> parse "3.1"
Right (Real 3.1)


> parse "=A2+B7"
Left (Formula Add (Pair { left = { col = 1, row = 0 }, right = { col = 6, row = 1 } }))


> parse "=sum(A2:B7)"
Left (Formula Add (Range { left = { col = 1, row = 0 }, right = { col = 6, row = 1 } }))


> parse "=sum(A2:M7)"
Left (Formula Add (Range { left = { col = 1, row = 0 }, right = { col = 6, row = 12 } }))

> run C.parseIndex "a2"
Ok { col = 1, row = 0 }