diff options
| -rw-r--r-- | ChangeLog | 10 | ||||
| -rw-r--r-- | eval.c | 12 | ||||
| -rw-r--r-- | txr.1 | 14 |
3 files changed, 27 insertions, 9 deletions
@@ -1,5 +1,15 @@ 2014-07-29 Kaz Kylheku <kaz@kylheku.com> + * eval.c (repeatv): Renamed to repeat. Turned into function + with one optional argument, reflecting existing behavior. + (eval_init): Registration of repeat updated. + + * txr.1: Fixed incorrect documentation which falsely suggests + that repeat takes multiple lists, and doesn't mention + the optional count. + +2014-07-29 Kaz Kylheku <kaz@kylheku.com> + * arith.c (plus, minus, mul): Fix missing breaks to switch statements, leading to strange error messages when wrong types are passed in. @@ -3213,15 +3213,15 @@ static val repeat_times_func(val env, val lcons) return nil; } -static val repeatv(val list, val rest) +static val repeat(val list, val count) { if (!list) return nil; - if (rest) { - val count = car(rest); - if (count == zero) + + if (!missingp(count)) { + if (le(count, zero)) return nil; - return make_lazy_cons(func_f1(cons(list, cons(list, count)), + return make_lazy_cons(func_f1(cons(list, cons(list, count)), repeat_times_func)); } return make_lazy_cons(func_f1(cons(list, list), repeat_infinite_func)); @@ -3971,7 +3971,7 @@ void eval_init(void) reg_fun(intern(lit("range*"), user_package), func_n0v(range_star_v)); reg_fun(generate_s, func_n2(generate)); reg_fun(intern(lit("giterate"), user_package), func_n3o(giterate, 2)); - reg_fun(intern(lit("repeat"), user_package), func_n1v(repeatv)); + reg_fun(intern(lit("repeat"), user_package), func_n2o(repeat, 2)); reg_fun(intern(lit("force"), user_package), func_n1(force)); reg_fun(intern(lit("rperm"), user_package), func_n2(rperm)); reg_fun(intern(lit("perm"), user_package), func_n2o(perm, 1)); @@ -9062,13 +9062,21 @@ Example: Syntax: - (repeat <list1> <list>*) + (repeat <list> [<count>]) .TP Description: -The repeat function produces an infinite lazy list formed by the repeatedly -cycled catenation of the argument lists. +If <list> is empty, then repeat returns an empty list. + +If <count> is omitted, the repeat function produces an infinite lazy list +formed by catenating together copies of <list>. + +If <count> is specified and is zero or negative, then an empty list is +returned. + +Otherwise a list is returned consisting of <count> repetitions of <list> +catenated together. .SS Macros gen and gun |