In article <20741.1493805...@andromeda.noi.kre.to>, Robert Elz <k...@munnari.oz.au> wrote: >I have two changes ready to commit that I thought I would let >people know about, and solicit a few opinions as to a couple of >open issues... > >The first is to implement the ";&" alternative to ";;" in case >statements - ";&" is "fallthrough", and exists in many other >shells ... actions that are connected to the following pattern >(if any) are executed after the actions for the current one (without >evaluating the pattern, or attempting to match it). > >This was approved for the next (major) version of POSIX (issue 8) >back in 2011, and is (and was) implemented in most other shells >(just not ours.) (No, I have no idea when issue8 will actually appear.) > >As an exmaple of its use, the canonical example (from the forthcoming >POSIX text) is ... > >x=0 y=1 >case 1 in > $((y=0)) ) ;; > $((x=1)) ) ;& > $((x=2)) ) echo $x.$y ;; >esac > >which is required to emit "1.0" (and does with the changes I have planned, >but not yet committed). > >The question here, is that bash (at least) also has a third form of >terminator to use instead of ";;" - ";;&". That one causes fall >through to the next pattern which matches, that is, after the commands >associated with a pattern are executed, if those commands were terminated >with ";;&" then the shell will go on to look at the next pattern, evaluate >it, see if it matches, and if so, execute its commands (and repeat if it >also ends with ";;&") - if that pattern does not match, continue looking for >one that does (ie: after executing the ";;&" commands, everything continues >more or less as if the pattern which matched had not matched after all.)
Go for it (;& and LINENO) and not bother to add the bash extension for now! christos
