Explain properties of the lt keyword for sorting
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simeonschaub
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Jun 1, 2021
base/sort.jl
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| !!! warn | ||
| The `lt` function must be a "less than" function (as opposed to a "less than or equal" function), | ||
| i.e., for every `x` and `y`, only one of `lt(x,y)` and `lt(y,x)` can return `true`. |
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This seems a bit pedantic to me here, obviously "less than" is not the same as "less than or equal". Perhaps we could mention that "for every x and y, only one of lt(x,y) and lt(y,x) can return true." in the block above though.
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Okay, I have removed the warning block and added the note to the paragraph above.
|
Thanks! |
shirodkara
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Jun 9, 2021
* Explain restrictions on lt functions * Remove warn block, add note in text
johanmon
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Jul 5, 2021
* Explain restrictions on lt functions * Remove warn block, add note in text
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The
sort!docstring does not explain what kind of properties the functionltneeds to have (mainly that it must be irreflexive, like < and unlike ≤). This can lead to confusion (see this discourse thread for example), so it would be good to add a note.I tried to avoid technical terms like “strict total order”, but maybe the note could be more precise?