> How does it differ from existing syntax? See the examples here: > propertyChain : term '.' propertyChain > | term '?.' propertyChain > | term;
Right now you can only check if property is a null when chaining to another property to prevent a NPE. Maybe even better syntax would be: > value="prop?" > value="prop.a.b.c?" > value="prop?.a?.b?.c?" Denis Aug 23, 2011 v 1:26 PM, Igor Drobiazko: > How does it differ from existing syntax? See the examples here: > > http://tapestry.apache.org/property-expressions.html > > On Tue, Aug 23, 2011 at 1:14 PM, Denis Stepanov > <[email protected]>wrote: > >> Hello, >> >> I would like to suggest a new syntax for checking if the property >> expression value is a null: >> >>> value="?prop" >> >> >> will return false if property "prop" is null or true if not >> >>> value="?prop.a.b.c" >> >> >> will return false if property "c" is null or true if not >> >>> value="?prop?.a?.b?.c" >> >> will return false if one of the properties is null. >> >>> value="prop" >> >> >> will call toString to convert it to a boolean, is not the best way how to >> implement a null check. >> >> We have isNotNull component, which I would like to eliminate. >> >> Denis >> >> >> >> >> >> >> --------------------------------------------------------------------- >> To unsubscribe, e-mail: [email protected] >> For additional commands, e-mail: [email protected] >> >> > > > -- > Best regards, > > Igor Drobiazko > http://tapestry5.de
