Copyright © 2022 Cameron Kaiser.
All rights reserved.
Released under the Perl Artistic License 2.0.
PeroleText is a set of two tools to convert to and from ProleText, an early text-based markup system circa 1995 that enabled HTML-like formatting encoded via trailing whitespace and certain inline sequences. This markup was generally invisible, allowing documents to appear largely as legible plain text to basic readers, but convertable into more-or-less full HTML (of the time) with a sufficiently advanced viewer.
For more information on ProleText's history and a comparison with later text markup systems like Markdown, see this blog post.
The tools allow conversion from ProleText to HTML (pt2html), and
HTML to ProleText with lossy conversion (html2pt). They are
currently supported on Perl 5.8 or better, though they may work on earlier
versions. No Perl modules are required to use them other than the basic
Perl interpreter.
To use them as command line utilities, simply chmod +x either
pt2html or html2pt, and pipe data to them:
% ./pt2html example.txt
% ./html2pt test.html
% curl http://oldvcr.blogspot.com/ | ./html2pt | ./pt2html
This document, in fact, was converted with html2pt and
Html2Markdown.
Both tools accept a -debug option, allowing you to see the actual
ProleText tuples and the view of the HTML parser, respectively. Try
./pt2html -debug README.txt to see the tuples generated for this
very document.
To use them as Perl libraries, you can either require "pt2html.pl"
or require "html2pt.pl" (which are symlinks), or
use PeroleText or use PeroleHTML (which are also
symlinks). No modification is needed; the files will do "the right thing"
based on the context you use them in.
The PeroleText converters are line-oriented; you feed lines of text to them until you're out of data. Both have just three methods, differing only in the arguments to the constructor:
my $p = new PeroleText([$debug]);
print $p->proline($string);
print $p->done;
my $p = new PeroleHTML([$debug,][$img]);
print $p->proline($string);
print $p->done;
The $debug argument (0=false, 1=true) indicates whether to run the
converter in debug mode. For ProleText to HTML, this emits the tuples. For HTML
to ProleText, this emits the view of the HTML parser. The second argument, only
for PeroleHTML, says whether to always replace images with their
ALT text (if true, <IMG> tags are used as is).
Any unspecified argument to the constructor is treated as false.
Then, for each line of data, call the method proline (this is a
specific pun I refuse to explain but Canadian Commodore users should get
— hint: Jim Butterfield and Steve Punter), which will return a string
you can print or store. This string may not include all of the elements you
passed it, particularly in the HTML converter, so when you're out of data call
the method done to return anything left over in the object's
buffer. The object instance is not reusable when the conversion is complete;
destroy it or let it go out of scope after calling done, and make
a new instance if you need to do a new operation. Although there are other
"secret" instance methods available for these objects, they should be
considered neither public, stable nor supported.
This is a toy project. I can't imagine you'd use this in a production environment, but if you have any ideas about doing so, slowly back away from the keyboard and think long and hard about the other bad choices you've made in life. Lots of sites probably won't work with the HTML-to-ProleText converter (in fact, those without significant text content will definitely not work). Issues that are not correctable may be closed as out of scope. Pull requests are accepted whenever I get around to them, which may be years from now.