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I'm using the Songs latex package. I'm currently defining the guitar fret diagrams of a chord for each song, but I'd like to define them in an external file to include them in each song (in order to not repeat myself).

How can I do this?

The diagrams and the command \gtab are explained here: http://songs.sourceforge.net/songsdoc/songs.html#sec6

but I couldn't find any useful info.

fedelibre
  • 141
  • 4

1 Answers1

2

I understand that you want to create a "database" of tabs diagrams.

You could create a database with two columns, the first for the names of the chords and the second for the tab description (they will become the first and the second arguments of \gtab command).

\begin{filecontents*}{tabs.txt}
A,X02220:001230
C#sus4,4:XX3341
B&,X13331
\end{filecontents*}

\documentclass{book}
\usepackage{xparse}
\usepackage{songs}
\ExplSyntaxOn
\ior_new:N \g_fedelibre_get_tabs_ior
\prop_new:N \g_fedelibre_tabs_prop

\cs_new_protected:Npn \fedelibre_add_to_prop:w #1,#2!!
 {
  \prop_gput:Nnn \g_fedelibre_tabs_prop {#1} {#2}
 }
\ior_open:Nn \g_fedelibre_get_tabs_ior {tabs.txt} 
\ior_str_map_inline:Nn \g_fedelibre_get_tabs_ior
 {
  \fedelibre_add_to_prop:w #1!!
 } 
\DeclareDocumentCommand{ \fedetab }{ v }
 {
  \prop_get:NnNTF \g_fedelibre_tabs_prop {#1} \l_tmpa_tl
   {
    \fedelibre_gtab:nV {#1} \l_tmpa_tl
   }
   {
    \msg_term:n {Maybe~ you~ have~ mispelled~ your~ tab!}
   }
 }
\cs_set_eq:NN \fedelibre_gtab:nn \gtab
\cs_generate_variant:Nn \fedelibre_gtab:nn { nV }
\ExplSyntaxOff
\begin{document}
\begin{songs}{}
\beginsong{Song}
\beginverse
\fedetab{A}  \fedetab{C#sus4} \fedetab{B&}
 \[C]  \[D]  \[C] 
\endverse
\endsong
\end{songs}
\end{document}

This code reads your databased and stores your entries in a property list. With the \fedetab{something} command you print the tab for the something chord. If that chord name does not exist, you receive a message.

Thanks to @egreg for having solved an expansion problem that made the code useless.

Francesco Endrici
  • 430