JE, version 0.061

JE is a pure-Perl ECMAScript (JavaScript) engine. Here are some of its
advantages:

    - Easy to install (no C compiler necessary)
    - Compatible with Data::Dump::Streamer, so the runtime environment
      can be serialised
    - The parser can be extended/customised to support extra (or
      fewer) language features (not yet complete)
    - All JavaScript datatypes can be manipulated directly from Perl
      (they all have overloaded operators)

Here are its main weakness:
    - It's slow (well, what did you expect?).
    - It uses lots of memory.
    - It leaks memory (to be fixed).

This is still an alpha release, but it fully implements ECMAScript v3,
except for a few seldom-used features like -0.

If  you have the time and the interest,  please experiment  with  this
module (or maybe even lend a hand :-). If you have any ideas as to how
the API could be improved or reworked, please e-mail me.


RECENT CHANGES

Unfortunately,  I made the mistake of making the previous release  ver-
sion 0.54 instead of 0.054. I have reset the version on CPAN, so 0.055
is the current version,  but if anyone has already  upgrade  to  0.054,
future upgrades will not work from  the  CPAN  shell  without  ‘force’.
Hopefully two weeks was short enough an interval.  If this causes prob-
lems for anyone, please let me know and I will increase the version to
.541 or something similar.

0.061
-----
Fixed to work with Perl 5.20.

0.060
-----
Incompatible change: We now require perl 5.8.4 or higher.
Bug fixes:
•  An escaped surrogate in a regular expression now matches that  sur-
   rogate,  instead of trying to match a backslash followed by a lite-
   ral ‘x{d800}’ or similar.
• ‘... ? this : ...’ no longer confuses the run-time  engine,  result-
   ing in an error (RT #79855).
•  The run-time engine now suppresses recursion warnings, which legit-
   imate JavaScript code could trigger.

0.059
-----
New feature:  JE now provides TO_JSON  methods to allow serialisation
with JSON.pm.  Thanks to Toby Inkster for the suggestion  (RT #75369).

0.058
-----
Bug fix: Remove some debugging code inadvertently included in the pre-
vious release.


TO DO

- Make the parser extensible/customisable
- Add more helpful error messages
- Determine some logical way of dealing with locale settings (for
  String.prototype.localeCompare, et al.)
- Finish writing tests
- Deal with circular references
- Finish making built-in JS properties load lazily
- Finish optimising JS compiled code by turning it into Perl code
- Other optimisations


INSTALLATION

The easiest way to install this module is to use the CPAN module or
the cpan script:

    [sudo] perl -MCPAN -e "install JE"

    [sudo] cpan
    cpan> install JE

Or you can use the following:

    perl Makefile.PL
    make
    make test
    [sudo] make install


PREREQUISITES

This module requires perl 5.8.4 or higher and the following modules:
• Scalar::Util version 1.14 or later
• The TimeDate distribution (more precisely, Time::Zone, Date::Format
  and Date::Parse)
• Encode 2.08 or later

For perl versions earlier than 5.9.4 it also requires
Tie::RefHash::Weak.

Later it will probably require Unicode::Collate.

There is a slight incompatibility with perl version 5.8.3. If you try
to create a regular expression with invalid modifiers, you will get a
warning as well as a SyntaxError. This causes one of the test scripts
(parse08-regexps.t) to fail.


DOCUMENTATION

After installing, you can find documentation for this module with the 
perldoc command.

    perldoc JE

Or try using man (it's faster, in my experience):

    man JE


ACKNOWLEDGEMENTS

Thanks to Max Maischein, Kevin Cameron, Chia-liang Kao and Damyan Iva-
nov for their contributions,

to Andy Armstrong, Yair Lenga, Alex Robinson, Christian Forster, Imre
Rad, Craig MacKenna and Toby Inkster for their suggestions,

and to the CPAN Testers for their helpful reports.


COPYRIGHT AND LICENCE

Copyright (C) 2007-14 Father Chrysostomos

This program is free software; you may redistribute it and/or modify
it under the same terms as perl.
