symmetry

I have a data type data Time = Time {hour :: Int, minute :: Int } for which i have defined the instance of Show as being instance Show Time where show (Time hour minute) = (if hour > 10 then (show hour) else ("0" ++ show hour)) ++ ":" ++ (if minute > 10 then (show minute) else ("0" ++ show minute)) which prints out times in a format of 07:09 . Now, there should be symmetry between Show and Read , so after reading (but not truly (i think) understanding) this and this , and reading the documentation , i have come up with the following code: instance Read Time where readsPrec _ input = let

For my application I need to represent simultaneously (on the same graph) two relations: one is simmetric, the other is not. Targets: Ideally the two relation should result in edges having different colors; For the symmetric relation I would like not to have double-edges; Is there a way of doing this with dot ? digraph { A; B; C subgraph Rel1 { edge [dir=none, color=red] A -> B -> C -> A } subgraph Rel2 { edge [color=blue] B -> C C -> A } } 来源： https://stackoverflow.com/questions/13236975/graphviz-dot-mix-directed-and-undirected

Lets say we have two branches ( B and C ) that have diverged from a common ancestor A . Will merging from B to C produce the same result as merging from C to B ? A | / \ B C To clarify- I'm assuming that any manual merge conflict resolutions will occur in both directions. But will any automatic merges that occur result in the same code being chosen? This is what I'm assuming, since the commit dates are identical in both directions. To further clarify - I know that the actual merging results in "mirror images" of each other based on the direction. I'm just asking about the automatically