init

.venv/lib/python3.8/site-packages/traitlets/utils/descriptions.py

@@ -0,0 +1,171 @@
+import inspect
+import re
+import types
+
+
+def describe(article, value, name=None, verbose=False, capital=False):
+    """Return string that describes a value
+
+    Parameters
+    ----------
+    article : str or None
+        A definite or indefinite article. If the article is
+        indefinite (i.e. "a" or "an") the appropriate one
+        will be infered. Thus, the arguments of ``describe``
+        can themselves represent what the resulting string
+        will actually look like. If None, then no article
+        will be prepended to the result. For non-articled
+        description, values that are instances are treated
+        definitely, while classes are handled indefinitely.
+    value : any
+        The value which will be named.
+    name : str or None (default: None)
+        Only applies when ``article`` is "the" - this
+        ``name`` is a definite reference to the value.
+        By default one will be infered from the value's
+        type and repr methods.
+    verbose : bool (default: False)
+        Whether the name should be concise or verbose. When
+        possible, verbose names include the module, and/or
+        class name where an object was defined.
+    capital : bool (default: False)
+        Whether the first letter of the article should
+        be capitalized or not. By default it is not.
+
+    Examples
+    --------
+    Indefinite description:
+
+    >>> describe("a", object())
+    'an object'
+    >>> describe("a", object)
+    'an object'
+    >>> describe("a", type(object))
+    'a type'
+
+    Definite description:
+
+    >>> describe("the", object())
+    "the object at '0x10741f1b0'"
+    >>> describe("the", object)
+    "the type 'object'"
+    >>> describe("the", type(object))
+    "the type 'type'"
+
+    Definitely named description:
+
+    >>> describe("the", object(), "I made")
+    'the object I made'
+    >>> describe("the", object, "I will use")
+    'the object I will use'
+    """
+    if isinstance(article, str):
+        article = article.lower()
+
+    if not inspect.isclass(value):
+        typename = type(value).__name__
+    else:
+        typename = value.__name__
+    if verbose:
+        typename = _prefix(value) + typename
+
+    if article == "the" or (article is None and not inspect.isclass(value)):
+        if name is not None:
+            result = "{} {}".format(typename, name)
+            if article is not None:
+                return add_article(result, True, capital)
+            else:
+                return result
+        else:
+            tick_wrap = False
+            if inspect.isclass(value):
+                name = value.__name__
+            elif isinstance(value, types.FunctionType):
+                name = value.__name__
+                tick_wrap = True
+            elif isinstance(value, types.MethodType):
+                name = value.__func__.__name__
+                tick_wrap = True
+            elif type(value).__repr__ in (object.__repr__, type.__repr__):
+                name = "at '%s'" % hex(id(value))
+                verbose = False
+            else:
+                name = repr(value)
+                verbose = False
+            if verbose:
+                name = _prefix(value) + name
+            if tick_wrap:
+                name = name.join("''")
+            return describe(article, value, name=name,
+                verbose=verbose, capital=capital)
+    elif article in ("a", "an") or article is None:
+        if article is None:
+            return typename
+        return add_article(typename, False, capital)
+    else:
+        raise ValueError("The 'article' argument should "
+            "be 'the', 'a', 'an', or None not %r" % article)
+
+    
+def _prefix(value):
+    if isinstance(value, types.MethodType):
+        name = describe(None, value.__self__, verbose=True) + '.'
+    else:
+        module = inspect.getmodule(value)
+        if module is not None and module.__name__ != "builtins":
+            name = module.__name__ + '.'
+        else:
+            name = ""
+    return name
+
+
+def class_of(value):
+    """Returns a string of the value's type with an indefinite article.
+
+    For example 'an Image' or 'a PlotValue'.
+    """
+    if inspect.isclass(value):
+        return add_article(value.__name__)
+    else:
+        return class_of(type(value))
+
+
+def add_article(name, definite=False, capital=False):
+    """Returns the string with a prepended article.
+
+    The input does not need to begin with a charater.
+
+    Parameters
+    ----------
+    name : str
+        Name to which to prepend an article
+    definite : bool (default: False)
+        Whether the article is definite or not.
+        Indefinite articles being 'a' and 'an',
+        while 'the' is definite.
+    capital : bool (default: False)
+        Whether the added article should have
+        its first letter capitalized or not.
+    """
+    if definite:
+        result = "the " + name
+    else:
+        first_letters = re.compile(r'[\W_]+').sub('', name)
+        if first_letters[:1].lower() in 'aeiou':
+            result = 'an ' + name
+        else:
+            result = 'a ' + name
+    if capital:
+        return result[0].upper() + result[1:]
+    else:
+        return result
+
+
+def repr_type(obj):
+    """Return a string representation of a value and its type for readable
+
+    error messages.
+    """
+    the_type = type(obj)
+    msg = '{!r} {!r}'.format(obj, the_type)
+    return msg