🚀 go-pugleaf

cz@ecn.net.au wrote:

> I am wondering if it is possible, in m2, to have a procedure that can
>be called with an un-defined number of parameters, with un-defined
>types (defined ofcourse when the proc is called)... i.e for use with
>porting the printf() function in C over to modula-2...

It's not possible in the 'standard' language. Some implementations provide
extensions to the languages (XDS) or can be deceived using pragmae and code
procedures (TopSpeed).

Here's an XDS example:

<*+ m2extensions *>                -- turn language extensions ON
DEFINITION MODULE FormStr;

IMPORT  SYSTEM;

PROCEDURE print (VAR str: ARRAY OF CHAR;   -- This procedure works like ANSI C 
                     fmt: ARRAY OF CHAR;   -- sprintf function
                 SEQ arg: SYSTEM.BYTE);


In TopSpeed, you should write:

(*# save, call(var_arg => on, c_conv => on) *)
(*# call(reg_param => (), o_a_copy => off)  *)

PROCEDURE print(VAR str: ARRAY OF CHAR;
                    fmt: ARRAY OF CHAR);

(*# restore *)

and do some tricks in the implementation.

======================================================================
Dmitry V. Leskov                      Institute of Informatics Systems
Programmer                                         Novosibirsk, Russia

snowman@iis.nsk.su