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backq.c
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C/C++ Source or Header
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1987-06-04
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6KB
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383 lines
/*
(c) Copyright Taiichi Yuasa and Masami Hagiya, 1984. All rights reserved.
Copying of this file is authorized to users who have executed the true and
proper "License Agreement for Kyoto Common LISP" with SIGLISP.
*/
#include "include.h"
#define attach(x) (vs_head = make_cons(x, vs_head))
#define make_list (vs_push(Cnil), stack_cons(), stack_cons())
#define QUOTE 1
#define EVAL 2
#define LIST 3
#define LISTA 4
#define APPEND 5
#define NCONC 6
object siScomma;
object siScomma_at;
object siScomma_dot;
object Slist;
object SlistA;
object Sappend;
object Snconc;
object Sapply;
object Svector;
kwote_cdr()
{
object x;
x = vs_head;
if (type_of(x) == t_symbol) {
if ((enum stype)x->s.s_stype == stp_constant &&
x->s.s_dbind == x)
return;
goto KWOTE;
} else if (type_of(x) == t_cons || type_of(x) == t_vector)
goto KWOTE;
return;
KWOTE:
vs_head = make_cons(vs_head, Cnil);
vs_head = make_cons(Squote, vs_head);
}
kwote_car()
{
object x;
x = vs_top[-2];
if (type_of(x) == t_symbol) {
if ((enum stype)x->s.s_stype == stp_constant &&
x->s.s_dbind == x)
return;
goto KWOTE;
} else if (type_of(x) == t_cons || type_of(x) == t_vector)
goto KWOTE;
return;
KWOTE:
vs_top[-2] = make_cons(vs_top[-2], Cnil);
vs_top[-2] = make_cons(Squote, vs_top[-2]);
}
/*
Backq_cdr(x) pushes a form on vs and returns one of
QUOTE the form should be quoted
EVAL the form should be evaluated
LIST the form should be applied to LIST
LISTA the form should be applied to LIST*
APPEND the form should be applied to APPEND
NCONC the form should be applied to NCONC
*/
int
backq_cdr(x)
object x;
{
int a, d;
cs_check(x);
if (type_of(x) != t_cons) {
vs_push(x);
return(QUOTE);
}
if (x->c.c_car == siScomma) {
vs_push(x->c.c_cdr);
return(EVAL);
}
if (x->c.c_car == siScomma_at || x->c.c_car == siScomma_dot)
FEerror(",@ or ,. has appeared in an illegal position.", 0);
a = backq_car(x->c.c_car);
d = backq_cdr(x->c.c_cdr);
if (d == QUOTE)
switch (a) {
case QUOTE:
vs_pop;
vs_head = x;
return(QUOTE);
case EVAL:
if (vs_head == Cnil) {
stack_cons();
return(LIST);
}
if (type_of(vs_head) == t_cons &&
vs_head->c.c_cdr == Cnil) {
vs_head = vs_head->c.c_car;
kwote_cdr();
make_list;
return(LIST);
}
kwote_cdr();
make_list;
return(LISTA);
case APPEND:
if (vs_head == Cnil) {
vs_pop;
return(EVAL);
}
kwote_cdr();
make_list;
return(APPEND);
case NCONC:
if (vs_head == Cnil) {
vs_pop;
return(EVAL);
}
kwote_cdr();
make_list;
return(NCONC);
default:
error("backquote botch");
}
if (d == EVAL)
switch (a) {
case QUOTE:
kwote_car();
make_list;
return(LISTA);
case EVAL:
make_list;
return(LISTA);
case APPEND:
make_list;
return(APPEND);
case NCONC:
make_list;
return(NCONC);
default:
error("backquote botch");
}
if (a == d) {
stack_cons();
return(d);
}
switch (d) {
case LIST:
if (a == QUOTE) {
kwote_car();
stack_cons();
return(d);
}
if (a == EVAL) {
stack_cons();
return(d);
}
attach(Slist);
break;
case LISTA:
if (a == QUOTE) {
kwote_car();
stack_cons();
return(d);
}
if (a == EVAL) {
stack_cons();
return(d);
}
attach(SlistA);
break;
case APPEND:
attach(Sappend);
break;
case NCONC:
attach(Snconc);
break;
default:
error("backquote botch");
}
switch (a) {
case QUOTE:
kwote_car();
make_list;
return(LISTA);
case EVAL:
make_list;
return(LISTA);
case APPEND:
make_list;
return(APPEND);
case NCONC:
make_list;
return(NCONC);
default:
error("backquote botch");
}
}
/*
Backq_car(x) pushes a form on vs and returns one of
QUOTE the form should be quoted
EVAL the form should be evaluated
APPEND the form should be appended
into the outer form
NCONC the form should be nconc'ed
into the outer form
*/
int
backq_car(x)
object x;
{
int d;
cs_check(x);
if (type_of(x) != t_cons) {
vs_push(x);
return(QUOTE);
}
if (x->c.c_car == siScomma) {
vs_push(x->c.c_cdr);
return(EVAL);
}
if (x->c.c_car == siScomma_at) {
vs_push(x->c.c_cdr);
return(APPEND);
}
if (x->c.c_car == siScomma_dot) {
vs_push(x->c.c_cdr);
return(NCONC);
}
d = backq_cdr(x);
switch (d) {
case QUOTE:
return(QUOTE);
case EVAL:
return(EVAL);
case LIST:
attach(Slist);
break;
case LISTA:
attach(SlistA);
break;
case APPEND:
attach(Sappend);
break;
case NCONC:
attach(Snconc);
break;
default:
error("backquote botch");
}
return(EVAL);
}
object
backq(x)
object x;
{
int a;
a = backq_car(x);
if (a == APPEND || a == NCONC)
FEerror(",@ or ,. has appeared in an illegal position.", 0);
if (a == QUOTE)
kwote_cdr();
return(vs_pop);
}
Lcomma_reader()
{
object in, c;
check_arg(2);
vs_pop;
in = vs_base[0];
if (backq_level <= 0)
FEerror("A comma has appeared out of a backquote.", 0);
c = peek_char(FALSE, in);
if (c == code_char('@')) {
vs_push(siScomma_at);
read_char(in);
} else if (c == code_char('.')) {
vs_push(siScomma_dot);
read_char(in);
} else
vs_push(siScomma);
--backq_level;
vs_push(read_object(in));
backq_level++;
stack_cons();
vs_base[0] = vs_base[1];
vs_pop;
}
Lbackquote_reader()
{
object in;
check_arg(2);
vs_pop;
in = vs_base[0];
backq_level++;
vs_base[0] = read_object(in);
--backq_level;
vs_base[0] = backq(vs_base[0]);
}
#define make_cf(f) make_cfun((f), Cnil, Cnil, NULL, 0);
init_backq()
{
object r;
siScomma = make_si_ordinary(",");
enter_mark_origin(&siScomma);
siScomma_at = make_si_ordinary(",@");
enter_mark_origin(&siScomma_at);
siScomma_dot = make_si_ordinary(",.");
enter_mark_origin(&siScomma_dot);
Slist = make_ordinary("LIST");
enter_mark_origin(&Slist);
SlistA = make_ordinary("LIST*");
enter_mark_origin(&SlistA);
Sappend = make_ordinary("APPEND");
enter_mark_origin(&Sappend);
Snconc = make_ordinary("NCONC");
enter_mark_origin(&Snconc);
Sapply = make_ordinary("APPLY");
enter_mark_origin(&Sapply);
Svector = make_ordinary("VECTOR");
enter_mark_origin(&Svector);
r = standard_readtable;
r->rt.rt_self['`'].rte_chattrib = cat_terminating;
r->rt.rt_self['`'].rte_macro = make_cf(Lbackquote_reader);
r->rt.rt_self[','].rte_chattrib = cat_terminating;
r->rt.rt_self[','].rte_macro = make_cf(Lcomma_reader);
backq_level = 0;
}