How to create a simple loop?

I would like to create a simple loop however I'm not very good in programing... My script is like this but instead of '...' I would like to create a loop which would work till I press return or escape. Is there any simple method?

*createbutton(5, 'Triad', 18, 0, 4, BUTTON, 'Create Triad', 'macroTriad')

*beginmacro(macroTriad) <cr>

*createlistpanel(nodes,1,'Select nodes') <cr>

*createelement(103,1,1,1) <cr>

...

*createlistpanel(nodes,1,'Select nodes') <cr>

*createelement(103,1,1,1) <cr>

*endmacro() <cr>

Kind regards,

Lukasz