From 4ad96a94657fe688da3f89102c5cc0decd268037 Mon Sep 17 00:00:00 2001
From: Kaz Kylheku <kaz@kylheku.com>
Date: Sun, 9 Oct 2016 10:15:47 -0700
Subject: New function: args_cat_zap_from.

* args.c (args_cat_zap): New function.

* args.c (args_cat_zap): Declared.
---
 args.c | 10 ++++++++++
 args.h |  1 +
 2 files changed, 11 insertions(+)

diff --git a/args.c b/args.c
index 7c62baee..9377d357 100644
--- a/args.c
+++ b/args.c
@@ -97,6 +97,16 @@ struct args *args_cat_zap(struct args *to, struct args *from)
   return to;
 }
 
+struct args *args_cat_zap_from(struct args *to, struct args *from, cnum index)
+{
+  size_t size = sizeof *from->arg * (from->fill - index);
+  to->list = from->list;
+  memcpy(to->arg + to->fill, from->arg + index, size);
+  to->fill += from->fill - index;
+  memset(from->arg, 0, size);
+  return to;
+}
+
 val args_copy_to_list(struct args *args)
 {
   list_collect_decl (out, ptail);
diff --git a/args.h b/args.h
index c9f6bd9a..68d301b8 100644
--- a/args.h
+++ b/args.h
@@ -185,4 +185,5 @@ val args_get_checked(val name, struct args *args, cnum *arg_index);
 struct args *args_copy(struct args *to, struct args *from);
 struct args *args_copy_zap(struct args *to, struct args *from);
 struct args *args_cat_zap(struct args *to, struct args *from);
+struct args *args_cat_zap_from(struct args *to, struct args *from, cnum index);
 val args_copy_to_list(struct args *args);
-- 
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