Sfairadora

  • Reference Guide

is_present

is_present(lval)
is_present(ref)
Determines, whether the specified l-value lval or reference ref (the type Dref) refers to a present data item. If the data item is mandatory (non-optional) or optional and present, the function returns TRUE. Otherwise, it returns FALSE otherwise.
If the l-value or reference does not refer to an existent data item, an error is returned.

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