Curly brackets, square brackets ... double, single ...

Summary

Diifference between double curly brackets, double square brackets, ...

Content

As a newbee to VBCS is followed a learning path compiled by John Ceccarelli, and typing stuff exactly as John prescribes, works fine :-)

Hoewever, in the property inspector I have to enclose certain input between double curly brackets: {{"Expense Report " + $page.variables.expenseReport.id}}

Somewhere else, in code view, I have to enclose certain text between double square brackets: on-click="[[$page.listeners.backButtonClicked]]"

in the same code I see the usage of single curly brackets: converter="{"option":.....

 

Can someone please explain when to use what kind of (single/double) brackets, or guide me to some documentation about it? Thanks!