From 288bb84a935426bbc7ab43b0eb0eba98107463a1 Mon Sep 17 00:00:00 2001 From: Kaz Kylheku Date: Wed, 1 Apr 2015 07:03:19 -0700 Subject: New zap operator. * eval.c (zap_s): New global variable. (op_modplace): Support zap. (eval_init): Initialize zap_s, and register as operator. * txr.1: Documented zap. --- eval.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'eval.c') diff --git a/eval.c b/eval.c index 0807f834..2bd4121d 100644 --- a/eval.c +++ b/eval.c @@ -70,7 +70,7 @@ val cond_s, if_s, defvar_s, defun_s, defmacro_s, tree_case_s, tree_bind_s; val caseq_s, caseql_s, casequal_s; val memq_s, memql_s, memqual_s; val eq_s, eql_s, equal_s; -val inc_s, dec_s, push_s, pop_s, flip_s, gethash_s, car_s, cdr_s, not_s; +val inc_s, dec_s, push_s, pop_s, flip_s, zap_s, gethash_s, car_s, cdr_s, not_s; val del_s, vecref_s; val for_s, for_star_s, each_s, each_star_s, collect_each_s, collect_each_star_s; val append_each_s, append_each_star_s; @@ -1886,6 +1886,10 @@ static val op_modplace(val form, val env) return pop(valptr(ptr)); } else if (op == flip_s) { return deref(ptr) = null(deref(ptr)); + } else if (op == zap_s) { + val oldval = deref(ptr); + set(ptr, eval(newform, env, form)); + return oldval; } else if (op == del_s) { eval_error(form, lit("~s: cannot delete ~a"), op, place, nao); } @@ -3770,6 +3774,7 @@ void eval_init(void) push_s = intern(lit("push"), user_package); pop_s = intern(lit("pop"), user_package); flip_s = intern(lit("flip"), user_package); + zap_s = intern(lit("zap"), user_package); del_s = intern(lit("del"), user_package); for_s = intern(lit("for"), user_package); for_star_s = intern(lit("for*"), user_package); @@ -3860,6 +3865,7 @@ void eval_init(void) reg_op(push_s, op_modplace); reg_op(pop_s, op_modplace); reg_op(flip_s, op_modplace); + reg_op(zap_s, op_modplace); reg_op(del_s, op_modplace); reg_op(for_s, op_for); reg_op(for_star_s, op_for); -- cgit v1.2.3