This is a direct port from the TextMate package. It includes syntax highlighting and snippets for core language constructs and standard libraries.
If you want to use custom snippets, it's best to put them in your custom file. Chose the Atom Menu, then Snippets and a file will open. The syntax for snippets is like the code below:
".source.monkey"
"DrawCircle":
prefix: 'DrawCircle'
body: 'DrawCircle(${1:x}, ${2:y}, ${3:radius})$0'
"DrawRect":
prefix: 'DrawRect'
body: 'DrawRect(${1:x}, ${2:y}, ${3:width}, ${4:height})$0'
And THEN I have gutted this because I didn't understand how it worked and added very crude syntax highlighting for cerberus-x files.
For more info and how to further improve Atom for Cerberus-X visit the official forums: Cerberus X