[Liberty-eiffel] Feature "is once then"

[Paolo Redaelli]

I found this little line in https://github.com/tybor/Liberty/blob/master/src/lib/xml/dtd/xml_dtd_validator.e

backtrack_next_pcdata_marker: UNICODE_STRING is once then U"__#PCDATA__" end

and it's puzzling me. Ok, the compiler tells me that "is" is deprecated.

I never found the "once then" syntax....

I looked into ECMA 367 and on the web but I coulnd't find any reference to such a syntax.

What does it mean?

Cheers

  Paolo who would like to have an Eiffel to _javascript_ transcompile