How to make a diagonal line collision in Love2d?

Question

Game development

with a straight line that is perpendicular to the coordinate grid, everything is simple, I do it like this

if object.x + object.w >= col[i][1] then
      if object.x <= col[i][2] then
      if object.y + object.h >= col[i][3] then
      if object.y + object.h <= col[i][3] + 8 then
        object.y = col[i][3] - object.h

but what if you need to make a diagonal surface?