Path: news.cs.au.dk!not-for-mail
From: Flemming Gram Christensen <gram@mjolner.dk>
Newsgroups: comp.lang.beta
Subject: Re: Function call?
Date: 31 May 2000 12:54:33 +0200
Organization: University of Aarhus, Department of Computer Science (DAIMI)
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Atle <trollet@skynet.be> writes:

> Hello, good helpers!
> 
> I got everything so far to go OK, but I am having trouble figuring out the 'function call' syntax.
> I am sure it is simpler than what I'm used to, and that is why I can't figure it out ...
> 
> Let struct person be the way it was, name, addr, tlf.
> 
OK:

Person:(# name,addr,tlf:^Text #);

> >From C
> 
> /*
> * Instantiate an object of type person.
> * The name will be filled in, the rest will be default
> * values (inherited?)
> * The C way is to either build up structs or 
> * pass in a subclass pointer
> */
> struct person *new_person(char* name)
> {
> 	struct person *prv; /* A dynamic reference? */
> 
> 	prv = malloc(sizeof(struct person)); /* Create a dynamic instance? */
> 	if ( ! prv)
> 	{
> 		perror("malloc");
> 		return(0); /* Spoiled with automatic casting, should be (struct person*) 0 */
> 	}
> 
> 	strcpy(prv->name, name); /* Person has this name from input parm */
> 	strcpy(prv->addr, sc->addr); /* Don't bother with this now */
> 	strcpy(prv->tlf, "000"); /* Call the police */
> 
> 	return(prv); /* Imperative :-) that I understand enter and exit */
> }

in BETA:
new_person:
(# name:^text;
   p:^Person;
enter name[]     (* this is the parameter *)
do &person[]->p[];
   name.copy->p.name[];  (* copy name into p.name *)
   ''->p.addr[];         (* empty addr *)
   '112'->p.tlf[];       (* call police in EU *)
exit p[]
#);



> 
> void person_set(struct person *p, char *name, char *addr, char* tlf)
> {
> 	if (name)
> 		strcpy(p->name, name);
> 	
> 	if (addr)
> 		strcpy(p->addr, addr);
> 
> 	if (tlf)
> 		strcpy(p->tlf, tlf);
> }

person_set:
(# name,addr,tlf:^text;
   p:^Person;
enter (p[],name[],addr[],tlf[])
do (if name[]<>none then name.copy->p.name[] if);
   (if addr[]<>none then addr.copy->p.addr[] if);
   (if tlf[]<>none then tlf.copy->p.tlf[] if);
#);

> 
> int not_person_related(char *s)
> {
> 	s[0] = 'X';
> 	return(12);
> }

not_person_related:
(# s:^text;
enter s[];
do ('X',1)->s.inxPut  (* count from 1 *);
exit 12
#);


> 
> void main(int ac, char *av[])
> {
> 	struct person *p;
> 	int x, y;
> 	char s[25];
> 
> 	p = person_new("Newman");
> 	if ( ! p)
> 		exit(0);
> 
> 	person_set(p, 0, "Hovden", "3716 8532");
> /*-------- So far, so good. These are typically 'object' functions ---*/
> 
> 
> /* But what with this?	*/
> 
> 	x = not_person_related(s);
> 	x = not_person_related(p->tlf);		
> }

--program:descriptor--
(#
  p:^Person;
  x,y:@integer;
  s:@text;

do	
  'Newman'->person_new->p[];
  (p[],none,'hovden','3141 3123')->person_set;

  s[]->not_person_related->x;
  p.tlf[]->not_person_related->y;
#);

Regards.

-- 
/Flemming Gram Christensen

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