New: callable integers and ranges.

* lib.c (do_generic_funcall): Allow integers and ranges
to be function callable. They take one argument and
index into it or extract a slice. In the case of ranges,
this is a breaking change. Ranges can already be used
in the function position in some limited ways that are
not worth preserving.

* tests/012/callable.tl: New file.

* tests/012/iter.tl: Here we fix two instances of
breakage. Using txr -C 288 will restore the
behaviors previously tested here.

* txr.1: Documented.

1 files changed, 23 insertions, 0 deletions

diff --git a/tests/012/callable.tl b/tests/012/callable.tl
new file mode 100644
index 00000000..0f0e9327
--- /dev/null
+++ b/tests/012/callable.tl
@@ -0,0 +1,23 @@
+(load "../common")
+
+(mtest
+  [0 '(1 2 3)] 1
+  [1 '(1 2 3)] 2
+  [2 '(1 2 3)] 3)
+
+(mtest
+  [0 "abc"] #\a
+  [1 "abc"] #\b
+  [2 "abc"] #\c)
+
+(mtest
+  [0..1 '(1 2 3)] (1)
+  [1..3 '(1 2 3)] (2 3))
+
+(mtest
+  [0..0 "abc"] ""
+  [0..2 "abc"] "ab"
+  [-1..: "abc"] "c")
+
+(test (mapcar [callf list* 2 0 1 3..:] '((A B C X) (D E F Y) (G H I Z)))
+      ((C A B X) (F D E Y) (I G H Z)))