Hello, At 07:52 10.11.05, Will Robertson wrote: >Finally, somehow the topic of extensions to pdf-e-TeX came up, and >there were some naive comments from me and some interesting comments >from Morten. I proposed the idea of something like \previouschar, >which we interpreted in two separate ways: > > - it "would return the slot number of the most recently seen char >or ligature node independently of whether we just saw a glue node or >another char/lig node; any other node type could reset it to >-1" [morten] > > - it would actually be more like LaTeX's \@ifnextchar, and look at >the input token list [me] > >Implicit in my thinking was that you could also eat up previous chars >in the same was as \unskip with a sort of fine-grained \lastbox; to >which idea Morten replied: > > This is exactly what some languages need. > > Since there are so many different node types the only safe > (IMO) way is to backtrack one node at a time so ideally we > would want the pair \lastchar and \unchar. And then we might > as well get one for each different node type. I guess someone > has to come up with a good idea about what to do with \discretionary > because I'm not at all sure what the semantics should be. by accident, this occurred to me as well, if only for a rather fun application. \lastchar and \unchar are perfect. Best, Uwe Lück.