in reply to JavaScript::Parse::PurePerl (was Parse::JavaScript)

I would like it if you would add something like (i really like it when modules are examples of how to use themselves): 
package main;
unless(caller) {
    $\ = "\n\n#######\n\n";
    my $js_parser = Parse::JavaScript->new();
    print $js_parser->parse(<<'_EOJS_');

function foo(bar){    // JS Comment
    window.location = "http://www." + bar + '.com'
}
   var quux = 68;
   var baz = quux++;
_EOJS_

    print $js_parser->parse(q[
        while(1) {
            document.write(" die ");
        }
    ]);

    print $js_parser->parse(q[
        do {
            document.write(" die ");
        } while (1);
    ]);


    print $js_parser->parse(q[
        for(;;) {
            document.write(" die ");
        }
    ]);


    print $js_parser->parse(q[
        document.write( /(\w+)/g.exec("foo bar") );
    ]);

    print $js_parser->parse('
        document.write( /[^\]\[](\w+)/g.exec("foo bar") );
    ');

    print $js_parser->parse(q{
        /* HERE GOES AN ERROR (good job)
    });

 
}

[download]
Good job (++).

Do you know of any valid javascript which might cause an error ? ( the examples above are all valid, and all validate until /* HERE GOES AN ERROR (good job))

____________________________________________________
** The Third rule of perl club is a statement of fact: pod is sexy.

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Re: Re: Parse::JavaScript
by OeufMayo (Curate) on Aug 27, 2002 at 08:45 UTC

    Thanks for your input podmaster. Here are a few valid JavaScript samples that don't parse too well.

    Regexes

    var foo = 3 / 4 + 1 / 2;

    is parsed as :

    var foo = 3;
/ 4 + 1 /;
2;

    [download]

    var foo = (3/4) + 1 / 2; is not parsed at all (though I suspect it could be fixed by adjusting the precedence)

    Elisions (though I have yet to see this construct in a real script)

    var foo = foo[ , , bar];

    Wrong parsing

    bar
++foo;

    [download]

    Is parsed as:

    bar++;
foo;

    [download]

    Which is wrong. the parser should give an error (no line terminator allowed between 'bar' and '++') or be nice and get parse it as bar++;foo;

    The following code is found in one of the the mozilla/js test script, but it doesn't seem to be valid, according to the specs (and obviously, doesn't parse).

    try {
    //some stuff 
}catch (e if e == 3){
    /* do stuff */
}

    [download]

    There are probably some more bugs, but the regex/division confusion is by far the most annoying

    Update here is another major bugs due to the Optional Semicolon:

    return
a + b

    [download]

    Should be:

    return;
a + b;

    [download]

    But it is parsed as

    return a + b;

    This bug is mainly due to the fact that line terminators are silently skipped by the lexer

    Update 2002-09-01: I'm glad to say that all these bugs are now fixed in the current version of this node (except for the elision.)

    -- 
briac
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      Very interesting code and discussion - but my internal parser parses

      bar++
foo;

      [download]
      as 
      bar+ +foo;

      [download]

      which would be instantly valid. But on the other side, I don't know much about JavaScript (and C-style) operator syntax, and maybe two pluses automatically mean postincrement / preincrement operator ...

      perl -MHTTP::Daemon -MHTTP::Response -MLWP::Simple -e ' ;    # The  
$d = new HTTP::Daemon and fork and getprint $d->url and exit;#spider
($c = $d->accept())->get_request(); $c->send_response( new   #in the
HTTP::Response(200,$_,$_,qq(Just another Perl hacker\n))); ' #  web

      [download]
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      I apologise for ressurecting a zombie thread, but just wanted to provide this info just in case anyone else was looking at the parser.

      I had to make the following corrections to get the module to work
      line 1495 comment out the entire line 
      # /*     vi:set syn=yacc: */

      [download]
      to elminate error "Quantifier follows nothing in regex; marked by <-- HERE in m/* <-- HERE  vi:set syn=yacc: */ at PurePerl.yp line 1495."
      And also line 1307 changed from 
      my $temp_pos = pos($$input);
$$input =~ s/\G\s*(\n)\s*([+-]{2})/$1;$2/sg;
pos($$input) = $temp_pos;

      [download]
      to 
      my $temp_pos = pos($$input);
$temp_pos =~ s/\G\s*(\n)\s*([+-]{2})/$1;$2/sg;
pos($$input) = $temp_pos;

      [download]
      to eliminate error "Modification of a read-only value attempted at PurePerl.yp line 1307."
      Hope this is of assistance to someone.
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