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require proof of the presence of synclos before stripping them with quote (issue #464)

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Alex Shinn 2018-04-01 21:38:21 +09:00
parent f67f63d570
commit ecbaa9939a
1 changed files with 21 additions and 20 deletions
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37
eval.c
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@ -593,30 +593,29 @@ sexp sexp_syntactic_closure_expr_op (sexp ctx, sexp self, sexp_sint_t n, sexp x)
return (sexp_synclop(x) ? sexp_synclo_expr(x) : x);
}
#if SEXP_USE_READER_LABELS
static int sexp_cyclic_synclop(sexp x) {
static int sexp_contains_syntax_p_bound(sexp x, int depth) {
int i;
sexp ls1, ls2;
if (!sexp_pairp(x))
return 0;
for (ls1=x, ls2=sexp_id_name(sexp_cdr(ls1));
sexp_pairp(ls2) && sexp_pairp(sexp_id_name(sexp_cdr(ls2)));
ls1=sexp_id_name(sexp_cdr(ls1)),
ls2=sexp_id_name(sexp_cdr(sexp_id_name(sexp_cdr(ls2))))) {
if (ls1 == ls2 || ls1 == sexp_id_name(sexp_car(ls2)))
if (sexp_synclop(x))
return 1;
if (depth <= 0)
return 0;
if (sexp_pairp(x)) {
for (i=0, ls1=x, ls2=x; sexp_pairp(ls1); ls1=sexp_cdr(ls1), ls2=(i++ & 1 ? sexp_cdr(ls2) : ls2)) {
if (sexp_contains_syntax_p_bound(sexp_car(ls1), depth-1))
return 1;
if (i > 0 && (ls1 == ls2 || ls1 == sexp_car(ls2)))
return 0; /* cycle, no synclo found, assume none */
}
for (ls1=x, ls2=sexp_id_name(sexp_car(ls1));
sexp_pairp(ls2) && sexp_pairp(sexp_id_name(sexp_car(ls2)));
ls1=sexp_id_name(sexp_car(ls1)),
ls2=sexp_id_name(sexp_car(sexp_id_name(sexp_car(ls2))))) {
if (ls1 == ls2 || ls1 == sexp_id_name(sexp_cdr(ls2)))
if (sexp_synclop(ls1))
return sexp_contains_syntax_p_bound(sexp_id_name(ls1), depth-1);
} else if (sexp_vectorp(x)) {
for (i = 0; i < sexp_vector_length(x); ++i)
if (sexp_contains_syntax_p_bound(sexp_vector_ref(x, sexp_make_fixnum(i)), depth-1))
return 1;
}
return 0;
}
#else
#define sexp_cyclic_synclop(x) 0
#endif
sexp sexp_strip_synclos_bound (sexp ctx, sexp x, int depth) {
int i;
@ -624,7 +623,7 @@ sexp sexp_strip_synclos_bound (sexp ctx, sexp x, int depth) {
if (depth <= 0) return x;
sexp_gc_preserve3(ctx, res, kar, kdr);
x = sexp_id_name(x);
if (sexp_pairp(x) && !sexp_cyclic_synclop(x)) {
if (sexp_pairp(x)) {
kar = sexp_strip_synclos_bound(ctx, sexp_car(x), depth-1);
kdr = sexp_strip_synclos_bound(ctx, sexp_cdr(x), depth-1);
res = sexp_cons(ctx, kar, kdr);
@ -641,6 +640,8 @@ sexp sexp_strip_synclos_bound (sexp ctx, sexp x, int depth) {
}
sexp sexp_strip_synclos (sexp ctx, sexp self, sexp_sint_t n, sexp x) {
if (!sexp_contains_syntax_p_bound(x, SEXP_STRIP_SYNCLOS_BOUND))
return x;
return sexp_strip_synclos_bound(ctx, x, SEXP_STRIP_SYNCLOS_BOUND);
}