https://github.com/bungle/lua-resty-tsort

Performs a topological sort on input data.
https://github.com/bungle/lua-resty-tsort

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Performs a topological sort on input data.

• Host: GitHub
• URL: https://github.com/bungle/lua-resty-tsort
• Owner: bungle
• License: bsd-2-clause
• Created: 2016-04-05T12:11:09.000Z (over 8 years ago)
• Default Branch: master
• Last Pushed: 2016-04-07T15:20:24.000Z (over 8 years ago)
• Last Synced: 2024-02-15T01:34:49.645Z (8 months ago)
• Language: Lua
• Size: 17.6 KB
• Stars: 11
• Watchers: 4
• Forks: 4
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGES.txt
  • License: LICENSE

Awesome Lists containing this project

• awesome-resty - lua-resty-tsort

README

        
# lua-resty-tsort

Performs a topological sort on input data.

## Synopsis

```lua

local dump  = require "pl.pretty".dump

local tsort = require "resty.tsort"

local graph = tsort.new()

graph:add('a', 'b')

graph:add('b', 'c')

graph:add('0', 'a')

dump(graph:sort())

-- Output:

-- {

--   "0",

--   "a",

--   "b",

--   "c"

-- }

graph:add('1', '2', '3', 'a');

dump(graph:sort())

-- Output:

-- {

--   "0",

--   "1",

--   "2",

--   "3",

--   "a",

--   "b",

--   "c"

-- }

graph:add{'1', '1.5'};

graph:add{'1.5', 'a'};

dump(graph:sort())

-- Output:

-- {

--   "0",

--   "1",

--   "2",

--   "3",

--   "1.5",

--   "a",

--   "b",

--   "c"

-- }

graph:add('first', 'second');

graph:add('second', 'third', 'first');

local sorted, err = graph:sort()

-- Returns:

-- sorted = nil

-- err = "There is a circular dependency in the graph. It is not possible to derive a topological sort."

```

## Alternatives

Before developing this library, I asked on #lua channel on Freenode if anyone knows a library that does

topological sort. I also tried to search for a library. Unfortunately I didn't find anything. But, there

was already a library from the great [@starius](https://github.com/starius) called [toposort](https://github.com/starius/toposort/).

`toposort` looks really nice and it has a lot more features compared to `lua-resty-tsort` (also code, 245 lines vs. 58 lines).

So you may want to take a look to that as well especially if you are looking for a more full featured library.

I have not benchmarked these libs or compared them to C-implementation of tsort or other alternatives. If your graph

is not too big, say you use these to sort Javascript / CSS files or something similar, I think the performance

is not an issue.

## License

`lua-resty-tsort` uses two clause BSD license.

```

Copyright (c) 2016, Aapo Talvensaari

All rights reserved.

Redistribution and use in source and binary forms, with or without modification,

are permitted provided that the following conditions are met:

* Redistributions of source code must retain the above copyright notice, this

  list of conditions and the following disclaimer.

* Redistributions in binary form must reproduce the above copyright notice, this

  list of conditions and the following disclaimer in the documentation and/or

  other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND

ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED

WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE

DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR

ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES

(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;

LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON

ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS

SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

```