Add tables.mgetOrPutLazy #52
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| loc = val | ||
| loc | ||
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| setter(mgetOrPut(t, key, default(R))) |
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this looks pretty odd - ie if B is an array[10000, uint64], this will.. zero-init such an array, zeroinit another such array (default(R)) then compare all those values?
| type R = B | ||
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| proc setter(loc: var R): var R = | ||
| if loc == default(R): |
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so if the collection had a value that was all zeroes (as opposed to not having a value), this will update it to val which doesn't seem to be the intent
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Yes, this version of code comes with a number of caveats, but the idea of having a shim is that it allows us to capture the intention of the user until a more general and efficient version of the API is added to the tables module (as a template similar to withValue).
At the moment it's reasonable to use mostly with tables with ref values that don't need to store nil. The default function for the type should be cheap and not a valid value in the usage context.
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well, the that's the point a bit - my intent is not to set if the value is the default - it's to set / create only if it's not in the collection already
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