seqp: expand definition of sequences.

* lib.c (seqp): Use seq_info to classify the object
as a sequence.

* txr.1: Update description of seqp.

2 files changed, 18 insertions, 13 deletions

diff --git a/lib.c b/lib.c
index 746f0e72..95e7573c 100644
--- a/lib.c
+++ b/lib.c
@@ -1021,18 +1021,8 @@ val nullify(val seq)
 
 val seqp(val obj)
 {
-  switch (type(obj)) {
-  case NIL:
-  case CONS:
-  case LCONS:
-  case VEC:
-  case STR:
-  case LSTR:
-  case LIT:
-    return t;
-  default:
-    return nil;
-  }
+  seq_info_t si = seq_info(obj);
+  return tnil(si.kind != SEQ_NOTSEQ);
 }
 
 loc list_collect(loc ptail, val obj)
diff --git a/txr.1 b/txr.1
index a7df3a1f..7b640f76 100644
--- a/txr.1
+++ b/txr.1
@@ -27715,11 +27715,26 @@ if
 is a sequence, otherwise
 .codn nil .
 
-A sequence is defined as a list, vector or string. The object
+Lists, vectors and strings are sequences. The object
 .code nil
 denotes
 the empty list and so is a sequence.
 
+Objects of type
+.code buf
+and
+.code carray
+are sequences, as are hash tables.
+
+Structures which implement the
+.code length
+or
+.code car
+methods are considered sequences.
+
+No other objects are sequences. However, future revisions of
+the language may specify additional objects that are sequences.
+
 .coNP Functions @ length and @ len
 .synb
 .mets (length << object )