1 files changed, 44 insertions, 0 deletions
diff --git a/build/target.txx b/build/target.txx
new file mode 100644
index 0000000..6fe3f33
--- /dev/null
+++ b/build/target.txx
@@ -0,0 +1,44 @@
+// file      : build/target.txx -*- C++ -*-
+// copyright : Copyright (c) 2014-2015 Code Synthesis Ltd
+// license   : MIT; see accompanying LICENSE file
+
+#include <build/scope>
+#include <build/utility>     // extension_pool
+#include <build/diagnostics>
+#include <build/prerequisite>
+
+namespace build
+{
+  template <const char* ext>
+  const std::string&
+  target_extension_fix (const target_key&, scope&)
+  {
+    return extension_pool.find (ext);
+  }
+
+  template <const char* var>
+  const std::string&
+  target_extension_var (const target_key& tk, scope& s)
+  {
+    auto val (s[var]);
+
+    if (!val)
+    {
+      diag_record dr;
+      dr << fail << "no default extension in variable " << var
+         << info << "required to derive file name for ";
+
+      // This is a bit hacky: we may be dealing with a target (see
+      // file::derive_path()) or prerequsite (see search_existing_file()).
+      // So we are going to check if dir is absolute. If it is, then
+      // we assume this is a target, otherwise -- prerequsite.
+      //
+      if (tk.dir->absolute ())
+        dr << "target " << tk;
+      else
+        dr << "prerequisite " << prerequisite_key {tk, &s};
+    }
+
+    return extension_pool.find (val.as<const std::string&> ());
+  }
+}