This package provides auto-complete feature in GAMS mode. To use this package, you first need GAMS mode (gams-mode.el) and auto-complete mode. You can install GAMS mode and auto-complete mode from MELPA. Put this file into your load-path and add the following into your init.el file. (require 'gams-ac) (gams-ac-after-init-setup) If you want to add more keywords, for example, "computable", "general", "equilibrium", Add the following into your init.el. (setq gams-ac-source-user-keywords-list '("computable" "general" "equilibrium"))