[luatex] Font control sequence names: LuaTeX versus other engines

Joseph Wright (CHE) Joseph.Wright at uea.ac.uk
Fri Dec 5 08:18:50 CET 2014

Hello all,

Testing some LaTeX NFSS code, or rather tracing why the result comes out
different in LuaTeX from pdfTeX, we've come across the following:


With all engines featuring e-TeX except LuaTeX you see

    {changing \testb=undefined}
    {into \testb=select font nullfont}
    {changing \testb=select font nullfont}
    {into \testb=select font cmr10}
    {select font cmr10}
    {reassigning current font=\testb}

and in the output box

    ...\testb T

(Knuth's TeX also goes with \testb here, but the trace is different
without e-TeX.)

With LuaTeX, in contrast, we get

    {changing \testb=undefined}
    {into \testb=select font nullfont}
    {select font cmr10}
    {reassigning current font=\testa}


    ...\testa T

Ignoring the difference in assignment detail for the font (reported
separately), the question for me here is 'Is the change of font control
sequence deliberate?'. I suspect it may be, but don't think I've seen it
documented. To be expected?
Joseph Wright

More information about the luatex mailing list