Undesirable highlighting of a keyword name (dh) occuring within an identifier (0dh)

Question

I'm using the x86masm dialect of Assembler and register names are emphasized even when they occur inside of a label or a hexadecimal number. For example, dh is register, but 0dh is a number, yet the dh part of it is emphasized. I haven't had this problem in listings with any other languages, so I'm assuming it's a problem with the language definition. Is there simple way to redefine the language so that this doesn't happen?

enter image description here

\documentclass[12pt]{article}
\usepackage{courier, listings}

\lstset{
  language={[x86masm]Assembler},
  basicstyle=\ttfamily\small,
  frame=single
}

\begin{document}
\begin{lstlisting}
cmp al, 0dh ; dh = register, 0dh = number
je somewhere
\end{lstlisting}

\end{document}

score 1 · Answer 1 · answered Sep 14 '11 at 14:16

1

use deletekeywords=.... However, you should use another monotypefont like beramono. Courier is not a good looking mono font.

\documentclass[12pt]{article}
\usepackage{courier, listings}

\lstset{
  language={[x86masm]Assembler},
  basicstyle=\ttfamily\small,
  frame=single,
  deletekeywords={dh}
}

\begin{document}
\begin{lstlisting}
cmp al, 0dh ; dh = register, 0dh = number
je somewhere
\end{lstlisting}

\end{document}

answered Sep 14 '11 at 14:16

I might still use the dh register somewhere else, and I'd want it emphasized there. Also, this happens with a lot of other registers (bh, ah, ch), and labels are even more likely to have mnemonics in them, so I might as well remove all highlighting if I'm gonna do it this way. – Adrian Sep 14 '11 at 14:26
@Adrian: Where is the problem? Then change it only locally! \begin{lstlisting}[deletekeywords={dh}] – Sep 14 '11 at 15:29
2

@Herbert: I think the problem is that the OP wants the register dh highlighted, but does not want it highlighted in the number 0dh. Seems that to get a complete general solution, the package would be required to parse the actual language to do that as opposed to just match keywords. – Peter Grill Sep 14 '11 at 16:15
1

I did some more tests, and this is a listings problem, not just a problem with the language definition. It only happens with literals starting with digits, ending in a keyword, and containing no other letters. This problem is much more likely to occur in assembly than in other languages because of the short mnemonic names and ubiquity of hexadecimal numbers. – Adrian Sep 14 '11 at 16:40
4

Okay, I was able to solve this by turning on case sensitivity and making all hexadecimal digits uppercase. – Adrian Sep 14 '11 at 16:50
3

@Adrian: Your last two comments might be worth to be given as an answer: They give some more hints about the root of the problem and provide a reasonable workaround. (Note that it is perfectly acceptable to answer your own questions, other members might profit from your solution!) – Daniel Sep 14 '11 at 19:25
@Adrian I'm experiencing a similiar problem with ABAP where there are a lot of keywords. Your solution with case sensitivty seems to be a good workaround. It would have been nice to have had this as an answer. – Benjamin Sep 27 '16 at 10:58

score 0 · Answer 2 · edited Apr 13 '17 at 12:35

By default, listings treats sequences of digits (and other characters) and sequences of letters separately. More specifically here, listings recognises the digit 0 and prints it out, and then recognises the keyword dh (defined by the x86masm language) and highlights it as such.

As Herbert wrote in his answer, you can of course delete dh from the list of keywords, like so

deletekeywords={dh}

However, that approach is less than ideal, because it completely prevents any instance of identifier dh from being highlighted, as shown in the screenshot below.

enter image description here

A preferable approach is to tell listings to treat digits and letters together, not separately, by making digits "letters":

alsoletter=0123456789,

Then, listings will treat 0dh as a single entity; dh will get highlighted, but 0dh won't, as desired.

enter image description here

Complete code

\documentclass[12pt]{article}
\usepackage{courier, listings}

\lstset{
  language={[x86masm]Assembler},
% deletekeywords={dh},    % less than ideal
  alsoletter=0123456789,  % better 
  basicstyle=\ttfamily\small,
  frame=single,
}

\begin{document}
\begin{lstlisting}
cmp al, 0dh ; dh = register, 0dh = number
je somewhere
--- TestTestTest: dh ---
\end{lstlisting}

\end{document}

Undesirable highlighting of a keyword name (dh) occuring within an identifier (0dh)

2 Answers2

Complete code

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