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authorKaz Kylheku <kaz@kylheku.com>2012-01-12 16:15:16 -0800
committerKaz Kylheku <kaz@kylheku.com>2012-01-12 16:15:16 -0800
commit684f80f6f119a3234aeefd1ceaa7120b6b995b1e (patch)
tree01502c4fac0a1e8f9a2256148151080d02cbe63d /txr.1
parent8d03c978be83beccae1dd9c00cf310a6d4f93eae (diff)
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* eval.c (eval_init): Make lazy_appendv function
available as append*. * txr.1: Documented.
Diffstat (limited to 'txr.1')
-rw-r--r--txr.122
1 files changed, 15 insertions, 7 deletions
diff --git a/txr.1 b/txr.1
index 0b4aa684..fd28fd49 100644
--- a/txr.1
+++ b/txr.1
@@ -5331,12 +5331,13 @@ Examples:
(second '(1 2)) -> 2
(third '(1 2 . 3)) -> **error**
-.SS Function append
+.SS Functions append and append*
.TP
Syntax:
-(append [<list>* <cdr>])
+(append [<list>* <last-arg>])
+(append* [<list>* <last-arg>])
.TP
Description:
@@ -5349,11 +5350,18 @@ If a single argument is specified, then append simply returns the value of that
argument. It may be any kind of object.
If N arguments are specified, where N > 1, then the first N-1 arguments must be
-proper lists. Copies of these lists are catenated together. The last argument,
-argument N, may be any kind of object. It is installed into the cdr field of
-the last cons cell of the resulting list. Thus, if argument N is also a list, it
-is catenated onto the resulting list, but without being copied. Argument N may
-be an atom other than nil; in that case append produces an improper list.
+proper lists. Copies of these lists are catenated together. The last argument
+N, shown in the above syntax as <last-arg>, may be any kind of object. It is
+installed into the cdr field of the last cons cell of the resulting list.
+Thus, if argument N is also a list, it is catenated onto the resulting list,
+but without being copied. Argument N may be an atom other than nil; in that
+case append produces an improper list.
+
+The append* function works like append, but returns a lazy list which produces
+the catenation of the lists on demand. If some of the arguments are
+themselves lazy lists which are infinite, then append* can return immediately,
+whereas append will get caught in an infinite loop trying to produce a
+catenation and eventually exhaust available memory.
.TP
Examples: