diff options
| -rw-r--r-- | ChangeLog | 7 | ||||
| -rw-r--r-- | eval.c | 1 | ||||
| -rw-r--r-- | txr.1 | 22 |
3 files changed, 23 insertions, 7 deletions
@@ -1,3 +1,10 @@ +2012-01-12 Kaz Kylheku <kaz@kylheku.com> + + * eval.c (eval_init): Make lazy_appendv function + available as append*. + + * txr.1: Documented. + 2012-01-11 Kaz Kylheku <kaz@kylheku.com> Before releasing 53, there is this. @@ -1555,6 +1555,7 @@ void eval_init(void) reg_fun(intern(lit("first"), user_package), func_n1(car)); reg_fun(intern(lit("rest"), user_package), func_n1(cdr)); reg_fun(append_s, func_n0v(appendv)); + reg_fun(intern(lit("append*"), user_package), func_n0v(lazy_appendv)); reg_fun(list_s, func_n0v(identity)); reg_fun(intern(lit("identity"), user_package), identity_f); reg_fun(intern(lit("typeof"), user_package), func_n1(typeof)); @@ -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: |