Metadata-Version: 1.1
Name: toposort
Version: 0.2
Summary: Implements a topological sort algorithm.
Home-page: https://bitbucket.org/ericvsmith/toposort
Author: Eric V. Smith
Author-email: eric@trueblade.com
License: Apache License Version 2.0
Description: ========
        toposort
        ========
        
        Overview
        ========
        
        Implements a topological sort algorithm.
        
        From `Wikipedia <http://en.wikipedia.org/wiki/Topological_sorting>`_:
        In computer science, a topological sort (sometimes abbreviated topsort
        or toposort) or topological ordering of a directed graph is a linear
        ordering of its vertices such that for every directed edge uv from
        vertex u to vertex v, u comes before v in the ordering.
        
        Input data description
        ======================
        
        The input to the toposort function is a dict describing the
        dependencies among the input nodes. Each key is a dependent node, the
        corresponding value is a set containing the dependent nodes.
        
        Note that toposort does not care what the input node values mean: it
        just compares them for equality. The examples here usually use
        integers, but they could be any hashable type.
        
        Typical usage
        =============
        
        The interpretation of the input data here is: If 2 depends on 11; 9
        depends on 11, 8 and 10; 10 depends on 11 and 3 (and so on), then in what
        order should we process the items such that all nodes are processed
        before any of their dependencies?::
        
            >>> from toposort import toposort, toposort_flatten
            >>> list(toposort({2: {11},
            ...                9: {11, 8, 10},
            ...                10: {11, 3},
            ...                11: {7, 5},
            ...                8: {7, 3},
            ...               }))
            [{3, 5, 7}, {8, 11}, {2, 10}, {9}]
        
        And the answer is: process 3, 5, and 7 (in any order); then process 8
        and 11; then process 2 and 10; then process 9. Note that 3, 5, and 7
        are returned first because they do not depend on anything. They are
        then removed from consideration, and then 8 and 11 don't depend on
        anything remaining. This process continues until all nodes are
        returned, or a circular dependency is detected.
        
        Circular dependencies
        =====================
        
        A circular dependency will raise a ValueError. Here 1 depends on 2,
        and 2 depends on 1::
        
            >>> list(toposort({1: {2},
            ...                2: {1},
            ...               }))
            Traceback (most recent call last):
                ...
            ValueError: Cyclic dependencies exist among these items: (1, {2}), (2, {1})
        
        
        Module contents
        ===============
        
        ``toposort(data)``
        
        Returns an iterator describing the dependencies among nodes in the
        input data. Each returned item will be a set. Each member of this set
        has no dependencies in this set, or in any set previously returned.
        
        ``toposort_flatten(data, sort=True)``
        
        Like toposort(data), except that it returns a list of all of the
        depend values, in order. If sort is true, the returned nodes are sorted within
        each group before they are appended to the result::
        
            >>> toposort_flatten({2: {11},
            ...                   9: {11, 8, 10},
            ...                   10: {11, 3},
            ...                   11: {7, 5},
            ...                   8: {7, 3},
            ...                  })
            [3, 5, 7, 8, 11, 2, 10, 9]
        
        Note that this result is the same as the first example: ``[{3, 5, 7}, {8, 11}, {2, 10}, {9}]``,
        except that the result is flattened, and within each set the nodes
        are sorted.
        
        Change log
        ==========
        
        0.2 2014-02-10 Eric V. Smith
        ----------------------------
        
        * Modify setup.py to produce python-toposort for bdist_rpm.
        
        0.1 2014-02-10 Eric V. Smith
        ----------------------------
        
        * Initial release.
        
Platform: UNKNOWN
Classifier: Development Status :: 5 - Production/Stable
Classifier: Intended Audience :: Developers
Classifier: License :: OSI Approved :: Apache Software License
Classifier: Topic :: Software Development :: Libraries :: Python Modules
Classifier: Programming Language :: Python :: 2.7
Classifier: Programming Language :: Python :: 3.3
