sum-each, mul-each: handle no vars case.

* stdlib/arith-each.tl (sys:arith-each): If there are no vars,
then just reduce to the identity element value.
This is alreading happening fine for the each-prod family
of operators.

* tests/016/arith.tl: Test cases covering the no vars
and empty iteration identity element cases for sum-each and
mul-each, as well as the *-prod variants.

* txr.1: Document empty iteration and empty vars behavior
for arithmetic each operators as well as the each-prod
family.

1 files changed, 42 insertions, 0 deletions

diff --git a/tests/016/log.tl b/tests/016/log.tl
new file mode 100644
index 00000000..3dcd9056
--- /dev/null
+++ b/tests/016/log.tl
@@ -0,0 +1,42 @@
+(load "../common.tl")
+
+(mtest
+  (each-true ()) t
+  (each-true ((a ()))) t
+  (each-true ((a ())) nil) t
+  (each-true ((a '(1 2 3))) a) 3
+  (each-true ((a '(nil 2 3))) a) nil
+  (each-true ((a '(1 2 3)) (b '(4 5 6))) (< a b)) t
+  (each-true ((a '(1 2 3)) (b '(4 0 6))) (< a b)) nil)
+
+(mtest
+  (some-true ()) :error
+  (some-true ((a ()))) nil
+  (some-true ((a ())) nil) nil
+  (some-true ((a '(1 2 3))) a) 1
+  (some-true ((a '(nil 2 3))) a) 2
+  (some-true ((a '(nil nil nil))) a) nil
+  (some-true ((a '(1 2 3)) (b '(4 5 6))) (< a b)) t
+  (some-true ((a '(1 2 3)) (b '(4 0 6))) (< a b)) t
+  (some-true ((a '(1 2 3)) (b '(0 1 2))) (< a b)) nil)
+
+(mtest
+  (each-false ()) :error
+  (each-false ((a ()))) t
+  (each-false ((a ())) t) t
+  (each-false ((a '(1 2 3))) a) nil
+  (each-false ((a '(nil))) a) t
+  (each-false ((a '(nil nil))) a) t
+  (each-false ((a '(1 2 3)) (b '(4 5 6))) (> a b)) t
+  (each-false ((a '(1 2 3)) (b '(4 0 6))) (> a b)) nil)
+
+(mtest
+  (some-false ()) :error
+  (some-false ((a ()))) nil
+  (some-false ((a ())) nil) nil
+  (some-false ((a '(1 2 3))) a) nil
+  (some-false ((a '(nil 2 3))) a) t
+  (some-false ((a '(nil nil nil))) a) t
+  (some-false ((a '(1 2 3)) (b '(4 5 6))) (> a b)) t
+  (some-false ((a '(1 2 3)) (b '(4 0 6))) (> a b)) t
+  (some-false ((a '(1 2 3)) (b '(0 1 2))) (> a b)) nil)