%20comandos%20enumerados%20%5Ccmd1%20%5Ccmd2%20...%20etc%3F.png)
Estou escrevendo um documento que contém perguntas e respostas. Por exemplo
\question{What is 2+3?}{2+3=5}
\question{What is cheese?}{Food made from milk.}
As respostas são salvas para serem reunidas em uma seção posterior, com a diferença de que as respostas são embaralhadas para evitar espiadas. Isso significa que as perguntas devem conter referências futuras aos números das respostas. Por exemplo:
Q2.1 O que é 2+3?(Veja a resposta 104)
Q2.2 O que é queijo?(Ver resposta 57)
eu tenho istoquasetrabalhando.
O \questioncomando grava todas as respostas em um arquivo temporário e um \printtheanswerscomando posterior envia isso para um programa externo que
a. embaralha as respostas,
b. gera Latex para a seção de respostas e
c. gera um arquivo auxiliar qa.auxque define \answernumber1, \answernumber2etc para conter as referências futuras.
Esta é uma compilação de duas passagens. O qa.auxarquivo é carregado no início, se existir. O \questioncomando deve definir \answernumberNpara cada um deles o que não existe, para expandir para um placeholder.
No momento, \questionestá parcialmente definido - sempre define \answernumberNum espaço reservado:
\newcommand{\question}[2]{
\stepcounter{questionnumber}
\stepcounter{questionnumberinchapter}
% Define the placeholder for \answernumberN
\expandafter\edef\expandafter\answernumber\roman{questionnumber}{PLACEHOLDER:\arabic{questionnumber}}
% FOR DEBUGGING
DEFINING \texttt{\textbackslash answernumber\roman{questionnumber} as \{PLACEHOLDER:\arabic{questionnumber}\}}
% Write "x.y #2" to \qainpfilename
\immediate\write\qafile{\arabic{chapter}.\arabic{questionnumberinchapter} \unexpanded{#2}}
% Print the qustion to the document.
Q\arabic{chapter}.\arabic{questionnumberinchapter} #1 \emph{(See answer \expandafter\answernumber\roman{questionnumber}.)}
}
Aqui está a linha de interesse:
\expandafter\edef\expandafter\answernumber\roman{questionnumber}{PLACEHOLDER:\arabic{questionnumber}}
O problema éisso SEMPRE define \answernumberN, independentemente de estar definido no arquivo auxiliar.
Aqui está um MWE, embora você não possa compilá-lo sem o programa externo.
\documentclass[a4paper,10pt,openany]{scrbook}
\usepackage{verbatim}
% Define \bashline command
% Taken from https://gist.github.com/w495/7328b76e76aee49657e0bd7a3b46c870
\makeatletter
\newcommand{\bashline@file@name}[1]{%
/tmp/${USER}-${HOSTNAME}-\jobname-#1.tex%
}
\newread\bashline@file
\newcommand{\bashline@command@one}[2][tmp]{%
\immediate\write18{#2 > \bashline@file@name{#1}}
\openin\bashline@file=\bashline@file@name{#1}
% The group localizes the change to \endlinechar
\bgroup
\endlinechar=-1
\read\bashline@file to \localline
% Since everything in the group is local,
% we have to explicitly make the assignment global
\global\let\bashline@result\localline
\egroup
\closein\bashline@file
% Clean up after ourselves
\immediate\write18{rm \bashline@file@name{#1}}
\bashline@result
}
\newcommand{\bashline@command@many}[2][tmp]{%
\immediate\write18{#2 > \bashline@file@name{#1}}
\openin\bashline@file=\bashline@file@name{#1}
% The group localizes the change to \endlinechar
\newcount\linecnt
\bgroup
\endlinechar=-1
\loop\unless\ifeof\bashline@file
\read\bashline@file to \localline%
\localline
\newline
\repeat
\egroup
\closein\bashline@file
% Clean up after ourselves
\immediate\write18{rm \bashline@file@name{#1}}
}
\newcommand{\bashline}[2][tmp]{%
\bashline@command@one[#1]{#2}%
}
\newcommand{\bashlines}[2][tmp]{%
\bashline@command@many[#1]{#2}%
}
\makeatother
% Question-answer stuff.
\def\qainpfilename{qa.inp}
\def\qaauxfilename{qa.aux}
\def\qatexfilename{qa.tex}
\newwrite\qafile
\immediate\openout\qafile=\qainpfilename
\newcounter{questionnumber}
\newcounter{questionnumberinchapter}[chapter]
\newcommand{\question}[2]{
\stepcounter{questionnumber}
\stepcounter{questionnumberinchapter}
% Define the placeholder for \answernumberN
\expandafter\edef\expandafter\answernumber\roman{questionnumber}{PLACEHOLDER:\arabic{questionnumber}}
DEFINING \texttt{\textbackslash answernumber\roman{questionnumber} as \{PLACEHOLDER:\arabic{questionnumber}\}}
% Write "x.y #2" to \qainpfilename
\immediate\write\qafile{\arabic{chapter}.\arabic{questionnumberinchapter} \unexpanded{#2}}
% Print the qustion to the document.
Q\arabic{chapter}.\arabic{questionnumberinchapter} #1 \emph{(See answer \expandafter\answernumber\roman{questionnumber}.)}
}
\newcommand{\printtheanswers}{
\immediate\closeout\qafile
\bashline{bash bin/generate-answers.sh '\qainpfilename' '\qatexfilename' '\qaauxfilename'}
\input{\qatexfilename}
}
% Demonstrate that this will not be expanded until after qa.tex has been
% generated loaded into the document.
\def\examplething{this is expanded later}
\begin{document}
TEST
\IfFileExists{\qaauxfilename}{\input{\qaauxfilename}}{AUX DOES NOT EXIST}
\chapter{Maths}
\question{What is $1+2$?}{$1+2=3$ \examplething}
\question{What is $2\times 3$?}{$2\times 3=6$}
\chapter{Science}
\question{Name the six quarks.}{Up down, charm, strange, truth, and beauty.}
\question{How many planets orbit the Sun?}{Eight. Deal with it.}
\chapter{Answers}
\printtheanswers
\end{document}
O qa.auxarquivo gerado para este documento é
\def\answernumberi{3}% (Q1.1): $1+2=3$ \examplething
\def\answernumberii{1}% (Q1.2): $2\times 3=6$
\def\answernumberiii{4}% (Q2.1): Up down, charm, strange, truth, and beauty.
\def\answernumberiv{2}% (Q2.2): Eight. Deal with it.
Eu sei que você pode usar \providecommandvárias construções if-then, mas não consegui fazê-las funcionar quando o nome do comando é construído com \expandafter\answernumber\roman{questionnumber}. Como defino condicionalmente um comando cujo nome é construído a partir de um número como este?
Responder1
Com agradecimentos ao cfr, agora uso \labele\ref
O \questioncomando agora inclui
Q\arabic{chapter}.\arabic{questionnumberinchapter} #1 \emph{(See answer \expandafter\ref{\expandafter qanswer\arabic{questionnumber}}.)}
e o \printtheanswerscomando gera tex assim:
\item\label{qanswer123} (text of answer to the 123rd question)