vrt2tei.pl

#! /usr/bin/perl -w


###########################################################################################################################################################
# vrt2tei.pl
# eureco
# leibniz-institut fuer deutsche sprache / csc finland esbo
# august 2024
# 
# 
# using XML::Twig , see http://www.xmltwig.org/, https://metacpan.org/pod/XML::Twiga
# 
# usage: see below the usage fugnction
# Usage:  ./vrt2tei.pl <vrtxmlfile.xml> <outfile>
#         <vrtxmlfile>: xml-ised vrt file
#
#
# TODO: 
# 1  insert dtd spec, or ref to TEI

# 3a remove the vrt positional attribute comment line / all comment lines
# 3b add @head and @deprel to I5 sowie auch @msd
# 3c bearbeitung von @head und @deprel in tei2korapxml durch Nils?
# 3d build 30 billion corpus

# 4a take care of IDs
# 4b see to the values of @xml:lang
# 5 abfangen von unerwarteten elementen dh andere als <sentence> und <paragraph>
# 5a wort reihenfolge nochmal checken
# 6 checks and balances
# 7  How to encode Kielipankki and National Library of Finland? in teiCorpus Header
# 8  construct <idsDoc>s for the months (or go for TEI)
# 9  parallelisation in bash and application on sub corpora of KLK
# 10  re-implementation of the gawk code in the perl script
# 12  re-implement creation of text header from xml file in another twig / parametrize TEI vs I5



#remember
#formatted.xml:105613: element w: validity error : No declaration for attribute deprel of element w
#formatted.xml:105613: element w: validity error : No declaration for attribute head of element w


#
#
############################################################################################################################################################


use strict;
use warnings;

use XML::Twig; 
use XML::Generator ':pretty';  # apparently no effect when using flush();

 
use locale;                 # diese drei Zeilen, damit \b im regex nicht Umlaute und ß matcht.
use POSIX qw(locale_h);     # to be able to use setlocale()
#setlocale(LC_ALL,'de_DE');  
setlocale(LC_ALL, "fi_FI");  
use utf8;
use open qw( :std :encoding(UTF-8) );

use Time::Piece;
use Tie::IxHash;



#----------------------
# check file arguments:
#----------------------

# arg0 infile:   vrt-xml

unless($ARGV[0]) {&usage_message()} ; # min arg0, the input file
if    ($ARGV[1]) {&usage_message()};  # max arg0, the input file


####################
# GLOBAL VARIABLES 
####################

my $encoding = "UTF-8";               
#my $encoding = "iso-8859-1";             # dieses $encoding ist NUR fuer das output s.u. twig funktion
my $textcounter = 0;

my %doccounter = (                        # by the month as in derekox
    "01" => 1,
    "02" => 1,
    "03" => 1,
    "04" => 1,
    "05" => 1,
    "06" => 1,
    "07" => 1,
    "08" => 1,
    "09" => 1,
    "10" => 1,
    "11" => 1,
    "12" => 1,
    );


my $sourcescsvfile = "sources_klk_fi_v2_2021_4eureco.csv";
my $corpheaderfile = "teiCorpusHeaderSkeleton.tei.xml";
my $textheaderfile = "teiTextHeaderSkeleton.tei.xml";


my $twig="";   
my $teiCorpusHeaderDoc="";

# global variables pertaining to the original corpus :
my $kielipankkiCorpus = "klk-fi-v2-vrt";

my %months = (
     "01" => "JAN",
     "02" => "FEB",
     "03" => "MAR",
     "04" => "APR",
     "05" => "MAY",
     "06" => "JUN",
     "07" => "JUL",
     "08" => "AUG",
     "09" => "SEP",
     "10" => "OCT",
     "11" => "NOV",
     "12" => "DEC",
     );

#------------------------------------------------------------------
# read corpusHeaderSkeleton document and get header out of it
#------------------------------------------------------------------

my $teiCorpusHeaderDocTwig = new XML::Twig(
    keep_spaces => 1,
    keep_atts_order => 1,
    comments => 'drop',
    );


$teiCorpusHeaderDocTwig->parsefile($corpheaderfile);
my $corpusHeader = $teiCorpusHeaderDocTwig->root;                  # getting the teiHeader for corpus out of the teiCorpusHeaderSkeleton document


#------------------------------------------------------------------
# read textHeaderSkeleton document adn get header out of it
#------------------------------------------------------------------

my $teiTextHeaderDocTwig = new XML::Twig(
    keep_spaces => 1,
    keep_atts_order => 1,
    comments => 'drop',
    );

$teiTextHeaderDocTwig->parsefile($textheaderfile);
my $textHeader = $teiTextHeaderDocTwig->root;                      # getting the teiHeader for corpus out of the teiTextHeaderSkeleton document


#----------------------------------
# read input VRT-XML document
#----------------------------------

open(my $IN,  "< $ARGV[0]") || die("$0: cannot open file for reading: $ARGV[0]");     # open input  file and initialise filehandel, actually does not seem to be needed
                                                                                      # as parsefile() (s.b.) is applied to the filename

#-------------------------------------------------------------------------------------------
# read source metadata file (prepared manually => ultimately read the info from CMDI File?)
#-------------------------------------------------------------------------------------------

my $linecount=0;
open(my $SOURCES, $sourcescsvfile) || die("$0: cannot open file for reading: $sourcescsvfile");
while(my $line = $SOURCES){
    $linecount++;
    chomp($line);
    if ( $line=~/^\#/  ||  $line=~/^\s*$/ || $linecount == 1){  # skip line if emmpty line or comment line or first line
	next;
    };
    # split each line into array:
    my @line = split(/\t+/, $line);
    
    # $sources{"Suomen Kuvalehti"}[0]

}

# while (my $line = <$seq_fh>) {
#    chomp $line;
#    ## skip comments and blank lines and optional repeat of title line
#    next if $line =~ /^\#/ || $line =~ /^\s*$/ || $line =~ /^\+/;
#    #split each line into array
#    my @line = split(/\s+/, $line);
#    $result{$line[0]}{yeartotal} += $line[1];
#    $result{$line[0]}{earning} += $line[3] - $line[2];
# }

    



#####################
#     M A I N  
#####################

#-------------------------------------------------------------------------------------------------------------
# start twig for input and call start tag handler for root and twig handler for each <text> in the VRT
#-------------------------------------------------------------------------------------------------------------


$twig = new XML::Twig(
    keep_spaces => 1,           # dadurch auch whitespaces an ehemeligen elementgrenzen im output
    keep_atts_order => 1,       # requires Tie::IxHash
    comments => 'drop',
    start_tag_handlers => {
	texts => sub{root(@_, $corpusHeader)}
    },
    twig_handlers =>  {
#	text => \&text
	text =>  sub{text(@_, $textHeader->copy)}    #   copy must be because textHeader will be flushed with $twig in the <text> handler;
    },
    # dtd_handlers =>   {       # ToDo for I5
    #	\&set_dtd;
    # }
    
    output_encoding => $encoding,
    );

$twig->parsefile($ARGV[0]);





###########
# END MAIN
###########




##############################
#   S U B R O U T I N E S
##############################

# sub set_dtd [
#    my $twig, $dtd = @_;
#    my $internal = qq|\nPUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"\n"DTD/xhtml1-strict.dtd"|;
#
#    $twig->twig_doctype('html', undef, undef, $internal);
#    }



sub root {
    my ($twig, $root, $corpusHeader) =@_;

    $root->set_gi('teiCorpus');
    $root->set_att("xmlns", 'http://www.tei-c.org/ns/1.0');

    &insertCorpusHeader($root, $corpusHeader);
}



sub insertCorpusHeader{
    my ($root, $corpusHeader) =@_;

    #---------------------------------------------------------------------------
    # get some metadata for the current output corpus based on source and year
    #---------------------------------------------------------------------------
    
    my @array = split(/\//, $ARGV[0]);
    my $l = scalar(@array);
    my $source = $array[$l-1];
    $source =~ s/([0-9][0-9][0-9][0-9])\.xml$//;

    my $language="Finnish";
    my $lang_tla="fi";
    
    my $year = $1;   # $1 now containts substring in first bracket in regex above

    my $ctitle = $source . " " . $year . ", from ". $kielipankkiCorpus . " for EuReCo";    # to do: also get name of corpus (klk-fi-v2-vrt)


    #-----------------------
    # set corpus header
    #-----------------------
    
    &set_title(     $corpusHeader, $source, $year, $kielipankkiCorpus);
    &set_sourceDesc($corpusHeader, $source, $year, $kielipankkiCorpus);

    my $teiCorpusHeader        = $corpusHeader->paste("first_child", $root);

}
    

#----------------------------
# handler &text for <text>
#----------------------------

sub text {
    my ($twig, $text, $textHeader) = @_;

    $textcounter++;               

    
    # ToDo: catch all other, unexpected children of root

    #--------------------------------------------------------------------------
    # Get text metadata (attributes of <text>) and create teiHeader for <text>
    #--------------------------------------------------------------------------
    
    my $textattsref = $text->atts();               # $textattsref is now a reference to a hash and should be used with '->'

    # &createTextHeader returns the $textID:
    my $textID = &createTextHeader($text, $textattsref, $textHeader);
    
    #--------------------------
    # create <TEI> from <text>
    #--------------------------
    
    # set vrt <text> to <TEI> and delete all attributes after they were were saved above
    $text->del_atts;
    $text->set_gi("TEI");
    $text->set_att('xml:id', $textID);
    

      

    
    
    #------------------------------------------------------------------
    # create the <tei:text>, <body>, <div> elements inside <TEI>
    #------------------------------------------------------------------
    
    my $ttext_element = XML::Twig::Elt->new('text');
    my $body_element  = XML::Twig::Elt->new('body');
    my $div_element   = XML::Twig::Elt->new('div');

    # set atts
    $div_element  ->set_att("type", "page");                          # ToDo: this is specific to KLK
    $ttext_element->set_att("xml:lang", 'fi');                               # as in ICC-NOR

    # paste
    $ttext_element->paste('last_child',  $text);
    $body_element ->paste('last_child',  $ttext_element);
    $div_element  ->paste('last_child',  $body_element);

    
    #-------------------------------
    # create <p> from <paragraph>
    #-------------------------------
    
    my @paragraphs = $text->children( 'paragraph');

    foreach my $paragraph (@paragraphs) {
	
	&setP($paragraph);

	$paragraph->move('last_child', $div_element);
	
	#------------------------------
	# create <s> from <sentence>
	#------------------------------
	
	my @sentences = $paragraph->children('sentence');
	foreach my $sentence (@sentences) {

	    &setS($sentence);


	    #--------------------------------------
	    # create <w> (word) from each $line
	    #--------------------------------------
	    
	    my @lines = split(/\n+/, $sentence->xml_text);
	    $sentence->set_text("\n");

	    for my $line (@lines){                                 # Todo: Reihenfolge checken
		if($line ne "" ){
		    my $w_element = XML::Twig::Elt->new('w');
		    &createW($w_element, $line);
		    $w_element->paste('last_child', $sentence);
		}
	    } # end words
	} # end sentences
    } # end paragraphs

    # $twig->set_pretty_print( 'record');
    # $twig->flush($OUT);
    $twig->flush("/dev/stdout");
}

sub createTextHeader{
    my ($text, $textattsref, $textHeader) = @_;
    
    # USE 01 binding_id="2246025"
    # USE 02 date="2021-01-15"
    #     03 datefrom="20210115"
    #     04 dateto="20210115"
    #     05 elec_date="_"
    #     06 file=""
    # USE 07 filename_metadata="finclarin_siirto_k2021/0039-5552/2021/alto/2246025_0039-5552_2021-01-15_SK0221_mets.xml"
    # USE 08 filename_orig    ="finclarin_siirto_k2021/0039-5552/2021/alto/2246025_0039-5552_2021-01-15_SK0221_page-2021011502210030301.xml
    # USE 09 id="t-bcd0f3fa-bbd3dac4"
    #     10 img_url=""
    # USE 11 issue_date="15.01.2021"
    # USE 12 issue_no="SK0221"
    # USE 13 issue_title="Suomen Kuvalehti"
    # USE 14 label="Suomen Kuvalehti no. SK0221 15.01.2021"
    # USE 16 language="fi"
    # USE 17 page_id="p1"
    # USE 18 page_no="None"
    #     19 part_name="_"
    #     20 publ_id="0039-5552"
    #     21 publ_part=""
    # USE 22 publ_title="Suomen Kuvalehti" 
    # USE 23 publ_type="aikakausi"
    # USE 24 sentcount="70"
    # USE 25 sum_lang="|xxx:44|fin:23|eng:3|"
    #     26 timefrom="000000"
    #     27 timeto="235959"
    # USE 28 tokencount="304"
    #     29 version_added="KLK-fi-2021">


    my $BID          = $textattsref->{'binding_id'};
    my $DATE         = $textattsref->{'date'};
    my $METAFILENAME = $textattsref->{'filename_metadata'};    
    my $ORIGFILENAME = $textattsref->{'filename_orig'};
    my $ID           = $textattsref->{'id'};
    my $ISSUEDATE    = $textattsref->{'issue_date'};
    my $ISSUENO      = $textattsref->{'issue_no'};
    my $ISSUETITLE   = $textattsref->{'issue_title'};
    my $LABEL        = $textattsref->{'label'};
    my $LANGUAGE     = $textattsref->{'language'};
    my $PAGEID       = $textattsref->{'page_id'};
    my $PAGENO       = $textattsref->{'page_no'};
    my $PUBLTITLE    = $textattsref->{'publ_title'};
    my $PUBLTYPE     = $textattsref->{'publ_type'};
    my $SENTCOUNT    = $textattsref->{'sentcount'};
    my $SUMLANG      = $textattsref->{'sum_lang'};
    my $TOKENCOUNT   = $textattsref->{'tokencount'};

    
    #-----------------------------
    # Derived Metadata variables
    #-----------------------------

    my @datearray = split("-", $DATE);
    my @langarray = split("|", $SUMLANG);
    my @namearray = split(/[\.\/]/, $ORIGFILENAME);  # use $namearray[4] as ID for the page
    


    #----------------------------------------------------
    # create textSigle to be returned from this function
    #----------------------------------------------------

    # SUK21.JAN.00001
    
    my $corpusID = "SUK";                            # ToDo read Table with Source metadata
    my $yy       = substr($datearray[0], 2, 2);      # substr EXPR,OFFSET,LENGTH
    my $mm       = $datearray[1];                    # substr EXPR,OFFSET,LENGTH
    my $MMM      = $months{$mm};

    my $textID = $corpusID . $yy . "_" . $MMM . "." . sprintf("%05d", $doccounter{$mm}++);

    
    
    #-----------------------------------------------------------------------
    # CREATE text-teiHeader ACCORDING TO THE SKELETON in $textHeader
    #-----------------------------------------------------------------------


    $textHeader->paste('first_child', $text);

    #-----------------------------------------------
    # <teiHeader>
    #   <fileDesc n="EuReCo-KLK-FIN_[$ID]">
    #     <titleStmt>
    #       <title>[$LABEL, page $PAGENO]</title>	

    $textHeader->first_child("fileDesc")   ->  set_att('n', "EuReCo-". $kielipankkiCorpus . $ID);
    
    $textHeader->first_child("fileDesc")    -> first_child("titleStmt")->first_child("title")
	->set_text($LABEL . ", Text #" . $textcounter);    # Case KLK;  PAGENO scheint meist "None" zu sein

    #-----------------------------------------------
    # <fileDesc>
    #  <sourceDesc>
    #   <biblStruct>
    #      <analytic>
    #         <title type="main">[$LABEL, page $PAGENO]</title>
    #         <date>[$DATE]</date>
    #         <date type="year">TODO</date>
    #         <date type="month">TODO</date>
    #         <date type="day">TODO</date>
    #         <idno type="PAGEID">$PAGEID</idno>
    #         <idno type="BINDINGID">$BID</idno>
    #         <idno type="ID">$ID</idno>
    #         <idno type="KIELIPANKKI_METAFILENAME">$METAFILENAME</idno>
    #         <idno type="KIELIPANKKI_ORIGFILENAME">$ORIGFILENAME</idno>
    #         <textLang>$LANGUAGE</textLang>

    my $analytic  = $textHeader->get_xpath("./fileDesc/sourceDesc/biblStruct/analytic", 0);

    $analytic->first_child("title")                    ->set_text($LABEL . ", Text #" . $textcounter);   # Case KLK; PAGENO scheint meist "None" zu sein
    $analytic->get_xpath('./date[@type="date"]',   0)  ->set_text($DATE);
    $analytic->get_xpath('./date[@type="year"]',   0)  ->set_text($datearray[0]);
    $analytic->get_xpath('./date[@type="month"]',  0)  ->set_text($datearray[1]);
    $analytic->get_xpath('./date[@type="day"]',    0)  ->set_text($datearray[2]);    
    $analytic->get_xpath('./idno[@type="PAGEID"]',       0)     ->set_text($PAGEID);
    $analytic->get_xpath('./idno[@type="BINDINGID"]',    0)     ->set_text($BID);
    $analytic->get_xpath('./idno[@type="ID"]',           0)     ->set_text($ID);
    $analytic->get_xpath('./idno[@type="KIELIPANKKI_METAFILENAME"]', 0)     ->set_text($METAFILENAME);
    $analytic->get_xpath('./idno[@type="KIELIPANKKI_ORIGFILENAME"]', 0)     ->set_text($ORIGFILENAME);
    $analytic->first_child('textLang')                        ->set_text($LANGUAGE);
    
    #  <monogr>
    #    <title>$PUBLTITLE</title>
    #    <imprint>
    #      <pubPlace>TODO</pubPlace>
    #      <publisher>TODO</publisher>
    #    </imprint>
    #    <biblScope unit="ISSUETITLE"/>
    #    <biblScope unit="ISSUENO"/>
    #    <biblScope unit="ISSUEDATE"/>
    #    <biblScope unit="pp">$PAGENO</biblScope>

    my $monogr  = $textHeader->get_xpath("./fileDesc/sourceDesc/biblStruct/monogr", 0);

    $monogr->first_child("title")                                   ->set_text($PUBLTITLE);
    $monogr->first_child("imprint")->first_child("pubPlace")        ->set_text("ToDo");         # imprint is needed for tei validity
    $monogr->first_child("imprint")->first_child("publisher")       ->set_text("ToDo");         # imprint is needed for tei validity
    $monogr->get_xpath('./biblScope[@unit="ISSUETITLE"]', 0)        ->set_text($ISSUETITLE);
    $monogr->get_xpath('./biblScope[@unit="ISSUENO"]', 0)           ->set_text($ISSUENO);
    $monogr->get_xpath('./biblScope[@unit="ISSUEDATE"]', 0)         ->set_text($ISSUEDATE);
    $monogr->get_xpath('./biblScope[@unit="pp"]', 0)                ->set_text($PAGENO);        # Achtung - PAGENO scheint meist "None" zu sein

    #  <encodingDesc>
    #    <tagsDecl>
    #      <namespace name="http://www.tei-c.org/ns/1.0">
    #        <tagUsage gi="s" occurs="SENTCOUNT"/>
    #        <tagUsage gi="w" occurs="TOKENCOUNT"/>

    $textHeader->get_xpath('./encodingDesc/tagsDecl/namespace/tagUsage[@gi="s"]', 0)      -> set_att('occurs', $SENTCOUNT);
    $textHeader->get_xpath('./encodingDesc/tagsDecl/namespace/tagUsage[@gi="w"]', 0)      -> set_att('occurs', $TOKENCOUNT);
	
    #  <profileDesc>
    #    <langUsage>
    #     <language ident="fi" usage="|xxx:44|fin:23|eng:3|"/>
    #   </langUsage>
    #    <textClass>
    #      <classCode scheme="kielipankki_klk">$PUBLTYPE</classCode>
    #      <classCode scheme="kielipankki_klk_mapped">TODO</classCode>

    $textHeader->get_xpath('./profileDesc/langUsage/language', 0)                                   ->set_att('ident', $LANGUAGE);
    $textHeader->get_xpath('./profileDesc/langUsage/language', 0)                                   ->set_att('usage', $SUMLANG);
    # in @usage muss eigt. ein integer; am besten inhalt von SUMLANG aufdroeseln und mehrere <language> machen

    $textHeader->get_xpath('./profileDesc/textClass/classCode[@scheme="kielipankki_klk"]', 0)       ->set_text($PUBLTYPE);
    $textHeader->get_xpath('./profileDesc/textClass/classCode[@scheme="kielipankki_klk_mapped"]', 0)->set_text("ToDo");

    #  <revisionDesc>
    #    <change when="TODO" who="HL">TEI version for EuReCo</change>

    $textHeader->get_xpath('./revisionDesc/change', 0)                                    ->set_att('when', localtime->ymd('-'));
    
    return $textID;

    
    #-----------------------------------
    # END OF CREATING TEIHEADER
    #-----------------------------------
    
}

sub setP {
    my ($paragraph) = @_;
    
    $paragraph->set_gi('p');
    
    # <paragraph id="p-bcd0f3fa-bbd3dac4-815ead7a" sum_lang="|fin:1|">
    # atts of <paragraph>:
    #    @id        USE
    #    @sum_lang  USE: put in xml:lang and prefix the value with "x-" for private value
    
    $paragraph->set_att("xml:lang", "x-" . $paragraph->att("sum_lang"));
    $paragraph->del_att("sum_lang");
    # $paragraph->change_att_name('id', 'xml:id');
    $paragraph->del_att("id");              # diese id ist auch nicht eindeutig!!
}                                                                                                                                                                                       
sub setS {
    my ($sentence) = @_;
    
    $sentence->set_gi('s');
	    
    # the atts of <sentence>:
    #    USE   1 @id="s-bcd0f3fa-bbd3dac4-f7429090"
    #    USE   2 @lang="fin" -> xml:lang 
    #    ?     3 @lang_conf="0.6734853"> -> ToDo @cert ?	    
    
    # set attrs of <s>
    $sentence->set_att("xml:lang", $sentence->att("lang"));  # ToDo: convert the value / introduce a hash for lookup (input values: "fin", "xxx", ....)
    # $sentence->change_att_name('id', 'xml:id');            # nicht eindeutig
    $sentence->del_att('id');
    $sentence->del_att("lang");                         # replaced by xml:lang
    $sentence->del_att("lang_conf");                    # for the time being
    
}

sub createW {
    my ($w_element, $line) = @_;

    #---------------------------
    # Get the tags (=columns)
    #---------------------------
    
    my @tags = split(/\t/, $line);
    
    # set content of <w> i.e. the token
    $w_element->set_text($tags[0]);
    
    # vrt positional-attributes in corpus KLK:
    #  USE [0] word
    #  USE [1] ref  (id for reference of dephead)
    #  USE [2] lemma
    #  ?   [3] lemmacomp   (lemma with compound info - could go in @norm, as tag abuse?)
    #  USE [4] pos 
    #  USE [5] msd 
    #  USE [6] dephead
    #  USE [7] deprel 
    #      [8] content   (ocr-process)
    #      [9] vpos      (ocr-process)
    #     [10] ocr       (ocr-process)
    #     [11] cc        (ocr-process)
    #     [12] hyph      (ocr-process)
    #     [13] style     (ocr-process)
    #     [14] lex       (korp semantic disambiguation from G"oteborg)
    
    # set the attributes of <w>:
    $w_element->set_att("n",      $tags[1]);
    # $w_element->set_att("id",     "w_" . $namearray[4] . $sentence->att("xml:id") . "_" . $tags[1]);
    # so zusammengebaute ID ist auch nicht eindeutig...
    $w_element->del_att("id");
    $w_element->set_att("lemma",  $tags[2]);
    # $w_element->set_att("norm",   $tags[3]);  # tag abuse of @norm
    $w_element->set_att("pos",    $tags[4]);
    $w_element->set_att("msd",    $tags[5]);
#TMP    $w_element->set_att("head",   $tags[6]);
#TMP    $w_element->set_att("deprel", $tags[7]);
    
}
    

sub set_title{
    my ($corpusHeader, $source, $year, $kielipankkiCorpus) = @_;

    my $cTitleString = $source . " " . $year . ", from ". $kielipankkiCorpus . " for EuReCo";    

    #<teiHeader>
    #  <fileDesc>
    #    <titleStmt>
    #      <title>[Aamulehti2021] from [klk-fi-v2-vrt for] EuReCo</title>
    #    </titleStmt>
    #    <!-- ... -->
    #  </fileDesc>
    #</teiHeader>

    my $cTitleNode = $corpusHeader->first_child("fileDesc")->first_child("titleStmt")->first_child("title");

    $cTitleNode->set_text($cTitleString);
    
}

sub set_sourceDesc{
    my ($corpusHeader, $source, $year, $kielipankkiCorpus) = @_;

    my $cBiblString = $source . " " . $year . ", from ". $kielipankkiCorpus . " for EuReCo";    

    #<teiHeader>
    #  <fileDesc>
    #    <!-- ... -->
    #    <sourceDesc>
    #      <bibl>[Aamulehti2021] from [klk-fi-v2-vrt]</bibl>
    #    </sourceDesc>
    #    <!-- ... -->
    #  </fileDesc>
    #</teiHeader>

    my $cBiblNode = $corpusHeader->first_child("fileDesc")->first_child("sourceDesc")->first_child("bibl");

    $cBiblNode->set_text($cBiblString);    
}







#################
## usage_message
#################


sub usage_message {
    print "   Usage:  ./vrt2tei.pl <file.vrt.xml> <outfile>\n";
    print "   <file.vrt.xml> is a VRT file converted to proper XML\n";
    exit;
}