Re: array of strings in a function

[Craig Carey <research@ijs.co.nz>]

Functions with varying numbers of arguments are handled by Ada 95:
construct an array of pointers at the place the procedure is called:
   -----   
   with Text_IO;
   with Ada.Unchecked_Deallocation;
   
   procedure Main is
   
      type String_Ptr is access all String;
      type SPA is array (Positive range <>) of String_Ptr;
   
      procedure Deallocate is new Ada.Unchecked_Deallocation (
                  Object => String, Name => String_Ptr);
   
      function "+" (X : String) return String_Ptr is
      begin
         return new String'(X);
      end "+";
   
      procedure Varargs (U : SPA) is
         Tmp      : String_Ptr;
      begin
         Text_IO.Put ("Got : ");
         for K in U'Range loop
            Text_IO.Put ("""" & String (U (K).all) & """");
            if K /= U'Last then Text_IO.Put (", "); end if;
            Tmp := U (K);
            Deallocate (Tmp);    --  No memory leak
         end loop;
         Text_IO.Put_Line (".");
      end Varargs;
   
      G     : String := "Efgh";
   begin

      Varargs (SPA'(1 => +"Abc", 2 => +G, 3 => +"Last"));

   end Main
   -----

The output:

|   Got : "Abc", "Efgh", "Last".


Syntax errors are a problm when the heap is not used (a GNAT pointer to
a string is 64 bits and twice the size of a pointer to a record).



On Thu, 16 Oct 2003 06:40:26 GMT, tmoran@acm.org wrote:
...
>  But you can certainly have a set of subprograms with the same name
>but differing number of parameters:
...



At Wed, 15 Oct 2003 13:49:42 +0200, Antonio Mart�nez wrote:
   Subject: Re: array of strings in a function
     [from  comp.lang.ada-@-ada-france.org ]

>What I want to do is a procedure (sorry, not a function) to do something 
>like this:
>
>my_AND("Entrada_1", "P2", "Output");
>
>and with this argument, this function have to write this:
>
>
>entity my_AND is port(
>   Entrada_1 : in std_logic;
>   P2		: in std_logic;
>   Output	: out std:logic;
>);
>
>(This is VHDL code, very similar to Ada95).
>
> In general, I don't know the number of string arguments.
...

Is that a parser project?.

Adagoop and Ayacc are options:

  ftp://ftp.usafa.af.mil/pub/dfcs/carlisle/usafa/adagoop/index.html
  http://www.mysunrise.ch/users/gdm/gsoft.htm




--  Craig Carey