top_sort/3

Availability::- use_module(library(ugraphs)).(can be autoloaded)

[semidet]top_sort(+Graph, -Sorted)

[semidet]top_sort(+Graph, -Sorted, ?Tail)

Sorted is a topological sorted list of nodes in Graph. A toplogical sort is possible if the graph is connected and acyclic. In the example we show how topological sorting works for a linear graph:

?- top_sort([1-[2], 2-[3], 3-[]], L).
L = [1, 2, 3]

The predicate top_sort/3 is a difference list version of top_sort/2.