From b6ebda4aad5b007d5cd6942e6c5a2795a881020c Mon Sep 17 00:00:00 2001
From: Karen Arutyunov <karen@codesynthesis.com>
Date: Fri, 19 Jan 2018 13:59:16 +0300
Subject: Add support for argument optional type for process high-level API

---
 libbutl/process.mxx | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

(limited to 'libbutl/process.mxx')

diff --git a/libbutl/process.mxx b/libbutl/process.mxx
index 4faa808..39a5d92 100644
--- a/libbutl/process.mxx
+++ b/libbutl/process.mxx
@@ -487,7 +487,7 @@ LIBBUTL_MODEXPORT namespace butl
   // The A arguments can be anything convertible to const char* via the
   // overloaded process_arg_as() (see below). Out of the box you can use const
   // char*, std::string, path/dir_path, (as well as [small_]vector[_view] of
-  // these), and numeric types.
+  // these), and numeric types (as well as optional<T> of all the above).
   //
   struct process_env
   {
@@ -660,6 +660,14 @@ LIBBUTL_MODEXPORT namespace butl
     v.push_back (process_arg_as (x, storage));
   }
 
+  template <typename V, typename T>
+  inline void
+  process_args_as (V& v, const optional<T>& x, std::string& storage)
+  {
+    if (x)
+      process_args_as (v, *x, storage);
+  }
+
   // [small_]vector[_view]<>
   //
   template <typename V>
-- 
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