Second argument if condition is true, third argument otherwise.
| Condition | Script to evaluate. |
| IfTrue | Script to evaluate and return value of if condition evaluates to true. |
| IfFalse | Script to evaluate and return value of if condition evaluates to false. |
Note that you will most likely want the IfTrue and IfFalse arguments to use return.
For information regarding exceptions / errors, see
here.
set x 1
set y [Ter {$x == 1} {return -1} {return 1}]
-1