Syntax for variable arguments

There are 2 kinds of variable arguments:
    %{PropertyName} : property of the selected dataset. Properties depend on the data protocol ("kind" of data store).
    %{env:VarName} : system environment variable "$VarName"

With a multi-selection of N items, you may want to run the command N times, or only once. In the latter case, the whole arguments string will be repeated N times, using spaces as separators. If needed, you can specify which part of the string is to be repeated for each item, using the %each keyword:
    %each{pattern} : pattern will be repeated for each selected item, using spaces as separator
    %each(separator){pattern} : pattern will be repeated for each selected item, using specified separator

Examples:
    %{Project}, %{env:DISPLAY}
        1006400, :0.0
    -start %{Ident}/%{Version}
        -start Ident1/Version1 -start Ident2/Version2
    -start %each(;){%{Ident}/%{Version}}
        -start Ident1/Version1;Ident2/Version2
    -start idents=%each(;){%{Ident}} versions=%each(;){%{Version}}
        -start idents=Ident1;Ident2 versions=Version1;Version2

Warning: names of properties are case-sensitive, and can include spaces.