suffix functions: leading dot is not delimiter

* stream.c (short_suffix, long_suffix): Do not treat the
starting dot of the last componet as a suffix delimiter.

* tests/018/path.tl: Test cases edited to reflect
requirements change; new tests added.

* txr.1: Updated.

3 files changed, 37 insertions, 19 deletions

diff --git a/stream.c b/stream.c
index 1c965c8c..ecd30ba6 100644
--- a/stream.c
+++ b/stream.c
@@ -5040,7 +5040,7 @@ val short_suffix(val name, val alt_in)
   const wchar_t *dot = wcsrchr(str, '.');
   const wchar_t *sl = if3(dot, wcspbrk(dot + 1, psc), 0);
 
-  if (!dot || (sl && sl[1])) {
+  if (!dot || (sl && sl[1]) || dot == str || wcschr(psc, dot[-1])) {
     return default_null_arg(alt_in);
   } else {
     wchar_t *suff = chk_strdup(dot + 1);
@@ -5063,7 +5063,10 @@ val long_suffix(val name, val alt_in)
     while (dot && (sl = wcspbrk(dot, psc)) && sl[1])
       dot = wcschr(sl + 1, '.');
 
-    if (!dot || (sl && sl[1])) {
+    if (dot && (dot == str || wcschr(psc, dot[-1])))
+      dot = wcschr(dot + 1, '.');
+
+    if (!dot || dot == str) {
       return default_null_arg(alt_in);
     } else {
       wchar_t *suff = chk_strdup(dot + 1);
diff --git a/tests/018/path.tl b/tests/018/path.tl
index 3dcb5eb3..a00b9465 100644
--- a/tests/018/path.tl
+++ b/tests/018/path.tl
@@ -7,14 +7,15 @@
   (short-suffix "" 0) 0
   (short-suffix "a") nil
   (short-suffix "a" 0) 0
-  (short-suffix ".") ""
+  (short-suffix ".") nil
   (short-suffix "a.") ""
   (short-suffix "a.b.") ""
-  (short-suffix ".c") "c"
+  (short-suffix ".c") nil
   (short-suffix "a.c") "c"
   (short-suffix "a.b.c") "c"
   (short-suffix "foo.txt.gz") "gz"
-  (short-suffix ".gz") "gz")
+  (short-suffix "txt.gz") "gz"
+  (short-suffix ".gz") nil)
 
 (mtest
   (long-suffix 42) :error
@@ -23,24 +24,29 @@
   (long-suffix "" 0) 0
   (long-suffix "a") nil
   (long-suffix "a" 0) 0
-  (long-suffix ".") ""
+  (long-suffix ".") nil
   (long-suffix "a.") ""
   (long-suffix "a.b.") "b."
-  (long-suffix ".c") "c"
+  (long-suffix ".c") nil
   (long-suffix "a.c") "c"
   (long-suffix "a.b.c") "b.c"
   (long-suffix "foo.txt.gz") "txt.gz"
-  (long-suffix ".gz") "gz"
-  (long-suffix ".txt.gz") "txt.gz")
+  (long-suffix ".gz") nil
+  (long-suffix ".txt.gz") "gz"
+  (long-suffix "/.txt.gz") "gz"
+  (long-suffix "a/.txt.gz") "gz")
 
 (mtest
   (short-suffix "/") nil
   (short-suffix "a/") nil
-  (short-suffix ".a/") "a"
+  (short-suffix "/.") nil
+  (short-suffix "a/.") nil
+  (short-suffix ".a/") nil
   (short-suffix ".a/b") nil
+  (short-suffix ".a/c.b") "b"
   (short-suffix ".a/b/") nil
-  (short-suffix ".a/b/.b") "b"
-  (short-suffix ".a/b/.b/") "b"
+  (short-suffix ".a/b/.b") nil
+  (short-suffix ".a/b/.b/") nil
   (short-suffix ".a/b/c.b") "b"
   (short-suffix ".a/b/c.b/") "b"
   (short-suffix ".a/b/c.b//") nil)
@@ -48,13 +54,17 @@
 (mtest
   (long-suffix "/") nil
   (long-suffix "a/") nil
-  (long-suffix ".a/") "a"
+  (long-suffix "/.") nil
+  (long-suffix "a/.") nil
+  (long-suffix ".a/") nil
   (long-suffix ".a/b") nil
   (long-suffix ".a/b/") nil
-  (long-suffix ".a/b/.b") "b"
-  (long-suffix ".a/b/.b/") "b"
+  (long-suffix ".a/b/.b") nil
+  (long-suffix ".a/b/.b/") nil
   (long-suffix ".a/b/c.b") "b"
   (long-suffix ".a/b/c.b/") "b"
   (long-suffix "a.b/c.d.e") "d.e"
   (long-suffix "a.b/c.d.e/") "d.e"
+  (long-suffix "a.b/c.d.e/f") nil
+  (long-suffix "a.b/c.d.e/f.g.h") "g.h"
   (long-suffix "a.b/c.d.e//") nil)
diff --git a/txr.1 b/txr.1
index 97def4e5..ba96ae34 100644
--- a/txr.1
+++ b/txr.1
@@ -57196,7 +57196,8 @@ What it means for
 to have a suffix delimiter is that the
 .code .
 character occurs somewhere in the last component of
-.metn path .
+.metn path ,
+other than as the character of that component.
 What constitutes the last component is specified
 in more detail below.
 
@@ -57236,8 +57237,10 @@ extracted from this last component.
 
 .verb
   (short-suffix "") -> nil
-  (short-suffix ".") -> ""
+  (short-suffix ".") -> nil
   (short-suffix "abc") -> nil
+  (short-suffix ".abc") -> nil
+  (short-suffix "/.abc") -> nil
   (short-suffix "abc" "") -> ""
   (short-suffix "abc.") -> ""
   (short-suffix "abc.tar") -> "tar"
@@ -57247,10 +57250,12 @@ extracted from this last component.
   (short-suffix "x.y.z/abc.tar.gz//") -> nil
 
   (long-suffix "") -> nil
-  (long-suffix ".") -> ""
+  (long-suffix ".") -> nil
   (long-suffix "abc") -> nil
+  (long-suffix ".abc") -> nil
+  (long-suffix "/.abc") -> nil
   (long-suffix "abc.") -> ""
-  (long-suffix "abc.tar") -> "txt"
+  (long-suffix "abc.tar") -> "tar"
   (long-suffix "abc.tar.gz") -> "tar.gz"
   (long-suffix "abc.tar.gz/") -> "tar.gz"
   (long-suffix "x.y.z/abc.tar.gz/") -> "tar.gz"