ffi: handle sub operation in carray.

Thus, [ca 3..5] syntax works for slice extraction.
However, this works referentially, not by making a copy.
The extracted subarray points to the original memory,
until carray-dup is invoked on it.

* ffi.c (carray_sub): New function.
(ffi_init): carray-sub intrinsic registered.

* ffi.h (carray_sub): Declared.

* lib.c (sub): Handle carray via carray_sub.

* txr.1: Documented changes in sub.

1 files changed, 2 insertions, 0 deletions

diff --git a/lib.c b/lib.c
index 6e14e618..4c345615 100644
--- a/lib.c
+++ b/lib.c
@@ -9179,6 +9179,8 @@ val sub(val seq, val from, val to)
   case NIL:
     return nil;
   case COBJ:
+    if (seq->co.cls == carray_s)
+      return carray_sub(seq, from, to);
     seq = nullify(seq);
     /* fallthrough */
   case CONS: