From 74af6351b2b1888cc1437e158cf29851f8e6465e Mon Sep 17 00:00:00 2001 From: Hitesh Jasani <hitesh@grokken.com> Date: Thu, 16 Jan 2014 14:42:12 -0500 Subject: Add docs for constraining and qualifying imports. --- doc/tut1.txt | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) (limited to 'doc') diff --git a/doc/tut1.txt b/doc/tut1.txt index 2070c69d6..52d46d9bd 100644 --- a/doc/tut1.txt +++ b/doc/tut1.txt @@ -1582,6 +1582,17 @@ rules apply: write(stdout, x(3)) # ambiguous: which `x` is to call? +Excluding symbols +----------------- + +The normal ``import`` statement will bring in all exported symbols. +These can be limited by naming symbols which should be excluded with +the ``except`` qualifier. + +.. code-block:: nimrod + import mymodule except y + + From statement -------------- @@ -1592,6 +1603,30 @@ exported symbols. An alternative that only imports listed symbols is the .. code-block:: nimrod from mymodule import x, y, z +The ``from`` statement can also force namespace qualification on +symbols, thereby making symbols available, but needing to be qualified +to be used. + +.. code-block:: nimrod + from mymodule import x, y, z + + x() # use x without any qualification + +.. code-block:: nimrod + from mymodule import nil + + mymodule.x() # must qualify x with the module name as prefix + + x() # using x here without qualification is a compile error + +Since module names are generally long to be descriptive, you can also +define a shorter alias to use when qualifying symbols. + +.. code-block:: nimrod + from mymodule as m import nil + + m.x() # m is aliasing mymodule + Include statement ----------------- -- cgit 1.4.1-2-gfad0