COMP2021 Final Project - LightHTML
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This document discusses using a dispatch table and hash table to route user input to different functions in Perl. It also summarizes using HTML::TreeBuilder to parse HTML into a syntax tree and then manipulate the tree using HTML::Tree and HTML::Element objects. Finally, it recommends two chapters from a book on Perl and LWP that cover HTML processing and modification using parse trees.
![list - ls [options] elements](https://image.slidesharecdn.com/comp2021-130601120541-phpapp02/85/COMP2021-Final-Project-LightHTML-7-320.jpg)
![delete - de [options] elements](https://image.slidesharecdn.com/comp2021-130601120541-phpapp02/85/COMP2021-Final-Project-LightHTML-9-320.jpg)
![delete - de [options] elements](https://image.slidesharecdn.com/comp2021-130601120541-phpapp02/85/COMP2021-Final-Project-LightHTML-10-320.jpg)
![create tree object
HTML::TreeBuilder
#!/usr/bin/perl -w
use warnings FATAL => 'all';
use strict;
use HTML::TreeBuilder;
use Term::ANSIColor;
(@ARGV == 1) || exit print "Usage: [HTML file].n";
(-e $ARGV[0]) || exit print "Input file does not exist.n";
my $root = HTML::TreeBuilder->new;
$root->parse_file($ARGV[0]) || die "$!";
include module](https://image.slidesharecdn.com/comp2021-130601120541-phpapp02/85/COMP2021-Final-Project-LightHTML-17-320.jpg)
COMP2021 Final Project - LightHTML
- 1. Light</HTML>
- 7. list - ls [options] elements
- 8. clean - cl elements
- 9. delete - de [options] elements
- 10. delete - de [options] elements
- 11. DEMO
- 12. Dispatch Table hash of references to executable code
- 13. Dispatch Table my $dispatchTable = { ! a => &func_a, ! b => &func_b, ! q => sub { exit(0) }, }; while ( 1 ) { ! print "Press a key!n"; ! chomp (my $input = <STDIN>); ! if (defined $dispatchTable->($input)) { ! ! $dispatchTable->{$input}->(); ! } } Hash table Get user input reference to function argvs
- 14. Dispatch Table my $myFunc = { ! s => &saveFile, ! de => &deletTag, ! cl => &cleanUp, ! ls => &listTags, ! q => sub { $root = $root->delete; exit(0) }, ! DEFAULT => sub {print ("Command not found.n")} };
- 15. HTML::TreeBuilder Parser that builds a HTML syntax tree http://search.cpan.org/~cjm/HTML-Tree-5.03/lib/HTML/TreeBuilder.pm
- 16. HTML::Tree make parse trees out of HTML source HTML::TreeBuilder builds the parse trees HTML::Element parse trees are made up of element class objects
- 17. create tree object HTML::TreeBuilder #!/usr/bin/perl -w use warnings FATAL => 'all'; use strict; use HTML::TreeBuilder; use Term::ANSIColor; (@ARGV == 1) || exit print "Usage: [HTML file].n"; (-e $ARGV[0]) || exit print "Input file does not exist.n"; my $root = HTML::TreeBuilder->new; $root->parse_file($ARGV[0]) || die "$!"; include module
- 19. Perl & LWP by Sean M. Burke "Fetching web pages, Parsing HTML, Writing Spiders, & More" http://lwp.interglacial.com/index.html Chapter 9 HTML Processing with Trees Chapter 10 Modifying HTML with Trees