diff options
| -rw-r--r-- | ChangeLog | 12 | ||||
| -rw-r--r-- | eval.c | 3 | ||||
| -rw-r--r-- | lib.c | 37 | ||||
| -rw-r--r-- | lib.h | 3 | ||||
| -rw-r--r-- | txr.1 | 48 |
5 files changed, 102 insertions, 1 deletions
@@ -1,5 +1,17 @@ 2014-01-22 Kaz Kylheku <kaz@kylheku.com> + * lib.c (conses, lazy_conses, func_set_env): New functions. + (lazy_conses_func): New static function. + + * lib.h (conses, lazy_conses, func_set_env): Declared. + + * eval.c (eval_init): conses, lazy_conses and func_set_env registered + as intrinsics. + + * txr.1: Documented. + +2014-01-22 Kaz Kylheku <kaz@kylheku.com> + Changes to the list collection mechanism to improve the extension of list operations over vectors and strings. @@ -2351,6 +2351,8 @@ void eval_init(void) reg_fun(intern(lit("fourth"), user_package), func_n1(fourth)); reg_fun(intern(lit("fifth"), user_package), func_n1(fifth)); reg_fun(intern(lit("sixth"), user_package), func_n1(sixth)); + reg_fun(intern(lit("conses"), user_package), func_n1(conses)); + reg_fun(intern(lit("conses*"), user_package), func_n1(lazy_conses)); reg_fun(intern(lit("copy-list"), user_package), func_n1(copy_list)); reg_fun(intern(lit("nreverse"), user_package), func_n1(nreverse)); reg_fun(intern(lit("reverse"), user_package), func_n1(reverse)); @@ -2668,6 +2670,7 @@ void eval_init(void) reg_fun(intern(lit("fboundp"), user_package), func_n1(fboundp)); reg_fun(intern(lit("func-get-form"), user_package), func_n1(func_get_form)); reg_fun(intern(lit("func-get-env"), user_package), func_n1(func_get_env)); + reg_fun(intern(lit("func-set-env"), user_package), func_n2(func_set_env)); reg_fun(intern(lit("functionp"), user_package), func_n1(functionp)); reg_fun(intern(lit("interp-fun-p"), user_package), func_n1(interp_fun_p)); @@ -337,6 +337,36 @@ val sixth(val cons) return car(cdr(cdr(cdr(cdr(cdr(cons)))))); } +val conses(val list) +{ + list_collect_decl (out, ptail); + + for (; consp(list); list = cdr(list)) + ptail = list_collect(ptail, list); + + return out; +} + +static val lazy_conses_func(val env, val lcons) +{ + val fun = lcons_fun(lcons); + rplaca(lcons, env); + func_set_env(fun, env = cdr(env)); + + if (env) + rplacd(lcons, make_lazy_cons(fun)); + else + rplacd(lcons, nil); + return nil; +} + +val lazy_conses(val list) +{ + if (!list) + return nil; + return make_lazy_cons(func_f1(list, lazy_conses_func)); +} + val listref(val list, val ind) { if (lt(ind, zero)) @@ -3172,6 +3202,13 @@ val func_get_env(val fun) return fun->f.env; } +val func_set_env(val fun, val env) +{ + type_check(fun, FUN); + set(fun->f.env, env); + return env; +} + val functionp(val obj) { return type(obj) == FUN ? t : nil; @@ -366,6 +366,8 @@ val third(val cons); val fourth(val cons); val fifth(val cons); val sixth(val cons); +val conses(val list); +val lazy_conses(val list); val listref(val list, val ind); val *listref_l(val list, val ind); val *tail(val cons); @@ -597,6 +599,7 @@ val func_n4o(val (*fun)(val, val, val, val), int reqargs); val func_interp(val env, val form); val func_get_form(val fun); val func_get_env(val fun); +val func_set_env(val fun, val env); val functionp(val); val interp_fun_p(val); val funcall(val fun); @@ -7027,12 +7027,58 @@ Examples: (mappend (lambda (item) (if (evenp x) (list x))) '(1 2 3 4 5)) -> (2 4) +.SS Functions conses and conses* + +.TP +Syntax: + + (conses <list>) + (conses* <list>) + +.TP +Description: + +These functions return a list whose elements are the conses which make +up <list>. The conses* function does this in a lazy way, avoiding the +computation of the entire list: it returns a lazy list of the conses of <list>. +The conses function computes the entire list before returning. + +The input <list> may be proper or improper. + +The first cons of a list is that list itself. The second cons is the rest +of the list, or (cdr <list>). The third cons is (cdr (cdr <list>)) and so on. + +.TP +Example: + + (conses '(1 2 3)) -> ((1 2 3) (2 3) (3)) + +.TP +Dialect Note: + +These functions are useful for simulating the maplist function found in +other dialects like Common Lisp. + +TXR Lisp's (conses x) can be expressed in Common Lisp as +(maplist #'identity x). + +Conversely, the Common Lisp operation (maplist function list) can be computed +in TXR Lisp as (mapcar function (conses list)). + +More generally, the Common Lisp operation + + (maplist function list0 list1 ... listn) + +can be expressed as: + + (mapcar function (conses list0) (conses list1) ... (conses listn)) + .SS Function apply .TP Syntax: -(apply <function> <arglist>) + (apply <function> <arglist>) .TP Description: |