A pseudocode environment allowing for mathmode and UTF-8 characters?

Question

My usual goto for writing pseudocode is the listings package, but unfortunately, I find myself writing a document in my native language (portuguese) and I need to write UTF-8 characters in pseudocode, and listings is not playing along.

Furthermore, I also need to use mathmode.

The code I'm trying to do in specific is this:

\begin{lstlisting}[mathescape=true]
Para todo $B \subseteq N$:
  Se as colunas de $A_B$ são linearmente independentes:
    Resolver o sistema $A_B x = b$.
    Se este tiver solução $x$:
      Se $x \geq 0$:
        Definir $v \in \mathbb R^n$ de modo a que $v_B = x$ e $v_{N\setminus B} = 0$
        Adicionar $v$ à lista de vértices.
\end{lstlisting}

This particular bit of code doesn't work, as I get the following error:

! Package inputenc Error: Unicode char �\expandafter (U+4F1)
(inputenc)                not set up for use with LaTeX.

(Though I do need inputenc to typeset UTF-8 characters, and as far as I can tell, it's a listings problem.)

The specific package does not matter, I'm just looking for a way to typeset pseudocode in my native language while still being able to use mathmode.

This also rules out fancyvrb and alltt, as those didn't play along with sub and superscripts.

TIA

Answer 1

Sebastiano's answer works well with UTF-8 based engines. To use with pdfLaTeX you can use \lstset{literate=...}:

\documentclass[a4paper,12pt]{article}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[portuguese]{babel}
\usepackage{amsmath,amssymb}
\usepackage{listings}

\newcommand{\R}{\mathbb R}

% taken from: https://tex.stackexchange.com/a/381647/134574
\lstset{
  keepspaces, % Apparently this works... (https://tex.stackexchange.com/a/46695/134574)
  literate=
  {á}{{\'a}}1
  {à}{{\`a}}1
  {ã}{{\~a}}1
  {é}{{\'e}}1
  {ê}{{\^e}}1
  {í}{{\'i}}1
  {ó}{{\'o}}1
  {õ}{{\~o}}1
  {ú}{{\'u}}1
  {ü}{{\"u}}1
  {ç}{{\c{c}}}1
}

\begin{document}

\begin{lstlisting}[mathescape=true]
Para todo $B \subseteq N$:
  Se as colunas de $A_B$ são linearmente independentes:
    Resolver o sistema $A_B x = b$.
    Se este tiver solução $x$:
      Se $x \geq 0$:
        Definir $v \in \R^n$ de modo a que $v_B = x$ e $v_{N\setminus B} = 0$
        Adicionar $v$ à lista de vértices.
\end{lstlisting}

\end{document}

---

About the spacing issue pointed out in the comments. It looks like there's a bug in listings which, after mathescaped text, the space after literated text disappears. I asked a question about this issue and Ulrich Diez apparently fired out what the problem was.

To fix the problem, add the following definition to your file:

\makeatletter
\def\lst@Literate#1#2#3{%
    \ifx\relax#2\@empty\else
        \lst@CArgX #1\relax\lst@CDef
            {}
            {\let\lst@next\@empty
             \lst@ifxliterate
                \lst@ifmode \let\lst@next\lst@CArgEmpty \fi
             \fi
             \ifx\lst@next\@empty
                 \ifx\lst@OutputBox\@gobble\else
                   \lst@XPrintToken \let\lst@scanmode\lst@scan@m
                   \lst@token{#2}\lst@length#3\relax
                   \lst@XPrintToken
                   % ↓ Missing switch added by Ulrich Diez to fix the spacing issue
                   \lst@whitespacefalse %!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
                 \fi
                 \let\lst@next\lst@CArgEmptyGobble
             \fi
             \lst@next}%
            \@empty
        \expandafter\lst@Literate
    \fi}
\makeatother

or, more compactly:

\usepackage{etoolbox}
\makeatletter
\patchcmd\lst@Literate
  {\lst@XPrintToken\fi}
  {\lst@XPrintToken\lst@whitespacefalse\fi}
  {}{}

Answer 2

You should compile the code with XeLaTeX. It works well with this type of coding.

\documentclass[a4paper,12pt]{article}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[portuguese]{babel}
\usepackage{amsmath,amssymb}
\usepackage{listings}
\begin{document}
Português para principiantes with formula
\[A(\lambda)=\cos \lambda + \sin \lambda\]

\begin{lstlisting}[mathescape=true]
Para todo $B \subseteq N$:
  Se as colunas de $A_B$ são linearmente independentes:
    Resolver o sistema $A_B x = b$.
    Se este tiver solução $x$:
      Se $x \geq 0$:
        Definir $v \in \mathbb R^n$ de modo a que $v_B = x$ e $v_{N\setminus B} = 0$
        Adicionar $v$ à lista de vértices.
\end{lstlisting}

\end{document}

Answer 3

Heiko Oberdiek's listingsutf8-package offers a workaround to the problem:

It enhances the syntax of the \lstinputlisting-command so that it can read files that are encoded in utf8 and internally re-encode them in some 8bit-encoding before "feeding" to the internals of the listings package.

In case the latin-1-encoding (ISO8859-1), which is an 8bit-encoding, can encode all characters needed in your pseudocode, you can probably use the filecontents*-environment from the filecontents-package for writing an utf8-encoded temporary file, and then use the \lstinputlisting-command which is enhanced by the listingsutf8-package for reading that utf8-file and internally re-encoding it in latin-1 before feeding it to the internals of the listings-package.

Instead of latin-1, as in the example below, you can use other 8bit-encodings in case they do better suit your needs.

In any case using the listingsutf8-package requires ε-TeX-extensions and the \pdffiledump-primitive from pdfTeX. In other words: No matter if run in .dvi-mode or run in .pdf-mode, you need some pdfLaTeX-engine with ε-TeX-extensions.

\documentclass[a4paper,12pt]{article}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[portuguese]{babel}
\usepackage{amsmath,amssymb}
\usepackage{listings}
\usepackage{listingsutf8}
\usepackage{filecontents}


\begin{document}

\begin{filecontents*}{tempfile.tex}
Para todo $B \subseteq N$:
  Se as colunas de $A_B$ são linearmente independentes:
    Resolver o sistema $A_B x = b$.
    Se este tiver solução $x$:
      Se $x \geq 0$:
        Definir $v \in \mathbb R^n$ de modo a que $v_B = x$ e $v_{N\setminus B} = 0$
        Adicionar $v$ à lista de vértices.
\end{filecontents*}
\lstinputlisting[mathescape=true, inputencoding=utf8/latin1]{tempfile.tex}

\end{document}