Three-way relationships
May. 3rd, 2007 06:43 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
jackSo, in some programming languages I can say:
x=y=0
To mean "Set y equal to nought and x equal to that[1]". In others, you'd get "Set x equal to one if y is already zero, else zero."
But in what language can I say:
if (x===y==0)
to mean "if x and y are both zero"?
The obvious problem is common operator associativity doesn't work. If the operators are nested binary operators, "y==0" would have to return two values, both the result, and "0".
You could have a system whereby you *did* return a number of things, eg. the result in list[0] and the various operators or other hints in list[1..n], and then let logic decide how to use the hints. That might also be useful where a function really really wants to return two values.
But is there a consistent way of doing this without turning it into an unreadable mess? :)
[1] Non-pedant corner: non-pedants might say "set x and y equal to nought"
x=y=0
To mean "Set y equal to nought and x equal to that[1]". In others, you'd get "Set x equal to one if y is already zero, else zero."
But in what language can I say:
if (x===y==0)
to mean "if x and y are both zero"?
The obvious problem is common operator associativity doesn't work. If the operators are nested binary operators, "y==0" would have to return two values, both the result, and "0".
You could have a system whereby you *did* return a number of things, eg. the result in list[0] and the various operators or other hints in list[1..n], and then let logic decide how to use the hints. That might also be useful where a function really really wants to return two values.
But is there a consistent way of doing this without turning it into an unreadable mess? :)
[1] Non-pedant corner: non-pedants might say "set x and y equal to nought"