New functions: find-maxes and find-mins.

* eval.c (eval_init): New intrinsic functions find-maxes and
find-mins.

* lib.[ch] (find_maxes, find_mins): New function.

* tests/012/seq.tl: New tests.

* txr.1: Documented.

5 files changed, 86 insertions, 2 deletions

diff --git a/eval.c b/eval.c
index a55fdc60..e8d57ff0 100644
--- a/eval.c
+++ b/eval.c
@@ -7794,8 +7794,10 @@ void eval_init(void)
   reg_fun(intern(lit("find-if"), user_package), func_n3o(find_if, 2));
   reg_fun(intern(lit("rfind-if"), user_package), func_n3o(rfind_if, 2));
   reg_fun(intern(lit("find-max"), user_package), func_n3o(find_max, 1));
+  reg_fun(intern(lit("find-maxes"), user_package), func_n3o(find_maxes, 1));
   reg_fun(intern(lit("find-max-key"), user_package), func_n3o(find_max_key, 1));
   reg_fun(intern(lit("find-min"), user_package), func_n3o(find_min, 1));
+  reg_fun(intern(lit("find-mins"), user_package), func_n3o(find_mins, 1));
   reg_fun(intern(lit("find-min-key"), user_package), func_n3o(find_min_key, 1));
   reg_fun(intern(lit("find-true"), user_package), func_n3o(find_true, 2));
   reg_fun(intern(lit("multi-sort"), user_package), func_n3o(multi_sort, 2));
diff --git a/lib.c b/lib.c
index 009e2596..15902fbc 100644
--- a/lib.c
+++ b/lib.c
@@ -12055,6 +12055,38 @@ val find_max(val seq, val testfun_in, val keyfun_in)
   return nil;
 }
 
+val find_maxes(val seq, val testfun_in, val keyfun_in)
+{
+  val self = lit("find-maxes");
+  val testfun = default_arg(testfun_in, greater_f);
+  val keyfun = default_arg(keyfun_in, identity_f);
+  seq_iter_t iter;
+  val elem;
+  seq_build_t build;
+
+  seq_iter_init(self, &iter, seq);
+  seq_build_init(self, &build, seq);
+
+  if (seq_get(&iter, &elem)) {
+    val maxkey = funcall1(keyfun, elem);
+
+    seq_add(&build, elem);
+
+    while (seq_get(&iter, &elem)) {
+      val key = funcall1(keyfun, elem);
+      if (funcall2(testfun, key, maxkey)) {
+        maxkey = key;
+        seq_build_init(self, &build, seq);
+        seq_add(&build, elem);
+      } else if (!funcall2(testfun, maxkey, key)) {
+        seq_add(&build, elem);
+      }
+    }
+  }
+
+  return seq_finish(&build);
+}
+
 val find_max_key(val seq, val testfun_in, val keyfun_in)
 {
   val self = lit("find-max-key");
@@ -12085,6 +12117,11 @@ val find_min(val seq, val testfun, val keyfun)
   return find_max(seq, default_arg(testfun, less_f), keyfun);
 }
 
+val find_mins(val seq, val testfun, val keyfun)
+{
+  return find_maxes(seq, default_arg(testfun, less_f), keyfun);
+}
+
 val find_min_key(val seq, val testfun, val keyfun)
 {
   return find_max_key(seq, default_arg(testfun, less_f), keyfun);
diff --git a/lib.h b/lib.h
index 5cb52990..5bc180df 100644
--- a/lib.h
+++ b/lib.h
@@ -1400,8 +1400,10 @@ val rfind(val list, val key, val testfun, val keyfun);
 val find_if(val pred, val list, val key);
 val rfind_if(val pred, val list, val key);
 val find_max(val seq, val testfun, val keyfun);
+val find_maxes(val seq, val testfun_in, val keyfun_in);
 val find_max_key(val seq, val testfun, val keyfun);
 val find_min(val seq, val testfun, val keyfun);
+val find_mins(val seq, val testfun, val keyfun);
 val find_min_key(val seq, val testfun, val keyfun);
 val find_true(val pred, val list, val keyfun);
 val posqual(val obj, val list);
diff --git a/tests/012/seq.tl b/tests/012/seq.tl
index 45cf2b67..171ad300 100644
--- a/tests/012/seq.tl
+++ b/tests/012/seq.tl
@@ -464,6 +464,28 @@
   [find-max-key '("alpha" "charlie" "aardvark" "bravo") less upcase-str] "AARDVARK"
   [find-max-key #H(() (a 1) (b 2) (c 3)) : cdr] 3)
 
+(mtest
+  (find-maxes nil) nil
+  (find-maxes '(1 1 1 1 1)) (1 1 1 1 1)
+  (find-maxes '(2 1 1 1 1)) (2)
+  (find-maxes '(2 1 1 1 2)) (2 2)
+  (find-maxes '(2 1 2 1 2)) (2 2 2))
+
+(mtest
+  (find-maxes #()) #()
+  (find-maxes '(1 1 1 1 1)) (1 1 1 1 1)
+  (find-maxes '(2 1 1 1 1)) (2)
+  (find-maxes '(2 1 1 1 2)) (2 2)
+  (find-maxes '(2 1 2 1 2)) (2 2 2))
+
+(mtest
+  (find-maxes "") ""
+  (find-maxes "abracadabra") "rr"
+  (find-mins "abracadabra") "aaaaa")
+
+(test
+  (find-mins -10..11 : [callf * pppred ppred]) (2 3))
+
 (defvarl fn (do and
               (chr-isdigit @1)
               (not (chr-isdigit @2))))
diff --git a/txr.1 b/txr.1
index 942d79c3..c47d5fc6 100644
--- a/txr.1
+++ b/txr.1
@@ -37729,6 +37729,27 @@ is the one that is reported. See the notes under
 .code pos-max
 regarding duplicate maxima.
 
+.coNP Functions @ find-maxes and @ find-mins
+.synb
+.mets (find-maxes < iterable >> [ testfun <> [ keyfun ]])
+.mets (find-mins < iterable >> [ testfun <> [ keyfun ]])
+.syne
+.desc
+The
+.code find-maxes
+and
+.code find-mins
+functions have the same argument conventions as, respectively,
+.code find-max
+and
+.codn find-min .
+These functions differ in that they return a sequence of all the elements of
+.meta iterable
+which maximize the value of
+.metn keyfun .
+The returned sequence is of the same kind as
+.metn iterable .
+
 .coNP Functions @ find-max-key and @ find-min-key
 .synb
 .mets (find-max-key < iterable [ testfun <> [ keyfun ]])
@@ -37736,9 +37757,9 @@ regarding duplicate maxima.
 .syne
 .desc
 The
-.code find-min-key
-and
 .code find-max-key
+and
+.code find-min-key
 functions have the same argument conventions as, respectively,
 .code find-max
 and