Ceki Gulcu escribió: > Hello Diego, > > The special syntax originates from Bash, at least that's where I saw it fist. > > http://www.faqs.org/docs/abs/HTML/parameter-substitution.html > http://tldp.org/LDP/abs/html/refcards.html#AEN20779 > http://www.purinchu.net/wp/2005/06/11/advanced-parameter-substitution-with-bash/ > > Thus, "${varnname:-word}" means, if varname exists and isn't null, return its > value, otherwise return 'word'. > > If my memory serves me correctly, the special substitution syntax is needed > because, we would like to have the name of the parameter to vary with the > circumstances. More precisely, while most database drivers take expect the > name > of the "url" parameter to be "url", some database drivers expect that the > value > be passed using a different variable name. > > Does this help? > > Diego Louzán wrote: >> In chapter4 of the documentation the following example is shown: >> >> <dataSource class="${dataSourceClass}"> >> <!-- Joran cannot substitute variables >> that are not attribute values. Therefore, we cannot >> declare the next parameter like the others. >> --> >> <param name="${url-key:-url}" value="${url_value}"/> >> <serverName>${serverName}</serverName> >> <databaseName>${databaseName}</databaseName> >> </dataSource> >> >> I can't figure out that special syntax for Joran in "${url-key:-url}", >> can anybody explain it to me? Why is it needed in that example? >> >> Regards. >> Diego.
I'm not much of a bash fan, so no wonder I had never heard about that syntax xD Thanks for clearing that up. Regards. Diego. _______________________________________________ Logback-user mailing list [email protected] http://qos.ch/mailman/listinfo/logback-user
