NetEx EFT213 Reference Manual Rel 5.4

DFN and NDF FunctionsThe DFN function tests if a variable is defined. The NDF function tests if a variable is not defined.Format:Where:variableif_trueif_falseExamples:dfn(variable , if_true [ , if_false ])ndf(variable , if_true [ , if_false ])a string variable that is to be tested. A string is considered to be undefined if it has no value(i.e., null string).a string expression whose value the function takes if the test is successful.an optional string expression whose value the function takes if the test fails. If this argumentis omitted, the function takes on the value of a null string.To find out if a variable is defined, such as the variable COUNT:eFT> text {dfn(count,"YES","NO")}If COUNT was defined, the command would result in the following display:eFT: YESSet the input prompt to be the remote host variable if it is defined; otherwise use the string literal “NTXeFT”:eFT> set input prompt {} {dfn(host:remote,host:remote,"NTXeFT")}>If the remote host name is BLUESKY, the prompt would be:BLUESKY>NDF can also be used to set the input prompt to be the remote host variable or to the string literal “NTXeFT”:eFT> set input prompt {} {ndf(host:remote,“NTXeFT”,host:remote)}>eFT>If the remote host name is BLUESKY, the prompt would be:BLUESKY>Define an alias “PRINT” to output the first parameter passed to it, or to output “no parameter” if no parameteris passed.eFT> set alias print {} {ndf(1,"text no parameter","text {1}")}Execute the alias with no parameters:eFT> printeFT: no parameterNow execute the alias with the parameters “this text”:eFT> print this text:eFT: thisPage 74 Advanced Local User’s Guide REF-eFT213-R5.4-08