@UnrelatedString hi, i notice you are here. would you have any opinions on chat.stackexchange.com/transcript/message/57174209#57174209 ?

@user41805 I was doing the haskell 99 problems and I think they said that they were based off the lisp problems which were based off the prolog ones

huh, looks like you are right, oh well can't edit it now

@user41805 interesting stuff, wish I understood it lmao

@UnrelatedString if you are interested enough, i can try explaining it to you (not today though)

it's probably just me who didn't write that message clearly enough

no, I just don't have the faintest clue how constraint logic works to begin with

i don't understand it all either, but i believe Triska's comment was addressing only a certain part of the code, for example, here's some propagation code the handles multiplication github.com/SWI-Prolog/swipl-devel/blob/master/library/clp/…

ah

basically, you've got X Y and Z, and if one or some of them is 'missing', i believe the term is not ground (the ground case is covered with nonvar/1), you can restrict their domains with the new information given by X op Y #= Z

some of these can get messy, having to consider signs of the variables and their domains 'manually', so i think Triska was addressing a better more error-prone way to generate these constraints or restrictions