The things this author likes about NaN are also properties of NULL in many environments (that NULL cannot be compared to NULL, that operating on NULL returns NULL, etc.); so while you might not see many languages default initializing things to NaN, you do see them default initializing things to NULL with similar effect.
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The things this author likes about NaN are also properties of NULL in many environments (that NULL cannot be compared to NULL, that operating on NULL returns NULL, etc.); so while you might not see many languages default initializing things to NaN, you do see them default initializing things to NULL with similar effect.
Except this is actually worse, since there are many possible values which evaluate to NaN.
EDIT: I do not know how D implements NaNs; they may have magic to make them more sane to work with.
D does not implement NaNs, it just relies on the IEEE FP hardware to do it.
What D does do is expose NaNs so the programmer can rely on their existence and use them in a straightforward manner.