SF.net SVN: matplotlib:[7496] trunk/matplotlib/lib/matplotlib/docstring.py

[<ef...@us...>]

Revision: 7496
          http://matplotlib.svn.sourceforge.net/matplotlib/?rev=7496&view=rev
Author:   efiring
Date:     2009-08-15 23:51:39 +0000 (Sat, 15 Aug 2009)

Log Message:
-----------
Add docstring.py; I forgot to add it when committing the Coombs patch

Added Paths:
-----------
    trunk/matplotlib/lib/matplotlib/docstring.py

Added: trunk/matplotlib/lib/matplotlib/docstring.py
===================================================================
--- trunk/matplotlib/lib/matplotlib/docstring.py	                        (rev 0)
+++ trunk/matplotlib/lib/matplotlib/docstring.py	2009-08-15 23:51:39 UTC (rev 7496)
@@ -0,0 +1,112 @@
+from matplotlib import cbook
+
+class Substitution(object):
+    """
+    A decorator to take a function's docstring and perform string
+    substitution on it.
+    
+    This decorator should be robust even if func.__doc__ is None
+    (for example, if -OO was passed to the interpreter)
+    
+    Usage: construct a docstring.Substitution with a sequence or
+    dictionary suitable for performing substitution; then
+    decorate a suitable function with the constructed object. e.g.
+    
+    sub_author_name = Substitution(author='Jason')
+    
+    @sub_author_name
+    def some_function(x):
+        "%(author)s wrote this function"
+    
+    # note that some_function.__doc__ is now "Jason wrote this function"
+    
+    One can also use positional arguments.
+    
+    sub_first_last_names = Substitution('Edgar Allen', 'Poe')
+    
+    @sub_first_last_names
+    def some_function(x):
+        "%s %s wrote the Raven"
+    """
+    def __init__(self, *args, **kwargs):
+        assert not (args and kwargs), "Only positional or keyword args are allowed"
+        self.params = args or kwargs
+
+    def __call__(self, func):
+        func.__doc__ = func.__doc__ and func.__doc__ % self.params
+        return func
+
+    def update(self, *args, **kwargs):
+        "Assume self.params is a dict and update it with supplied args"
+        self.params.update(*args, **kwargs)
+
+    @classmethod
+    def from_params(cls, params):
+        """
+        In the case where the params is a mutable sequence (list or dictionary)
+        and it may change before this class is called, one may explicitly use
+        a reference to the params rather than using *args or **kwargs which will
+        copy the values and not reference them.
+        """
+        result = cls()
+        result.params = params
+        return result
+
+class Appender(object):
+    """
+    A function decorator that will append an addendum to the docstring
+    of the target function.
+    
+    This decorator should be robust even if func.__doc__ is None
+    (for example, if -OO was passed to the interpreter).
+    
+    Usage: construct a docstring.Appender with a string to be joined to
+    the original docstring. An optional 'join' parameter may be supplied
+    which will be used to join the docstring and addendum. e.g.
+    
+    add_copyright = Appender("Copyright (c) 2009", join='\n')
+    
+    @add_copyright
+    def my_dog(has='fleas'):
+        "This docstring will have a copyright below"
+        pass
+    """
+    def __init__(self, addendum, join=''):
+        self.addendum = addendum
+        self.join = join
+
+    def __call__(self, func):
+        docitems = [func.__doc__, self.addendum]
+        func.__doc__ = func.__doc__ and ''.join(docitems)
+        return func
+
+def dedent(func):
+    "Dedent a docstring (if present)"
+    func.__doc__ = func.__doc__ and cbook.dedent(func.__doc__)
+    return func
+
+def copy(source):
+    "Copy a docstring from another source function (if present)"
+    def do_copy(target):
+        if source.__doc__:
+            target.__doc__ = source.__doc__
+        return target
+    return do_copy
+
+# create a decorator that will house the various documentation that
+#  is reused throughout matplotlib
+interpd = Substitution()
+
+def dedent_interpd(func):
+    """A special case of the interpd that first performs a dedent on
+    the incoming docstring"""
+    return interpd(dedent(func))
+
+def copy_dedent(source):
+    """A decorator that will copy the docstring from the source and
+    then dedent it"""
+    # note the following is ugly because "Python is not a functional
+    # language" - GVR. Perhaps one day, functools.compose will exist.
+    #  or perhaps not.
+    #  http://mail.python.org/pipermail/patches/2007-February/021687.html
+    return lambda target: dedent(copy(source)(target))


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