Non-italic (roman) subscripts in math mode












5














Is there a way to set indices (subscripts) to non-italic globally? I'm aware of the case by case



X_{text{text goes here}}


But I'm having to change that across a whole document is becoming a pain.










share|improve this question
























  • The following is not an answer but a remark. With text the font will change with the surrounding text, so it'll e.g. be italic inside a theorem environment. This is probably undesirable, so I would recommend using textnormal instead.
    – Circumscribe
    Dec 18 '18 at 18:31










  • It is possible to overload _ to do this, but it might break things. Might defining newcommand*subtxt[1]{_{textnormal{#1}}} and doing a search-and-replace for _subtxt be a good alternative?
    – Circumscribe
    Dec 18 '18 at 18:38










  • see e.g. tex.stackexchange.com/a/228606/2388
    – Ulrike Fischer
    Dec 18 '18 at 18:38










  • @Circumscribe thanks! I'll give that a try!
    – Andy Grey
    Dec 18 '18 at 18:40






  • 1




    Please also confirm that really all letters in subscript positions should be rendered in upright ("roman") letters. E.g., should the letters i and j in x_i and y_j be typeset using upright letters? Or should only groups of 2 or more, or 3 or more, letters in subscript positions be typeset using roman characters?
    – Mico
    Dec 18 '18 at 19:43
















5














Is there a way to set indices (subscripts) to non-italic globally? I'm aware of the case by case



X_{text{text goes here}}


But I'm having to change that across a whole document is becoming a pain.










share|improve this question
























  • The following is not an answer but a remark. With text the font will change with the surrounding text, so it'll e.g. be italic inside a theorem environment. This is probably undesirable, so I would recommend using textnormal instead.
    – Circumscribe
    Dec 18 '18 at 18:31










  • It is possible to overload _ to do this, but it might break things. Might defining newcommand*subtxt[1]{_{textnormal{#1}}} and doing a search-and-replace for _subtxt be a good alternative?
    – Circumscribe
    Dec 18 '18 at 18:38










  • see e.g. tex.stackexchange.com/a/228606/2388
    – Ulrike Fischer
    Dec 18 '18 at 18:38










  • @Circumscribe thanks! I'll give that a try!
    – Andy Grey
    Dec 18 '18 at 18:40






  • 1




    Please also confirm that really all letters in subscript positions should be rendered in upright ("roman") letters. E.g., should the letters i and j in x_i and y_j be typeset using upright letters? Or should only groups of 2 or more, or 3 or more, letters in subscript positions be typeset using roman characters?
    – Mico
    Dec 18 '18 at 19:43














5












5








5


1





Is there a way to set indices (subscripts) to non-italic globally? I'm aware of the case by case



X_{text{text goes here}}


But I'm having to change that across a whole document is becoming a pain.










share|improve this question















Is there a way to set indices (subscripts) to non-italic globally? I'm aware of the case by case



X_{text{text goes here}}


But I'm having to change that across a whole document is becoming a pain.







math-mode subscripts






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited Dec 18 '18 at 20:49









Mico

274k30370756




274k30370756










asked Dec 18 '18 at 18:09









Andy Grey

504




504












  • The following is not an answer but a remark. With text the font will change with the surrounding text, so it'll e.g. be italic inside a theorem environment. This is probably undesirable, so I would recommend using textnormal instead.
    – Circumscribe
    Dec 18 '18 at 18:31










  • It is possible to overload _ to do this, but it might break things. Might defining newcommand*subtxt[1]{_{textnormal{#1}}} and doing a search-and-replace for _subtxt be a good alternative?
    – Circumscribe
    Dec 18 '18 at 18:38










  • see e.g. tex.stackexchange.com/a/228606/2388
    – Ulrike Fischer
    Dec 18 '18 at 18:38










  • @Circumscribe thanks! I'll give that a try!
    – Andy Grey
    Dec 18 '18 at 18:40






  • 1




    Please also confirm that really all letters in subscript positions should be rendered in upright ("roman") letters. E.g., should the letters i and j in x_i and y_j be typeset using upright letters? Or should only groups of 2 or more, or 3 or more, letters in subscript positions be typeset using roman characters?
    – Mico
    Dec 18 '18 at 19:43


















  • The following is not an answer but a remark. With text the font will change with the surrounding text, so it'll e.g. be italic inside a theorem environment. This is probably undesirable, so I would recommend using textnormal instead.
    – Circumscribe
    Dec 18 '18 at 18:31










  • It is possible to overload _ to do this, but it might break things. Might defining newcommand*subtxt[1]{_{textnormal{#1}}} and doing a search-and-replace for _subtxt be a good alternative?
    – Circumscribe
    Dec 18 '18 at 18:38










  • see e.g. tex.stackexchange.com/a/228606/2388
    – Ulrike Fischer
    Dec 18 '18 at 18:38










  • @Circumscribe thanks! I'll give that a try!
    – Andy Grey
    Dec 18 '18 at 18:40






  • 1




    Please also confirm that really all letters in subscript positions should be rendered in upright ("roman") letters. E.g., should the letters i and j in x_i and y_j be typeset using upright letters? Or should only groups of 2 or more, or 3 or more, letters in subscript positions be typeset using roman characters?
    – Mico
    Dec 18 '18 at 19:43
















The following is not an answer but a remark. With text the font will change with the surrounding text, so it'll e.g. be italic inside a theorem environment. This is probably undesirable, so I would recommend using textnormal instead.
– Circumscribe
Dec 18 '18 at 18:31




The following is not an answer but a remark. With text the font will change with the surrounding text, so it'll e.g. be italic inside a theorem environment. This is probably undesirable, so I would recommend using textnormal instead.
– Circumscribe
Dec 18 '18 at 18:31












It is possible to overload _ to do this, but it might break things. Might defining newcommand*subtxt[1]{_{textnormal{#1}}} and doing a search-and-replace for _subtxt be a good alternative?
– Circumscribe
Dec 18 '18 at 18:38




It is possible to overload _ to do this, but it might break things. Might defining newcommand*subtxt[1]{_{textnormal{#1}}} and doing a search-and-replace for _subtxt be a good alternative?
– Circumscribe
Dec 18 '18 at 18:38












see e.g. tex.stackexchange.com/a/228606/2388
– Ulrike Fischer
Dec 18 '18 at 18:38




see e.g. tex.stackexchange.com/a/228606/2388
– Ulrike Fischer
Dec 18 '18 at 18:38












@Circumscribe thanks! I'll give that a try!
– Andy Grey
Dec 18 '18 at 18:40




@Circumscribe thanks! I'll give that a try!
– Andy Grey
Dec 18 '18 at 18:40




1




1




Please also confirm that really all letters in subscript positions should be rendered in upright ("roman") letters. E.g., should the letters i and j in x_i and y_j be typeset using upright letters? Or should only groups of 2 or more, or 3 or more, letters in subscript positions be typeset using roman characters?
– Mico
Dec 18 '18 at 19:43




Please also confirm that really all letters in subscript positions should be rendered in upright ("roman") letters. E.g., should the letters i and j in x_i and y_j be typeset using upright letters? Or should only groups of 2 or more, or 3 or more, letters in subscript positions be typeset using roman characters?
– Mico
Dec 18 '18 at 19:43










4 Answers
4






active

oldest

votes


















9














It is possible to overload _ to set all subscripts in roman type, but that seems like a bad idea since it might break something unexpected.



You may instead want to consider defining a macro that produces an upright subscript. I've defined such a macro (subtxt) below.
Since it seems unlikely that you'll need underscores in math mode, I've also redefined _ to expand to subtxt whenever it is used in math mode (and to produce an underscore otherwise, like normal).



documentclass{article}

usepackage{amsmath} %% <- necessary for correct scaling of subscripts

begin{document}

newcommand*subtxt[1]{_{textnormal{#1}}}
DeclareRobustCommand_{ifmmodeexpandaftersubtxtelsetextunderscorefi}

[
X_i + Xsubtxt{i} + X_i + X_{text goes here}
]

end{document}


output



Notes:




  • I'm using textnormal instead of text because the font of subscripts created with the latter command changes based on the surrounding text. You for instance probably wouldn't want all of your subscripts inside theorem environments to be in italics. See e.g. this answer for more info.


  • I'm using DeclareRobustCommand to redefine _ because the original version of this macro is also defined like that. It isn't too important, but more information can be found here.



Unless you're using underscores for some other purpose in your document, you can now do a search-and-replace to change every _ into _.






share|improve this answer































    5














    enter image description here



    documentclass{article}

    begin{document}
    sbox0{$$}

    scriptfont1=scriptfont0


    $X_{abc}+y_{max}$


    end{document}


    Note this affects all math uses of the script size font not just subscripts.






    share|improve this answer





















    • Would that work for equation, align and other environments?
      – Andy Grey
      Dec 18 '18 at 19:22










    • @AndyGrey yes..
      – David Carlisle
      Dec 18 '18 at 19:24






    • 2




      What kind of sorcery is sbox0{$$} for? Just loading the math fonts?
      – Werner
      Dec 18 '18 at 21:35






    • 1




      @Werner latex delays finalizing the math setup until the first use of math at each font size, so that you can switch math fonts. actually for basic math at normalsize it probably makes no difference as things are pre-loaded, but it's a good habit to make sure...
      – David Carlisle
      Dec 18 '18 at 21:48








    • 1




      $x_{max}$ worksfootnote{But $X_{max}$ doesn't} and what about $x_{max}$?
      – egreg
      Dec 18 '18 at 22:32



















    5














    Here's a LuaLaTeX-based solution. Subscripts enclosed by curly braces are typeset with upright ("roman") letters, as long as there's no space between the _ (underscore) character and the material enclosed in curly braces. If a subscript term is not enclosed in curly braces, e.g., $x_i$, it's not processed by the Lua code.



    If, for some reason, you do not want to the Lua function to operate on a subscript term encased in curly braces, just make sure that there are one or more spaces between _ and the subscript term. An obvious reason for wanting to suspend operation of the Lua function would be the fact that the subscript term contains math material which should be processed in math mode.



    To activate operations, issue the instruction upsubOn. To terminate them completely, execute upsubOff.



    enter image description here



    % !TEX TS-program = lualatex
    documentclass{article}

    usepackage{amsmath,unicode-math}
    usepackage{luacode}
    %% Lua-side code:
    begin{luacode}


    function sub_up ( s )
    return ( s:gsub ( "_(%b{})" , "_{\textnormal%1}" ) )
    end


    end{luacode}
    %% LaTeX-side code:
    newcommandupsubOn{directlua{luatexbase.add_to_callback(
    "process_input_buffer" , sub_up , "subup" )}}
    newcommandupsubOff{directlua{luatexbase.remove_from_callback(
    "process_input_buffer" , "subup" )}}
    AtBeginDocument{upsubOn} % activate the Lua function by default

    begin{document}
    $X_{text goes here}$quad $x_ {ab cd}$quad $x_ {i_j},x_k^u$

    upsubOff
    $X_{text goes here}$quad $x_ {ab cd}$quad $x_ {i_j},x_k^u$
    end{document}





    share|improve this answer





























      5














      I suggest to use a different character for those subscripts. One way could be to use ? that's very rarely used in math mode. Another uses (maybe you can find a way to type it easily).



      documentclass{article}
      usepackage{amsmath}
      usepackage{newunicodechar} % for using ↓

      % the main command
      newcommand{uprightsubscript}[1]{_{textnormal{#1}}}

      % this sets up the use of ?
      begingrouplccode`~=`?lowercase{endgrouplet~}uprightsubscript
      AtBeginDocument{mathcode`?="8000 }

      % this sets up the use of ↓
      newunicodechar{↓}{uprightsubscript}

      textheight=2cm % just for making a smaller picture

      begin{document}

      $x?{max}$ worksfootnote{Also here $x?{max}$} and again $x?{max}$?

      $x↓{max}$ worksfootnote{Also here $x↓{max}$} and again $x↓{max}$?

      end{document}


      enter image description here






      share|improve this answer





















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        4 Answers
        4






        active

        oldest

        votes








        4 Answers
        4






        active

        oldest

        votes









        active

        oldest

        votes






        active

        oldest

        votes









        9














        It is possible to overload _ to set all subscripts in roman type, but that seems like a bad idea since it might break something unexpected.



        You may instead want to consider defining a macro that produces an upright subscript. I've defined such a macro (subtxt) below.
        Since it seems unlikely that you'll need underscores in math mode, I've also redefined _ to expand to subtxt whenever it is used in math mode (and to produce an underscore otherwise, like normal).



        documentclass{article}

        usepackage{amsmath} %% <- necessary for correct scaling of subscripts

        begin{document}

        newcommand*subtxt[1]{_{textnormal{#1}}}
        DeclareRobustCommand_{ifmmodeexpandaftersubtxtelsetextunderscorefi}

        [
        X_i + Xsubtxt{i} + X_i + X_{text goes here}
        ]

        end{document}


        output



        Notes:




        • I'm using textnormal instead of text because the font of subscripts created with the latter command changes based on the surrounding text. You for instance probably wouldn't want all of your subscripts inside theorem environments to be in italics. See e.g. this answer for more info.


        • I'm using DeclareRobustCommand to redefine _ because the original version of this macro is also defined like that. It isn't too important, but more information can be found here.



        Unless you're using underscores for some other purpose in your document, you can now do a search-and-replace to change every _ into _.






        share|improve this answer




























          9














          It is possible to overload _ to set all subscripts in roman type, but that seems like a bad idea since it might break something unexpected.



          You may instead want to consider defining a macro that produces an upright subscript. I've defined such a macro (subtxt) below.
          Since it seems unlikely that you'll need underscores in math mode, I've also redefined _ to expand to subtxt whenever it is used in math mode (and to produce an underscore otherwise, like normal).



          documentclass{article}

          usepackage{amsmath} %% <- necessary for correct scaling of subscripts

          begin{document}

          newcommand*subtxt[1]{_{textnormal{#1}}}
          DeclareRobustCommand_{ifmmodeexpandaftersubtxtelsetextunderscorefi}

          [
          X_i + Xsubtxt{i} + X_i + X_{text goes here}
          ]

          end{document}


          output



          Notes:




          • I'm using textnormal instead of text because the font of subscripts created with the latter command changes based on the surrounding text. You for instance probably wouldn't want all of your subscripts inside theorem environments to be in italics. See e.g. this answer for more info.


          • I'm using DeclareRobustCommand to redefine _ because the original version of this macro is also defined like that. It isn't too important, but more information can be found here.



          Unless you're using underscores for some other purpose in your document, you can now do a search-and-replace to change every _ into _.






          share|improve this answer


























            9












            9








            9






            It is possible to overload _ to set all subscripts in roman type, but that seems like a bad idea since it might break something unexpected.



            You may instead want to consider defining a macro that produces an upright subscript. I've defined such a macro (subtxt) below.
            Since it seems unlikely that you'll need underscores in math mode, I've also redefined _ to expand to subtxt whenever it is used in math mode (and to produce an underscore otherwise, like normal).



            documentclass{article}

            usepackage{amsmath} %% <- necessary for correct scaling of subscripts

            begin{document}

            newcommand*subtxt[1]{_{textnormal{#1}}}
            DeclareRobustCommand_{ifmmodeexpandaftersubtxtelsetextunderscorefi}

            [
            X_i + Xsubtxt{i} + X_i + X_{text goes here}
            ]

            end{document}


            output



            Notes:




            • I'm using textnormal instead of text because the font of subscripts created with the latter command changes based on the surrounding text. You for instance probably wouldn't want all of your subscripts inside theorem environments to be in italics. See e.g. this answer for more info.


            • I'm using DeclareRobustCommand to redefine _ because the original version of this macro is also defined like that. It isn't too important, but more information can be found here.



            Unless you're using underscores for some other purpose in your document, you can now do a search-and-replace to change every _ into _.






            share|improve this answer














            It is possible to overload _ to set all subscripts in roman type, but that seems like a bad idea since it might break something unexpected.



            You may instead want to consider defining a macro that produces an upright subscript. I've defined such a macro (subtxt) below.
            Since it seems unlikely that you'll need underscores in math mode, I've also redefined _ to expand to subtxt whenever it is used in math mode (and to produce an underscore otherwise, like normal).



            documentclass{article}

            usepackage{amsmath} %% <- necessary for correct scaling of subscripts

            begin{document}

            newcommand*subtxt[1]{_{textnormal{#1}}}
            DeclareRobustCommand_{ifmmodeexpandaftersubtxtelsetextunderscorefi}

            [
            X_i + Xsubtxt{i} + X_i + X_{text goes here}
            ]

            end{document}


            output



            Notes:




            • I'm using textnormal instead of text because the font of subscripts created with the latter command changes based on the surrounding text. You for instance probably wouldn't want all of your subscripts inside theorem environments to be in italics. See e.g. this answer for more info.


            • I'm using DeclareRobustCommand to redefine _ because the original version of this macro is also defined like that. It isn't too important, but more information can be found here.



            Unless you're using underscores for some other purpose in your document, you can now do a search-and-replace to change every _ into _.







            share|improve this answer














            share|improve this answer



            share|improve this answer








            edited Dec 18 '18 at 22:41

























            answered Dec 18 '18 at 20:43









            Circumscribe

            4,6811432




            4,6811432























                5














                enter image description here



                documentclass{article}

                begin{document}
                sbox0{$$}

                scriptfont1=scriptfont0


                $X_{abc}+y_{max}$


                end{document}


                Note this affects all math uses of the script size font not just subscripts.






                share|improve this answer





















                • Would that work for equation, align and other environments?
                  – Andy Grey
                  Dec 18 '18 at 19:22










                • @AndyGrey yes..
                  – David Carlisle
                  Dec 18 '18 at 19:24






                • 2




                  What kind of sorcery is sbox0{$$} for? Just loading the math fonts?
                  – Werner
                  Dec 18 '18 at 21:35






                • 1




                  @Werner latex delays finalizing the math setup until the first use of math at each font size, so that you can switch math fonts. actually for basic math at normalsize it probably makes no difference as things are pre-loaded, but it's a good habit to make sure...
                  – David Carlisle
                  Dec 18 '18 at 21:48








                • 1




                  $x_{max}$ worksfootnote{But $X_{max}$ doesn't} and what about $x_{max}$?
                  – egreg
                  Dec 18 '18 at 22:32
















                5














                enter image description here



                documentclass{article}

                begin{document}
                sbox0{$$}

                scriptfont1=scriptfont0


                $X_{abc}+y_{max}$


                end{document}


                Note this affects all math uses of the script size font not just subscripts.






                share|improve this answer





















                • Would that work for equation, align and other environments?
                  – Andy Grey
                  Dec 18 '18 at 19:22










                • @AndyGrey yes..
                  – David Carlisle
                  Dec 18 '18 at 19:24






                • 2




                  What kind of sorcery is sbox0{$$} for? Just loading the math fonts?
                  – Werner
                  Dec 18 '18 at 21:35






                • 1




                  @Werner latex delays finalizing the math setup until the first use of math at each font size, so that you can switch math fonts. actually for basic math at normalsize it probably makes no difference as things are pre-loaded, but it's a good habit to make sure...
                  – David Carlisle
                  Dec 18 '18 at 21:48








                • 1




                  $x_{max}$ worksfootnote{But $X_{max}$ doesn't} and what about $x_{max}$?
                  – egreg
                  Dec 18 '18 at 22:32














                5












                5








                5






                enter image description here



                documentclass{article}

                begin{document}
                sbox0{$$}

                scriptfont1=scriptfont0


                $X_{abc}+y_{max}$


                end{document}


                Note this affects all math uses of the script size font not just subscripts.






                share|improve this answer












                enter image description here



                documentclass{article}

                begin{document}
                sbox0{$$}

                scriptfont1=scriptfont0


                $X_{abc}+y_{max}$


                end{document}


                Note this affects all math uses of the script size font not just subscripts.







                share|improve this answer












                share|improve this answer



                share|improve this answer










                answered Dec 18 '18 at 19:20









                David Carlisle

                482k3811141852




                482k3811141852












                • Would that work for equation, align and other environments?
                  – Andy Grey
                  Dec 18 '18 at 19:22










                • @AndyGrey yes..
                  – David Carlisle
                  Dec 18 '18 at 19:24






                • 2




                  What kind of sorcery is sbox0{$$} for? Just loading the math fonts?
                  – Werner
                  Dec 18 '18 at 21:35






                • 1




                  @Werner latex delays finalizing the math setup until the first use of math at each font size, so that you can switch math fonts. actually for basic math at normalsize it probably makes no difference as things are pre-loaded, but it's a good habit to make sure...
                  – David Carlisle
                  Dec 18 '18 at 21:48








                • 1




                  $x_{max}$ worksfootnote{But $X_{max}$ doesn't} and what about $x_{max}$?
                  – egreg
                  Dec 18 '18 at 22:32


















                • Would that work for equation, align and other environments?
                  – Andy Grey
                  Dec 18 '18 at 19:22










                • @AndyGrey yes..
                  – David Carlisle
                  Dec 18 '18 at 19:24






                • 2




                  What kind of sorcery is sbox0{$$} for? Just loading the math fonts?
                  – Werner
                  Dec 18 '18 at 21:35






                • 1




                  @Werner latex delays finalizing the math setup until the first use of math at each font size, so that you can switch math fonts. actually for basic math at normalsize it probably makes no difference as things are pre-loaded, but it's a good habit to make sure...
                  – David Carlisle
                  Dec 18 '18 at 21:48








                • 1




                  $x_{max}$ worksfootnote{But $X_{max}$ doesn't} and what about $x_{max}$?
                  – egreg
                  Dec 18 '18 at 22:32
















                Would that work for equation, align and other environments?
                – Andy Grey
                Dec 18 '18 at 19:22




                Would that work for equation, align and other environments?
                – Andy Grey
                Dec 18 '18 at 19:22












                @AndyGrey yes..
                – David Carlisle
                Dec 18 '18 at 19:24




                @AndyGrey yes..
                – David Carlisle
                Dec 18 '18 at 19:24




                2




                2




                What kind of sorcery is sbox0{$$} for? Just loading the math fonts?
                – Werner
                Dec 18 '18 at 21:35




                What kind of sorcery is sbox0{$$} for? Just loading the math fonts?
                – Werner
                Dec 18 '18 at 21:35




                1




                1




                @Werner latex delays finalizing the math setup until the first use of math at each font size, so that you can switch math fonts. actually for basic math at normalsize it probably makes no difference as things are pre-loaded, but it's a good habit to make sure...
                – David Carlisle
                Dec 18 '18 at 21:48






                @Werner latex delays finalizing the math setup until the first use of math at each font size, so that you can switch math fonts. actually for basic math at normalsize it probably makes no difference as things are pre-loaded, but it's a good habit to make sure...
                – David Carlisle
                Dec 18 '18 at 21:48






                1




                1




                $x_{max}$ worksfootnote{But $X_{max}$ doesn't} and what about $x_{max}$?
                – egreg
                Dec 18 '18 at 22:32




                $x_{max}$ worksfootnote{But $X_{max}$ doesn't} and what about $x_{max}$?
                – egreg
                Dec 18 '18 at 22:32











                5














                Here's a LuaLaTeX-based solution. Subscripts enclosed by curly braces are typeset with upright ("roman") letters, as long as there's no space between the _ (underscore) character and the material enclosed in curly braces. If a subscript term is not enclosed in curly braces, e.g., $x_i$, it's not processed by the Lua code.



                If, for some reason, you do not want to the Lua function to operate on a subscript term encased in curly braces, just make sure that there are one or more spaces between _ and the subscript term. An obvious reason for wanting to suspend operation of the Lua function would be the fact that the subscript term contains math material which should be processed in math mode.



                To activate operations, issue the instruction upsubOn. To terminate them completely, execute upsubOff.



                enter image description here



                % !TEX TS-program = lualatex
                documentclass{article}

                usepackage{amsmath,unicode-math}
                usepackage{luacode}
                %% Lua-side code:
                begin{luacode}


                function sub_up ( s )
                return ( s:gsub ( "_(%b{})" , "_{\textnormal%1}" ) )
                end


                end{luacode}
                %% LaTeX-side code:
                newcommandupsubOn{directlua{luatexbase.add_to_callback(
                "process_input_buffer" , sub_up , "subup" )}}
                newcommandupsubOff{directlua{luatexbase.remove_from_callback(
                "process_input_buffer" , "subup" )}}
                AtBeginDocument{upsubOn} % activate the Lua function by default

                begin{document}
                $X_{text goes here}$quad $x_ {ab cd}$quad $x_ {i_j},x_k^u$

                upsubOff
                $X_{text goes here}$quad $x_ {ab cd}$quad $x_ {i_j},x_k^u$
                end{document}





                share|improve this answer


























                  5














                  Here's a LuaLaTeX-based solution. Subscripts enclosed by curly braces are typeset with upright ("roman") letters, as long as there's no space between the _ (underscore) character and the material enclosed in curly braces. If a subscript term is not enclosed in curly braces, e.g., $x_i$, it's not processed by the Lua code.



                  If, for some reason, you do not want to the Lua function to operate on a subscript term encased in curly braces, just make sure that there are one or more spaces between _ and the subscript term. An obvious reason for wanting to suspend operation of the Lua function would be the fact that the subscript term contains math material which should be processed in math mode.



                  To activate operations, issue the instruction upsubOn. To terminate them completely, execute upsubOff.



                  enter image description here



                  % !TEX TS-program = lualatex
                  documentclass{article}

                  usepackage{amsmath,unicode-math}
                  usepackage{luacode}
                  %% Lua-side code:
                  begin{luacode}


                  function sub_up ( s )
                  return ( s:gsub ( "_(%b{})" , "_{\textnormal%1}" ) )
                  end


                  end{luacode}
                  %% LaTeX-side code:
                  newcommandupsubOn{directlua{luatexbase.add_to_callback(
                  "process_input_buffer" , sub_up , "subup" )}}
                  newcommandupsubOff{directlua{luatexbase.remove_from_callback(
                  "process_input_buffer" , "subup" )}}
                  AtBeginDocument{upsubOn} % activate the Lua function by default

                  begin{document}
                  $X_{text goes here}$quad $x_ {ab cd}$quad $x_ {i_j},x_k^u$

                  upsubOff
                  $X_{text goes here}$quad $x_ {ab cd}$quad $x_ {i_j},x_k^u$
                  end{document}





                  share|improve this answer
























                    5












                    5








                    5






                    Here's a LuaLaTeX-based solution. Subscripts enclosed by curly braces are typeset with upright ("roman") letters, as long as there's no space between the _ (underscore) character and the material enclosed in curly braces. If a subscript term is not enclosed in curly braces, e.g., $x_i$, it's not processed by the Lua code.



                    If, for some reason, you do not want to the Lua function to operate on a subscript term encased in curly braces, just make sure that there are one or more spaces between _ and the subscript term. An obvious reason for wanting to suspend operation of the Lua function would be the fact that the subscript term contains math material which should be processed in math mode.



                    To activate operations, issue the instruction upsubOn. To terminate them completely, execute upsubOff.



                    enter image description here



                    % !TEX TS-program = lualatex
                    documentclass{article}

                    usepackage{amsmath,unicode-math}
                    usepackage{luacode}
                    %% Lua-side code:
                    begin{luacode}


                    function sub_up ( s )
                    return ( s:gsub ( "_(%b{})" , "_{\textnormal%1}" ) )
                    end


                    end{luacode}
                    %% LaTeX-side code:
                    newcommandupsubOn{directlua{luatexbase.add_to_callback(
                    "process_input_buffer" , sub_up , "subup" )}}
                    newcommandupsubOff{directlua{luatexbase.remove_from_callback(
                    "process_input_buffer" , "subup" )}}
                    AtBeginDocument{upsubOn} % activate the Lua function by default

                    begin{document}
                    $X_{text goes here}$quad $x_ {ab cd}$quad $x_ {i_j},x_k^u$

                    upsubOff
                    $X_{text goes here}$quad $x_ {ab cd}$quad $x_ {i_j},x_k^u$
                    end{document}





                    share|improve this answer












                    Here's a LuaLaTeX-based solution. Subscripts enclosed by curly braces are typeset with upright ("roman") letters, as long as there's no space between the _ (underscore) character and the material enclosed in curly braces. If a subscript term is not enclosed in curly braces, e.g., $x_i$, it's not processed by the Lua code.



                    If, for some reason, you do not want to the Lua function to operate on a subscript term encased in curly braces, just make sure that there are one or more spaces between _ and the subscript term. An obvious reason for wanting to suspend operation of the Lua function would be the fact that the subscript term contains math material which should be processed in math mode.



                    To activate operations, issue the instruction upsubOn. To terminate them completely, execute upsubOff.



                    enter image description here



                    % !TEX TS-program = lualatex
                    documentclass{article}

                    usepackage{amsmath,unicode-math}
                    usepackage{luacode}
                    %% Lua-side code:
                    begin{luacode}


                    function sub_up ( s )
                    return ( s:gsub ( "_(%b{})" , "_{\textnormal%1}" ) )
                    end


                    end{luacode}
                    %% LaTeX-side code:
                    newcommandupsubOn{directlua{luatexbase.add_to_callback(
                    "process_input_buffer" , sub_up , "subup" )}}
                    newcommandupsubOff{directlua{luatexbase.remove_from_callback(
                    "process_input_buffer" , "subup" )}}
                    AtBeginDocument{upsubOn} % activate the Lua function by default

                    begin{document}
                    $X_{text goes here}$quad $x_ {ab cd}$quad $x_ {i_j},x_k^u$

                    upsubOff
                    $X_{text goes here}$quad $x_ {ab cd}$quad $x_ {i_j},x_k^u$
                    end{document}






                    share|improve this answer












                    share|improve this answer



                    share|improve this answer










                    answered Dec 18 '18 at 21:44









                    Mico

                    274k30370756




                    274k30370756























                        5














                        I suggest to use a different character for those subscripts. One way could be to use ? that's very rarely used in math mode. Another uses (maybe you can find a way to type it easily).



                        documentclass{article}
                        usepackage{amsmath}
                        usepackage{newunicodechar} % for using ↓

                        % the main command
                        newcommand{uprightsubscript}[1]{_{textnormal{#1}}}

                        % this sets up the use of ?
                        begingrouplccode`~=`?lowercase{endgrouplet~}uprightsubscript
                        AtBeginDocument{mathcode`?="8000 }

                        % this sets up the use of ↓
                        newunicodechar{↓}{uprightsubscript}

                        textheight=2cm % just for making a smaller picture

                        begin{document}

                        $x?{max}$ worksfootnote{Also here $x?{max}$} and again $x?{max}$?

                        $x↓{max}$ worksfootnote{Also here $x↓{max}$} and again $x↓{max}$?

                        end{document}


                        enter image description here






                        share|improve this answer


























                          5














                          I suggest to use a different character for those subscripts. One way could be to use ? that's very rarely used in math mode. Another uses (maybe you can find a way to type it easily).



                          documentclass{article}
                          usepackage{amsmath}
                          usepackage{newunicodechar} % for using ↓

                          % the main command
                          newcommand{uprightsubscript}[1]{_{textnormal{#1}}}

                          % this sets up the use of ?
                          begingrouplccode`~=`?lowercase{endgrouplet~}uprightsubscript
                          AtBeginDocument{mathcode`?="8000 }

                          % this sets up the use of ↓
                          newunicodechar{↓}{uprightsubscript}

                          textheight=2cm % just for making a smaller picture

                          begin{document}

                          $x?{max}$ worksfootnote{Also here $x?{max}$} and again $x?{max}$?

                          $x↓{max}$ worksfootnote{Also here $x↓{max}$} and again $x↓{max}$?

                          end{document}


                          enter image description here






                          share|improve this answer
























                            5












                            5








                            5






                            I suggest to use a different character for those subscripts. One way could be to use ? that's very rarely used in math mode. Another uses (maybe you can find a way to type it easily).



                            documentclass{article}
                            usepackage{amsmath}
                            usepackage{newunicodechar} % for using ↓

                            % the main command
                            newcommand{uprightsubscript}[1]{_{textnormal{#1}}}

                            % this sets up the use of ?
                            begingrouplccode`~=`?lowercase{endgrouplet~}uprightsubscript
                            AtBeginDocument{mathcode`?="8000 }

                            % this sets up the use of ↓
                            newunicodechar{↓}{uprightsubscript}

                            textheight=2cm % just for making a smaller picture

                            begin{document}

                            $x?{max}$ worksfootnote{Also here $x?{max}$} and again $x?{max}$?

                            $x↓{max}$ worksfootnote{Also here $x↓{max}$} and again $x↓{max}$?

                            end{document}


                            enter image description here






                            share|improve this answer












                            I suggest to use a different character for those subscripts. One way could be to use ? that's very rarely used in math mode. Another uses (maybe you can find a way to type it easily).



                            documentclass{article}
                            usepackage{amsmath}
                            usepackage{newunicodechar} % for using ↓

                            % the main command
                            newcommand{uprightsubscript}[1]{_{textnormal{#1}}}

                            % this sets up the use of ?
                            begingrouplccode`~=`?lowercase{endgrouplet~}uprightsubscript
                            AtBeginDocument{mathcode`?="8000 }

                            % this sets up the use of ↓
                            newunicodechar{↓}{uprightsubscript}

                            textheight=2cm % just for making a smaller picture

                            begin{document}

                            $x?{max}$ worksfootnote{Also here $x?{max}$} and again $x?{max}$?

                            $x↓{max}$ worksfootnote{Also here $x↓{max}$} and again $x↓{max}$?

                            end{document}


                            enter image description here







                            share|improve this answer












                            share|improve this answer



                            share|improve this answer










                            answered Dec 18 '18 at 22:53









                            egreg

                            709k8618823165




                            709k8618823165






























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