[Haskell-cafe] Is it usual to read a Maybe (IORef a) ?

[Johannes Waldmann]

Timothy Goddard wrote:
> It looks like this code isn't really in fitting with normal Haskell idioms [...]

this is all very much true.

Still I understand the application area (for this example)
is interactive graph editing
and there the "in-place update" perhaps is the right model
for what the user of the program does (remove/insert node/edge).

So at least the model of the GUI needs some notion of "state"?
Of course from the GUI state one should compute the underlying
and *immutable* data object for further processing.

J.W.


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