Re: proper way to check if a container is empty?
This WebDNA talk-list message is from 2000
It keeps the original formatting.
numero = 27127
interpreted = N
texte = >The best way is to do this:>>[showif [URL][NIS][/URL]=%5BNIS%5D]> [math show=f]NIS=0[/math]>[/showif]>>in general, because if it's possible that a variable may have user input,>they may be putting in characters that are comparison operators (like><,>,=,!) that could mess up statement. This would resolve those problems.In general this is true, but you can take advantage of the left-to-right parsing of the [ShowIf] context this way:[ShowIf =[NIS]](Notice there's only one space after the ShowIf) this reads as show if 'nothing' equals the value of the [NIS] variableNow I should also point out that this is very different from checking if a variable is undefined. It's one thing to say that a variable has been defined, and it has a value of , the empty string. It's another thing entirely to say that a variable has not been defined at all, and it has no value whatsoever.Technical Support **********************************Smith Micro, Internet Solutions Div | Formerly, Pacific Coast Software16855 West Bernardo Drive | -------------------------Suite 380 | eCommerce (WebCatalog)San Diego, CA 92127 | Software & Site Development858.675.1106 | http://www.smithmicro.com858.675.0372 (fax) **********************************-------------------------------------------------------------Brought to you by CommuniGate Pro - The Buzz Word Compliant Messaging Server.To end your Mail problems go to
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>The best way is to do this:>>[showif [url][NIS][/URL]=%5BNIS%5D]> [math show=f]NIS=0[/math]>[/showif]>>in general, because if it's possible that a variable may have user input,>they may be putting in characters that are comparison operators (like><,>,=,!) that could mess up statement. This would resolve those problems.In general this is true, but you can take advantage of the left-to-right parsing of the [showif] context this way:[ShowIf =[NIS]](Notice there's only one space after the ShowIf) this reads as show if 'nothing' equals the value of the [NIS] variableNow I should also point out that this is very different from checking if a variable is undefined. It's one thing to say that a variable has been defined, and it has a value of , the empty string. It's another thing entirely to say that a variable has not been defined at all, and it has no value whatsoever.Technical Support **********************************Smith Micro, Internet Solutions Div | Formerly, Pacific Coast Software16855 West Bernardo Drive | -------------------------Suite 380 | eCommerce (WebCatalog)San Diego, CA 92127 | Software & Site Development858.675.1106 | http://www.smithmicro.com858.675.0372 (fax) **********************************-------------------------------------------------------------Brought to you by CommuniGate Pro - The Buzz Word Compliant Messaging Server.To end your Mail problems go to .This message is sent to you because you are subscribed to the mailing list .To unsubscribe, E-mail to: To switch to the DIGEST mode, E-mail to
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