unikernel/duniverse/dune_/doc/reference/aliases/default.rst

@@ -0,0 +1,27 @@
+@default
+========
+
+This alias corresponds to the default argument for ``dune build``: ``dune
+build`` is equivalent to ``dune build @@default`` (``@@`` indicates a
+:doc:`non-recursive alias <../aliases>`). Similarly, ``dune build dir`` is
+equivalent to ``dune build @@dir/default``.
+
+When a directory doesn't explicitly define what the ``default`` alias means via
+an :doc:`/reference/dune/alias` stanza, the following implicit definition is
+assumed:
+
+.. code:: dune
+
+   (alias
+    (name default)
+    (deps (alias_rec all)))
+
+But if such a stanza is present in the ``dune`` file in a directory, it will be
+used instead. For example, if the following is present in ``tests/dune``,
+``dune build tests`` will run tests there:
+
+.. code:: dune
+
+   (alias
+    (name default)
+    (deps (alias_rec runtest)))