Conditional Fail Expression
You can use a conditional fail expression in CTL1.
However, it can only be used for defining a mapping to an output field.
![[Important]](figures/important.png) | Important |
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Remember that (in interpreted mode of CTL2) this expression can be used in multiple ways: for assigning the value to a variable, mapping a value to an output field, or as an argument of a function. |
A conditional fail expressions looks like this (for one output field):
expression1 : expression2 : expression3 : ... : expressionN;
The expressions are evaluated one by one, starting from the first expression and going from left to right.
As soon as one of these expressions may successfully be mapped to the output field, it is used and the other expressions are not evaluated.
If none of these expressions may be mapped to the output field, graph fails.