MTV

Merlyn Technique Viewer enhances the Web Techniques Perl Columns of Randal L. Schwartz (aka merlyn). On his home page he says of these articles,

"Because I'm generally busy (or lazy), I simply ran the source files through the pod2html translator so that I could put them online here. It makes them ugly sometimes, but you'll just have to live with that for now until someone comes up with a better solution."

A better solution

Code description interleaved with source code.

Code listed in a form for easy editing and saving.

This program fetches selected articles and code listings from their source locations and interleaves the code with the article, makes some navigation links, and lists the code in a textarea. An index data file of all the current web technique articles must be built and refreshed once in a while.

Here's a live demo.

Update: Now uses HTML::TableExtract to resist subtle changes in the source files.

#!perl -T
# mtv.pl - Merlyn Technique Viewer by epoptai
# 1. Interleaves source code with description.
# 2. Code listed in textarea for editing and saving.

use strict;
use CGI qw(:standard);
use LWP::Simple qw(get getstore);
use HTML::Entities;
use vars qw(%code $code $init $tmp $src $oop $wtc);
use HTML::TableExtract;
use CGI::Carp 'fatalsToBrowser';

my@oops=qw(10 13 28 38 48 55); # columns with double code listings
my$url = url();
my$dat = 'index.dat';
unless(-e $dat){$init=1}

&import_names('IN');

my$merlyn = 'http://web.stonehenge.com/merlyn/WebTechniques';

if($IN::action eq 'bindex'){&indexer}
if(($IN::action eq 'save as')or($IN::codename)){&savecode}
unless($IN::action eq 'view'){ 
print header,start_html(-title=>'MTV',-bgcolor=>'white',-text=>'black'
+),blockquote,h1('MTV'); 
print<<HTML;
Merlyn Technique Viewer enhances the <a href="http://web.stonehenge.co
+m/merlyn/WebTechniques"><i>
Web Techniques Perl Columns</i></a> of Randal L. Schwartz. On his home
+ page he says of these 
articles,<blockquote>"Because I'm generally busy (or lazy), I simply r
+an the source files through 
the pod2html translator so that I could put them online here. It makes
+ them ugly sometimes, but 
you'll just have to live with that for now until someone comes up with
+ a better solution."
</blockquote><h3>A better solution</h3>
<ol><li>Code description interleaved with source code.<li>Code listed 
+in a form for easy editing 
and saving.</ol> This script fetches selected articles and code listin
+gs from their source 
locations, modifies the contents, and displays the results. An index d
+ata file of all the current 
web technique articles must be <a href="$url?action=bindex">built</a> 
+and 
<a href="$url?action=bindex">refreshed</a> once in a while.
HTML
if($init==1){
    print qq~<p><b>Datafile not detected. <a href="$url?action=bindex"
+>Build an index.</a>~;
    }
if($init!=1){
    my%dex = ();
    my$md = (stat($dat))[9];
    open(FILE,"< $dat") or die "$!";
    my@dat = <FILE>;
    close(FILE) or die "$!";
    for(@dat){
        my($num,$desc)=split(/\t/);
        $dex{$num}=$desc
        }
    my$c=keys(%dex);
    my$cc=($c/4);
    print qq~<p>Index of $c Web Techniques columns<br><small>~;
    printf "%s updated:  %s\n", $dat, scalar localtime($md);
    print qq~</small><form><select name="getdoc" size="$cc">~;
    for(sort {$b<=>$a} keys(%dex)){
    my$val=$_;
    for(@oops){
        if($val=~$_){
            $val='00ps. '.$_;
            }
        }
        print qq~<option value="$_">$val. $dex{$_}~;
        }
print qq~</select><br><font size=-2>Note: '00ps' marks double code lis
+tings (@oops) which choke MTV.<br>They are diplayed without enhanceme
+nt.</font><br><input type="submit" name="action" value="view"></form>
+<br><p align=right><small><a href="http://perlmonks.org/index.pl?node
+=merlyn+technique+viewer">coded</a> by <a href="http://perlmonks.org/
+index.pl?node=epoptai">epoptai</a></small>~;
    }
print end_html;
exit;
}

if($IN::action eq 'view'){
$src = 'col' . $IN::getdoc . '.listing.txt';
$tmp = $^T . '.tmp';
my$col = 'col' . $IN::getdoc . '.html';
$wtc = $merlyn.'/'.$col;
my$wts = $merlyn.'/'.$src;
for(@oops){    if($IN::getdoc=~$_){$oop=1}}
if($oop==1){
    my$MTV=get($wtc);
    print header,blockquote;
    print $MTV;
    print end_html;
    exit(0);
    }
my$res;
getstore($wtc,$tmp); # had problems doing this with get
$code = get($wts) or die "$!";
unless(-e $tmp){ 
print header,start_html(-title=>"Column $IN::getdoc source code listin
+g",-bgcolor=>'white',-text=>'black'),blockquote,p("The newest columns
+ are not available online until after they appear in print in <a href
+='http://www.webtechniques.com/'>Web Techniques magazine</a>. Until t
+hen only the source code is published at <a href='http://web.stonehen
+ge.com/merlyn/WebTechniques/index.html'>Randal's site</a>. Try again 
+soon! <a href='$url'>Back to index.</a>");
encode_entities($code);
print "<pre>$code</pre>";
print end_html;
exit(0);
    }
}

open(F,"< $tmp") or die "$!";
my@col = <F>;
close(F) or die "$!";

my$MTV=();
{
open(F,"< $tmp") or die "$!";
local $/ = undef;
$MTV = <F>;
close(F) or die "$!";
}

if($IN::action eq 'view'){ unlink $tmp}

my@c=@col;

for(@col){
if($_=~/=(\d+)=/){                    # find code listing lines
    my$m=$&;                        # define hash key
    if($_=~/=1=/){$_=~s/<(.*?)>//g}    # fix =1=
    $m=~s/=(\d+)=/$1/;                # strip = = from key
    $_=~s/=(\d+)=/$1\./;            # and value
    $_=~s/^\s+//g;                    # strip leading whitespace
    $code{$m}=$_;                    # build code hash
    }
}

my$h=(keys(%code)+3);
my$form = "<form method='post'><input type='submit' name='action' valu
+e='save as'> <input type='text' name='codename' size='30' value='col$
+IN::getdoc.pl'><br><textarea cols=80 rows='$h' name='codebody'>$code<
+\/textarea></form>";

$MTV=~s/(([L,l]ines?\s(\d+))(\s(through|to|and)\s(\d+))?)/<mmm><p><mer
+lyn>$1<\/merlyn>/gi;
$MTV=~s/(<\/head>)/$1<base href="http:\/\/web\.stonehenge\.com\/merlyn
+\/WebTechniques\/">/oi;
$MTV=~s/(<BODY bgcolor=White text=Black>)/$1<blockquote>/oi;
$MTV=~s/(<H1>)<A NAME="(.*?)">(.*?)<\/A>(<\/H1>)/$1<a name="$2" href="
+$wtc">$3<\/a>$4<b>As rendered by 
<a href="http:\/\/perlmonks\.org\/index\.pl\?node=merlyn\+technique\+v
+iewer">MTV<\/a><\/b> - (<a href="$url">index<\/a>)<p>/iso;
$MTV=~s/(<H2>.*?<\/H2>)(.*?)<\/PRE>/$1$form/iso;
my@MTV=split(/<mmm>/,$MTV);

for(@MTV){
    if($_=~/^<p><merlyn>(([L,l]ines?\s(\d+))(\s(through|to|and)\s(\d+)
+)?<\/merlyn>)/i){
        my$d0=$&;
        my$d1=$3;
        my$c1=$5;
        my$d2=$6;
        if($c1=~/and/){
            $_=~s/$d0/<p><tt> $code{$d1}<\/tt><br><tt> $code{$d2}<\/tt
+><p>$d0/g;
            }
        elsif($c1=~/through|to/){
            my@total;
            while($d1 <= $d2){
                push @total, $code{$d1};
                $d1++
                }
            my$sum = join('<br>', @total);
            $_=~s/$d0/<pre>$sum<\/pre><p>$d0/g;
            }
        elsif(!$d2){
            $_=~s/$d0/<p><tt> $code{$d1}<\/tt><p>$d0/g;
            }
        }
    }
print header;
print @MTV;
print end_html;
exit;

sub indexer{
my$c;
my$z = $merlyn . '/index.html';
my$dexter = get($z);

my$te = new HTML::TableExtract( headers => [qw(Column Listing Descript
+ion)] );
$te->parse($dexter);

open (FILE,"> index.dat") or die "$!";
foreach my $ts ($te->table_states){
   foreach my $row ($ts->rows){
        chomp(@$row[0]);
        chomp(@$row[2]);
        @$row[0]=~s/col//o;
        print FILE "@$row[0]\t@$row[2]\n";
        $c++
        }
    }
close(FILE) or die "$!";
print header,start_html(-bgcolor=>'white',-text=>'black'),blockquote,p
+("$c Web Techniques columns indexed!<p><a href='$url'>Reload</a>");
exit
}

sub savecode{
open (FILE,"> $IN::codename") or die "$!";
print FILE $IN::codebody;
close(FILE) or die "$!";
print header,start_html(-bgcolor=>'white',-text=>'black'),blockquote,p
+("Code saved as <a href='$IN::codename'>$IN::codename</a> in same dir
+ as <a href='$url'>this script</a>.");
exit
}
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