and
| Syntax |
expression1 and expression2 expression1 && expression2
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| Action |
The logical conjunction (boolean "and") operator, yields the boolean value true if both expression1 and expression2 evaluate to true, false otherwise.
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| Examples |
file.exists ("myFile") and (!file.exists ("myFile")) » false
This expression always evaluates to false, because it is impossible for both expressions to be true at the same time.
This expression evaluates to true if "myFile" exists and is a text file. |
| Notes |
There is no difference between the two forms, && and and. UserTalk employs "short-circuit" evaluation of boolean expressions. In other words, if expression1 of an and operation evaluates to false, expression2 will not be evaluated, since it can already be determined that the result of the operation will be false. In example #2 above, the call to file.type will never be made if file.exists returns false (i.e., the file doesn't exist).
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| See Also |
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