(1.4)
The placeholder "~" has been improved.
You can now use the command / chest using "~".
For example, using /chest ~ ~ ~ will open the chest you are standing on. The ability to use coordinates still exists. For example /chest 2000 70 -960 will open the chest, which is located at coordinates 2000 70 -960.

You can also add any value to "~".
For example, writing "~2" will give you your block coordinate +2.
For example /chest ~4 ~2 ~ will open a chest located 4 blocks away from you on the X-axis, 2 blocks higher than you and at the same Z coordinate where you are standing.
You can write a negative number, for example "~-3", to take a coordinate 3 blocks away from you, but from the other side. So when you write the command /chest ~ ~-3 ~, you will open the chest, which is 3 blocks below you.