unikernel/duniverse/dune_/doc/reference/actions/copy#.rst

@@ -0,0 +1,27 @@
+copy#
+-----
+
+.. highlight:: dune
+
+.. describe:: (copy# <src> <dst>)
+
+   Copy a file and add a line directive at the beginning.
+
+   Example::
+
+   (copy# config.windows.ml config.ml)
+
+   More precisely, ``copy#`` inserts the following line:
+
+   .. code:: ocaml
+
+      # 1 "<source file name>"
+
+   Most languages recognize such lines and update their current location to
+   report errors in the original file rather than the copy. This is important
+   because the copy exists only under the ``_build`` directory, and in order
+   for editors to jump to errors when parsing the build system's output, errors
+   must point to files that exist in the source tree. In the beta versions of
+   Dune, ``copy#`` was called ``copy-and-add-line-directive``. However, most of
+   time, one wants this behavior rather than a bare copy, so it was renamed to
+   something shorter.