all: semantics of head and tail are reversed cf. the rest of the world

[gonum]

all: semantics of head and tail are reversed cf. the rest of the world

[vladimir-ch]

The above example seems to be a consequence of how concrete.DirectedGraph.AddDirectedEdge() is implemented. But the same behavior (edge direction reversed to the usual one) is suggested also by the docs for graph.DirectedGraph.EdgeTo().

By a coincidence, From/To terminology is what I am used to, so as for me, I would welcome this change.

[kortschak]

I agree, it's internally consistent (and matches how I often read head/tail), but the reduction in ambiguity would be a bonus.

[kortschak]

I would like to change Graph.Successor and Graph.Predecessor to Graph.From (successors are reachable from) and Graph.To (predecessor can lead to) respectively as well (this is in line with the gonum and Go conventions of using non-Latinate language as much as possible).