From mboxrd@z Thu Jan  1 00:00:00 1970
Date: Mon,  5 Sep 1994 01:01:49 -0400
From: Alberto Nava beto@plan9.cs.su.oz.au
Subject: a few questions about alef
Topicbox-Message-UUID: 0333ae86-eac8-11e9-9e20-41e7f4b1d025
Message-ID: <19940905050149.pEFhZUNcmo6jvTIyLzaV-ouuZo17Vv4Dk9ACODUk_-g@z>


I've been working with alef in the last weeks
and I have a few questions about it.

1) I had some problems with rescue. For example the
output of this programs is "2+" and not "21". If I name
the recues then the output is ok, 21.

#include <alef.h>

void
main(int argc, byte **argv)
{
	 rescue  {
		print("1");
		return;
	 }
	 rescue  {
		print("2");
		raise ;
	 } 
	 raise ;	
}

2) Do we have something like pointer to functions of an 
adt in alef. I would like to write something like this.

enum {TEXT, AUDIO, VIDEO, MULTI};

void (*f[]) = { /* I'm not sure about f or Mesg.f */
	[TEXT]  Mime.ldtext(),
	[AUDIO] Mime.ldaudio(),
	[VIDEO] Mime.ldvideo(),
	[MULTI] Mime.ldmulti(),
};

and later do (*f[type])(); /* this avoid switch or if else */


3) Some time in an adt I declared another unamed adt
  which has functions which common names. For example:

#include <alef.h>

adt Mime{
	.....
	void write(*Mime,int);
};

adt Mesg {
	.....
	Mime;
	void write(*Mesg,int);
};

If I want to access Mime.write through a Mesg object, Is it
save to use casting? 

void
Mesg.write(Mesg *m,int)

	((Mime *)m)->write(0); /* in order to call MIME.write */
}