4.4BSD/usr/src/old/lisp/franz/fex1.c
#ifndef lint
static char *rcsid =
"$Header: fex1.c,v 1.5 85/03/24 11:03:51 sklower Exp $";
#endif
/* -[Sat Mar 5 19:50:28 1983 by layer]-
* fex1.c $Locker: $
* nlambda functions
*
* (c) copyright 1982, Regents of the University of California
*/
#include "global.h"
#include "frame.h"
/* Nprog ****************************************************************/
/* This first sets the local variables to nil while saving their old */
/* values on the name stack. Then, pointers to various things are */
/* saved as this function may be returned to by an "Ngo" or by a */
/* "Lreturn". At the end is the loop that cycles through the contents */
/* of the prog. */
lispval
Nprog() {
register lispval where, temp;
struct nament *savedbnp = bnp;
extern struct frame *errp;
pbuf pb;
extern int retval;
extern lispval lispretval;
if((np-lbot) < 1) chkarg(1,"prog");
/* shallow bind the local variables to nil */
if(lbot->val->d.car != nil)
{
for( where = lbot->val->d.car ; where != nil; where = where->d.cdr )
{
if(TYPE(where) != DTPR || TYPE(temp=where->d.car) != ATOM)
errorh1(Vermisc,
"Illegal local variable list in prog ",nil,FALSE,
1,where);
PUSHDOWN(temp,nil);
}
}
/* put a frame on the stack which can be 'return'ed to or 'go'ed to */
errp = Pushframe(F_PROG,nil,nil);
where = lbot->val->d.cdr; /* first thing in the prog body */
switch (retval) {
case C_RET: /*
* returning from this prog, value to return
* is in lispretval
*/
errp = Popframe();
popnames(savedbnp);
return(lispretval);
case C_GO: /*
* going to a certain label, label to go to in
* in lispretval
*/
where = (lbot->val)->d.cdr;
while ((TYPE(where) == DTPR)
&& (where->d.car != lispretval))
where = where->d.cdr;
if (where->d.car == lispretval) {
popnames(errp->svbnp);
break;
}
/* label not found in this prog, must
* go up to higher prog
*/
errp = Popframe(); /* go to next frame */
Inonlocalgo(C_GO,lispretval,nil);
/* NOT REACHED */
case C_INITIAL: break;
}
while (TYPE(where) == DTPR)
{
temp = where->d.car;
if((TYPE(temp))!=ATOM) eval(temp);
where = where->d.cdr;
}
if((where != nil) && (TYPE(where) != DTPR))
errorh1(Vermisc,"Illegal form in prog body ", nil,FALSE,0,where);
errp = Popframe();
popnames(savedbnp); /* pop off locals */
return(nil);
}
lispval globtag;
/*
Ncatch is now linked to the lisp symbol *catch , which has the form
(*catch tag form)
tag is evaluated and then the catch entry is set up.
then form is evaluated
finally the catch entry is removed.
*catch is still an nlambda since its arguments should not be evaluated
before this routine is called.
(catch form [tag]) is translated to (*catch 'tag form) by a macro.
*/
lispval
Ncatch()
{
register lispval tag;
pbuf pb;
Savestack(3); /* save stack pointers */
if((TYPE(lbot->val))!=DTPR) return(nil);
protect(tag = eval(lbot->val->d.car)); /* protect tag from gc */
errp = Pushframe(F_CATCH,tag,nil);
switch(retval) {
case C_THROW: /*
* value thrown is in lispretval
*/
break;
case C_INITIAL: /*
* calculate value of expression
*/
lispretval = eval(lbot->val->d.cdr->d.car);
}
errp = Popframe();
Restorestack();
return(lispretval);
}
/* (errset form [flag])
if present, flag determines if the error message will be printed
if an error reaches the errset.
if no error occurs, errset returns a list of one element, the
value returned from form.
if an error occurs, nil is usually returned although it could
be non nil if err threw a non nil value
*/
lispval Nerrset()
{
lispval temp,flag;
pbuf pb;
Savestack(0);
if(TYPE(lbot->val) != DTPR) return(nil); /* no form */
/* evaluate and save flag first */
flag = lbot->val->d.cdr;
if(TYPE(flag) == DTPR) flag = eval(flag->d.car);
else flag = tatom; /* if not present , assume t */
protect(flag);
errp = Pushframe(F_CATCH,Verall,flag);
switch(retval) {
case C_THROW: /*
* error thrown to this routine, value thrown is
* in lispretval
*/
break;
case C_INITIAL: /*
* normally just evaluate expression and listify it.
*/
temp = eval(lbot->val->d.car);
protect(temp);
(lispretval = newdot())->d.car = temp;
break;
}
errp = Popframe();
Restorestack();
return(lispretval);
}
/* this was changed from throw to *throw 21nov79
it is now a lambda and really should be called Lthrow
*/
lispval
Nthrow()
{
switch(np-lbot) {
case 0:
protect(nil);
case 1:
protect(nil);
case 2: break;
default:
argerr("throw");
}
Inonlocalgo(C_THROW,lbot->val,(lbot+1)->val);
/* NOT REACHED */
}
/* Ngo ******************************************************************/
/* First argument only is checked - and must be an atom or evaluate */
/* to one. */
lispval
Ngo()
{
register lispval temp;
chkarg(1,"go");
temp = (lbot->val)->d.car;
if (TYPE(temp) != ATOM)
{
temp = eval(temp);
while(TYPE(temp) != ATOM)
temp = errorh1(Vermisc,"Illegal tag to go to",nil,TRUE, 0,lbot->val);
}
Inonlocalgo(C_GO,temp,nil);
/* NOT REACHED */
}
/* Nreset ***************************************************************/
/* All arguments are ignored. This just returns-from-break to depth 0. */
lispval
Nreset()
{
Inonlocalgo(C_RESET,inewint(0),nil);
}
/* Nbreak ***************************************************************/
/* If first argument is not nil, this is evaluated and printed. Then */
/* error is called with the "breaking" message. */
lispval
Nbreak()
{
register lispval hold; register FILE *port;
port = okport(Vpoport->a.clb,stdout);
fprintf(port,"Breaking:");
if ((hold = lbot->val) != nil && ((hold = hold->d.car) != nil))
{
printr(hold,port);
}
putc('\n',port);
dmpport(port);
return(errorh(Verbrk,"",nil,TRUE,0));
}
/* Nexit ****************************************************************/
/* Just calls lispend with no message. */
Nexit()
{
lispend("");
}
/* Nsys *****************************************************************/
/* Just calls lispend with no message. */
lispval
Nsys()
{
lispend("");
}
lispval
Ndef() {
register lispval arglist, body, name, form;
form = lbot->val;
name = form->d.car;
body = form->d.cdr->d.car;
arglist = body->d.cdr->d.car;
if((TYPE(arglist))!=DTPR && arglist != nil)
error("Warning: defining function with nonlist of args",
TRUE);
name->a.fnbnd = body;
return(name);
}
lispval
Nquote()
{
return((lbot->val)->d.car);
}
lispval
Nsetq()
{ register lispval handy, where, value;
register int lefttype;
value = nil;
for(where = lbot->val; where != nil; where = handy->d.cdr) {
handy = where->d.cdr;
if((TYPE(handy))!=DTPR)
error("odd number of args to setq",FALSE);
if((lefttype=TYPE(where->d.car))==ATOM) {
if(where->d.car==nil)
error("Attempt to set nil",FALSE);
where->d.car->a.clb = value = eval(handy->d.car);
}else if(lefttype==VALUE)
where->d.car->l = value = eval(handy->d.car);
else errorh1(Vermisc,
"Can only setq atoms or values",nil,FALSE,0,
where->d.car);
}
return(value);
}
lispval
Ncond()
{
register lispval where, last;
where = lbot->val;
last = nil;
for(;;) {
if ((TYPE(where))!=DTPR)
break;
if ((TYPE(where->d.car))!=DTPR)
break;
if ((last=eval((where->d.car)->d.car)) != nil)
break;
where = where->d.cdr;
}
if ((TYPE(where)) != DTPR)
return(nil);
where = (where->d.car)->d.cdr;
while ((TYPE(where))==DTPR) {
last = eval(where->d.car);
where = where->d.cdr;
}
return(last);
}
lispval
Nand()
{
register lispval current, temp;
current = lbot->val;
temp = tatom;
while (current != nil)
if ( (temp = current->d.car)!=nil && (temp = eval(temp))!=nil)
current = current->d.cdr;
else {
current = nil;
temp = nil;
}
return(temp);
}
lispval
Nor()
{
register lispval current, temp;
current = lbot->val;
temp = nil;
while (current != nil)
if ( (temp = eval(current->d.car)) == nil)
current = current->d.cdr;
else
break;
return(temp);
}