From 8027e319831f02538fe431b5870d90c0267b3b78 Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Sun, 23 Jan 2011 14:39:19 +0200
Subject: Allow the options file search function to ignore the file

---
 cli/runtime-header.cxx | 10 +++++++---
 cli/runtime-source.cxx | 18 ++++++++++++++----
 doc/guide/index.xhtml  | 10 +++++++---
 3 files changed, 28 insertions(+), 10 deletions(-)

diff --git a/cli/runtime-header.cxx b/cli/runtime-header.cxx
index 41c56c9..a1cf114 100644
--- a/cli/runtime-header.cxx
+++ b/cli/runtime-header.cxx
@@ -278,9 +278,13 @@ generate_runtime_header (context& ctx)
        << endl
        << "struct option_info"
        << "{"
-       << "  const char* option;"
-       << "  std::string (*search_func) (const char*, void* arg);"
-       << "  void* arg;"
+       << "// If search_func is not NULL, it is called, with the arg" << endl
+       << "// value as the second argument, to locate the options file." << endl
+       << "// If it returns an empty string, then the file is ignored." << endl
+       << "//" << endl
+       << "const char* option;"
+       << "std::string (*search_func) (const char*, void* arg);"
+       << "void* arg;"
        << "};"
        << "argv_file_scanner (int& argc," << endl
        << "char** argv," << endl
diff --git a/cli/runtime-source.cxx b/cli/runtime-source.cxx
index 4c6b2a2..7f87d1f 100644
--- a/cli/runtime-source.cxx
+++ b/cli/runtime-source.cxx
@@ -264,8 +264,13 @@ generate_runtime_source (context& ctx)
        << "if (!base::more ())" << endl
        << "throw missing_value (oi->option);"
        << endl
-       << "if (oi->search_func != 0)" << endl
-       << "load (oi->search_func (base::next (), oi->arg));"
+       << "if (oi->search_func != 0)"
+       << "{"
+       << "std::string f (oi->search_func (base::next (), oi->arg));"
+       << endl
+       << "if (!f.empty ())" << endl
+       << "load (f);"
+       << "}"
        << "else" << endl
        << "load (base::next ());"
        << endl
@@ -420,8 +425,13 @@ generate_runtime_source (context& ctx)
        << "if (s2.empty ())" << endl
        << "throw missing_value (oi->option);"
        << endl
-       << "if (oi->search_func != 0)" << endl
-       << "load (oi->search_func (s2.c_str (), oi->arg));"
+       << "if (oi->search_func != 0)"
+       << "{"
+       << "std::string f (oi->search_func (s2.c_str (), oi->arg));"
+       << endl
+       << "if (!f.empty ())" << endl
+       << "load (f);"
+       << "}"
        << "else" << endl
        << "load (s2);"
        << "}"
diff --git a/doc/guide/index.xhtml b/doc/guide/index.xhtml
index bc215e3..638b65b 100644
--- a/doc/guide/index.xhtml
+++ b/doc/guide/index.xhtml
@@ -743,9 +743,13 @@ namespace cli
 
     struct option_info
     {
-        const char* option;
-        std::string (*search_func) (const char*, void* arg);
-        void* arg;
+      // If search_func is not NULL, it is called, with the arg
+      // value as the second argument, to locate the options file.
+      // If it returns an empty string, then the file is ignored.
+      //
+      const char* option;
+      std::string (*search_func) (const char*, void* arg);
+      void* arg;
     };
 
     argv_file_scanner (int&amp; argc,
-- 
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