Mrthfx

I’m trying to use the Unicode ellipsis character (U+2026 ‘…’) in my source files. To this end, I’m looking for an ellipsis macro which I can use with newunicodechar.

The trouble is, I’ve noticed, that the spacefactor is not set correctly around ellipses. This makes solutions like those suggested at Ellipsis with a period/fullstop not work too well.

To illustrate (magnify the results):

documentclass{article}

newcommand*{egap}{kernfontdimen3font}  % Taken from the LaTeX definition

begin{document}

dots:   \

I.egap.egap.          I   quad(bad)  \

I.egap.egap.@        I   quad(good) \

I.egap.egap.egap.    I   quad(good) \

I.egap.egap.egap.@  I   quad(bad)

end{document}

The ellipsis package fixes some issues with uneven spacing, but does not correctly set the space factor. To illustrate:

documentclass{article}

usepackage[xspace]{ellipsis}

newcommand*{egap}{kernfontdimen3font}  % For comparison

begin{document}

[ellipsis]:   \

I.egap.egap.@        I   quad(good, for comparison) \

Itextellipsis          I   quad(bad)      \

Itextellipsis@        I   quad(terrible) \

Itextellipsis.         I   quad(good)     \

Itextellipsis.@       I   quad(bad)

end{document}

How can I get the spacing correct?

For restricted cases, @ifnextchar is sufficient:

documentclass{article}

usepackage[utf8]{inputenc}



newcommand*{egap}{kernfontdimen3font}

newcommand*{wordspace}{@space}

makeatletternewcommand*{elip}{.egap.egap.@ifnextchar.egapwordspace}makeatother

usepackage{newunicodechar}

newunicodechar{…}{elip}



begin{document}

macro:                  \

Ielip  I   quad(good) \

Ielip. I   quad(good)



Unicode glyph:          \

I…      I   quad(good) \

I….     I   quad(good)



But—                    \

Ielip, I   quad(bad)  \

Ielip! I   quad(bad)  \

Ielip? I   quad(bad)



end{document}

A fuller version requires a generalization of @ifnextchar. Adapting egreg’s answer to a related question leads toward such a generalization:

documentclass{article}

usepackage[utf8]{inputenc}



usepackage{xparse}

ExplSyntaxOn

NewDocumentCommand{elip}{ } { elip_main: }

NewDocumentCommand{addtoelipexceptions}{m}

{

    tl_gput_right:Nn g_elip_exceptions_tl { #1 }

}

cs_new_protected:Npn elip_gap

{

    kernfontdimen3font

}

cs_new_protected:Npn elip_main:

{

    .elip_gap.elip_gap.

    bool_set_true:N l_elip_apply_bool

    peek_catcode_ignore_spaces:NF c_space_token { elip_check: }

}

cs_new_protected:Npn elip_check:

{

    tl_map_inline:Nn g_elip_exceptions_tl

        {

            token_if_eq_charcode:NNT ##1 l_peek_token

                {bool_set_false:N l_elip_apply_bool prg_map_break: }

        }

    bool_if:NTF l_elip_apply_bool

        { @~ }

        { elip_gap }

}

tl_new:N g_elip_exceptions_tl

ExplSyntaxOff



usepackage{newunicodechar}

newunicodechar{…}{elip}



begin{document}

macro:                  \

Ielip  I   quad(good) \

Ielip. I   quad(good)



Unicode glyph:          \

I…      I   quad(good) \

I….     I   quad(good)



But—                    \

I…,     I   quad(bad)  \

I…!     I   quad(bad)  \

I…?     I   quad(bad)



addtoelipexceptions{,.!?}

Now:                    \

I…,     I   quad(good) \

I…!     I   quad(good) \

I…?     I   quad(good)

end{document}    

(Improvements to expl3 style, or an actual generalized @ifnextchar, would be welcome.)

Returning to this question…

The ellipses package exposes a hook:

RequirePackage{ellipsis}

renewcommand{ellipsis@after}{@}

newunicodechar{…}{textellipsis}

does the trick.