features which are not available in xHarbour.
   a) it allows to iterate more then one variable
         FOR EACH a, b, c IN aVal, cVal, hVal
            ? a, b, c
         NEXT
   b) it allows to set descending order by DESCEND flag, f.e.:
         FOR EACH a, v IN aVal, cVal DESCEND
            ? a, b
         NEXT
   c) it has native support for hashes:
         FOR EACH x IN { "ABC" => 123, "ASD" => 456, "ZXC" => 789 }
            ? x, "@", x:__enumKey()
         NEXT
   d) it allows to assign string items, f.e.:
         s := "abcdefghijk"
         FOR EACH c IN @s
            IF c $ "aei"
               c := UPPER( c )
            ENDIF
         NEXT
         ? s      // AbcdEfghIjk
   e) it gives OOP interface to control enumerator variables what
      is very important when more then one variable is iterated or
      when FOR EACH is called recursively, f.e.:
         hVal := { "ABC" => 123, "ASD" => 456, "ZXC" => 789 }
         FOR EACH x IN hVal
            ? x:__enumIndex(), ":", x:__enumKey(), "=>", x:__enumValue(), ;
              "=>", x:__enumBase()[ x:__enumKey() ]
         NEXT
   f) it gives very flexible OOP mechanism to overload FOR EACH behavior
      for user define objects adding to above enumerator methods also
      __enumStart(), __enumStop(), __enumSkip() methods what allows to
      implement many different enumeration algorithms depending on used
      data
   g) it does not have any hardcoded limitations for recursive calls
      (it's limited only by available memory and HVM stack size), f.e.:
         proc main()
            p( 0 )
         return
         proc p( n )
            local s := "a", x
            ? n
            if n < 1000
               for each x in s
                  p( n + 1 )
               next
            endif
         return
   In xHarbour there is function HB_ENUMINDEX() which is supported by
   Harbour in XHB library.