$ sudo apt-get update
$ sudo apt-get install libexene-smlnj 

libexene-smlnj is installed in your system.

Make ensure the libexene-smlnj package were installed using the commands given below,

$ sudo dpkg-query -l | grep libexene-smlnj *

You will get with libexene-smlnj package name, version, architecture and description in a table

libexene-smlnj package basic information: