Initial public release of WebPerl

7 years ago · 8733c25cd3
commit 8733c25cd3
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--- a/.gitignore
+++ b/.gitignore
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+/*.zip
+/work/
+/emperl5/
+/web/emperl.js
+/web/emperl.wasm
+/web/emperl.data
--- a/LICENSE_artistic.txt
+++ b/LICENSE_artistic.txt
@ -0,0 +1,158 @@
+NAME
+    perlartistic - the Perl Artistic License
+
+SYNOPSIS
+     You can refer to this document in Pod via "L<perlartistic>"
+     Or you can see this document by entering "perldoc perlartistic"
+
+DESCRIPTION
+    Perl is free software; you can redistribute it and/or modify it under
+    the terms of either:
+
+            a) the GNU General Public License as published by the Free
+            Software Foundation; either version 1, or (at your option) any
+            later version, or
+
+            b) the "Artistic License" which comes with this Kit.
+
+    This is "The Artistic License". It's here so that modules, programs,
+    etc., that want to declare this as their distribution license can link
+    to it.
+
+    For the GNU General Public License, see perlgpl.
+
+The "Artistic License"
+  Preamble
+    The intent of this document is to state the conditions under which a
+    Package may be copied, such that the Copyright Holder maintains some
+    semblance of artistic control over the development of the package, while
+    giving the users of the package the right to use and distribute the
+    Package in a more-or-less customary fashion, plus the right to make
+    reasonable modifications.
+
+  Definitions
+    "Package"
+        refers to the collection of files distributed by the Copyright
+        Holder, and derivatives of that collection of files created through
+        textual modification.
+
+    "Standard Version"
+        refers to such a Package if it has not been modified, or has been
+        modified in accordance with the wishes of the Copyright Holder as
+        specified below.
+
+    "Copyright Holder"
+        is whoever is named in the copyright or copyrights for the package.
+
+    "You"
+        is you, if you're thinking about copying or distributing this
+        Package.
+
+    "Reasonable copying fee"
+        is whatever you can justify on the basis of media cost, duplication
+        charges, time of people involved, and so on. (You will not be
+        required to justify it to the Copyright Holder, but only to the
+        computing community at large as a market that must bear the fee.)
+
+    "Freely Available"
+        means that no fee is charged for the item itself, though there may
+        be fees involved in handling the item. It also means that recipients
+        of the item may redistribute it under the same conditions they
+        received it.
+
+  Conditions
+    1.  You may make and give away verbatim copies of the source form of the
+        Standard Version of this Package without restriction, provided that
+        you duplicate all of the original copyright notices and associated
+        disclaimers.
+
+    2.  You may apply bug fixes, portability fixes and other modifications
+        derived from the Public Domain or from the Copyright Holder. A
+        Package modified in such a way shall still be considered the
+        Standard Version.
+
+    3.  You may otherwise modify your copy of this Package in any way,
+        provided that you insert a prominent notice in each changed file
+        stating how and when you changed that file, and provided that you do
+        at least ONE of the following:
+
+        a)  place your modifications in the Public Domain or otherwise make
+            them Freely Available, such as by posting said modifications to
+            Usenet or an equivalent medium, or placing the modifications on
+            a major archive site such as uunet.uu.net, or by allowing the
+            Copyright Holder to include your modifications in the Standard
+            Version of the Package.
+
+        b)  use the modified Package only within your corporation or
+            organization.
+
+        c)  rename any non-standard executables so the names do not conflict
+            with standard executables, which must also be provided, and
+            provide a separate manual page for each non-standard executable
+            that clearly documents how it differs from the Standard Version.
+
+        d)  make other distribution arrangements with the Copyright Holder.
+
+    4.  You may distribute the programs of this Package in object code or
+        executable form, provided that you do at least ONE of the following:
+
+        a)  distribute a Standard Version of the executables and library
+            files, together with instructions (in the manual page or
+            equivalent) on where to get the Standard Version.
+
+        b)  accompany the distribution with the machine-readable source of
+            the Package with your modifications.
+
+        c)  give non-standard executables non-standard names, and clearly
+            document the differences in manual pages (or equivalent),
+            together with instructions on where to get the Standard Version.
+
+        d)  make other distribution arrangements with the Copyright Holder.
+
+    5.  You may charge a reasonable copying fee for any distribution of this
+        Package. You may charge any fee you choose for support of this
+        Package. You may not charge a fee for this Package itself. However,
+        you may distribute this Package in aggregate with other (possibly
+        commercial) programs as part of a larger (possibly commercial)
+        software distribution provided that you do not advertise this
+        Package as a product of your own. You may embed this Package's
+        interpreter within an executable of yours (by linking); this shall
+        be construed as a mere form of aggregation, provided that the
+        complete Standard Version of the interpreter is so embedded.
+
+    6.  The scripts and library files supplied as input to or produced as
+        output from the programs of this Package do not automatically fall
+        under the copyright of this Package, but belong to whoever generated
+        them, and may be sold commercially, and may be aggregated with this
+        Package. If such scripts or library files are aggregated with this
+        Package via the so-called "undump" or "unexec" methods of producing
+        a binary executable image, then distribution of such an image shall
+        neither be construed as a distribution of this Package nor shall it
+        fall under the restrictions of Paragraphs 3 and 4, provided that you
+        do not represent such an executable image as a Standard Version of
+        this Package.
+
+    7.  C subroutines (or comparably compiled subroutines in other
+        languages) supplied by you and linked into this Package in order to
+        emulate subroutines and variables of the language defined by this
+        Package shall not be considered part of this Package, but are the
+        equivalent of input as in Paragraph 6, provided these subroutines do
+        not change the language in any way that would cause it to fail the
+        regression tests for the language.
+
+    8.  Aggregation of this Package with a commercial distribution is always
+        permitted provided that the use of this Package is embedded; that
+        is, when no overt attempt is made to make this Package's interfaces
+        visible to the end user of the commercial distribution. Such use
+        shall not be construed as a distribution of this Package.
+
+    9.  The name of the Copyright Holder may not be used to endorse or
+        promote products derived from this software without specific prior
+        written permission.
+
+    10. THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED
+        WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
+        MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+
+    The End
+
--- a/LICENSE_gpl.txt
+++ b/LICENSE_gpl.txt
@ -0,0 +1,281 @@
+NAME
+    perlgpl - the GNU General Public License, version 1
+
+SYNOPSIS
+     You can refer to this document in Pod via "L<perlgpl>"
+     Or you can see this document by entering "perldoc perlgpl"
+
+DESCRIPTION
+    Perl is free software; you can redistribute it and/or modify it under
+    the terms of either:
+
+            a) the GNU General Public License as published by the Free
+            Software Foundation; either version 1, or (at your option) any
+            later version, or
+
+            b) the "Artistic License" which comes with this Kit.
+
+    This is the "GNU General Public License, version 1". It's here so that
+    modules, programs, etc., that want to declare this as their distribution
+    license can link to it.
+
+    For the Perl Artistic License, see perlartistic.
+
+GNU GENERAL PUBLIC LICENSE
+                        GNU GENERAL PUBLIC LICENSE
+                         Version 1, February 1989
+
+      Copyright (C) 1989 Free Software Foundation, Inc.
+                    51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+
+      Everyone is permitted to copy and distribute verbatim copies
+      of this license document, but changing it is not allowed.
+
+                                Preamble
+
+       The license agreements of most software companies try to keep users
+     at the mercy of those companies.  By contrast, our General Public
+     License is intended to guarantee your freedom to share and change free
+     software--to make sure the software is free for all its users.  The
+     General Public License applies to the Free Software Foundation's
+     software and to any other program whose authors commit to using it.
+     You can use it for your programs, too.
+
+       When we speak of free software, we are referring to freedom, not
+     price.  Specifically, the General Public License is designed to make
+     sure that you have the freedom to give away or sell copies of free
+     software, that you receive source code or can get it if you want it,
+     that you can change the software or use pieces of it in new free
+     programs; and that you know you can do these things.
+
+       To protect your rights, we need to make restrictions that forbid
+     anyone to deny you these rights or to ask you to surrender the rights.
+     These restrictions translate to certain responsibilities for you if you
+     distribute copies of the software, or if you modify it.
+
+       For example, if you distribute copies of a such a program, whether
+     gratis or for a fee, you must give the recipients all the rights that
+     you have.  You must make sure that they, too, receive or can get the
+     source code.  And you must tell them their rights.
+
+       We protect your rights with two steps: (1) copyright the software,
+     and (2) offer you this license which gives you legal permission to
+     copy, distribute and/or modify the software.
+
+       Also, for each author's protection and ours, we want to make certain
+     that everyone understands that there is no warranty for this free
+     software.  If the software is modified by someone else and passed on,
+     we want its recipients to know that what they have is not the original,
+     so that any problems introduced by others will not reflect on the
+     original authors' reputations.
+
+       The precise terms and conditions for copying, distribution and
+     modification follow.
+
+                        GNU GENERAL PUBLIC LICENSE
+        TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
+
+       0. This License Agreement applies to any program or other work which
+     contains a notice placed by the copyright holder saying it may be
+     distributed under the terms of this General Public License.  The
+     "Program", below, refers to any such program or work, and a "work based
+     on the Program" means either the Program or any work containing the
+     Program or a portion of it, either verbatim or with modifications.
+     Each licensee is addressed as "you".
+
+       1. You may copy and distribute verbatim copies of the Program's
+     source code as you receive it, in any medium, provided that you
+     conspicuously and appropriately publish on each copy an appropriate
+     copyright notice and disclaimer of warranty; keep intact all the
+     notices that refer to this General Public License and to the absence of
+     any warranty; and give any other recipients of the Program a copy of
+     this General Public License along with the Program.  You may charge a
+     fee for the physical act of transferring a copy.
+
+       2. You may modify your copy or copies of the Program or any portion
+     of it, and copy and distribute such modifications under the terms of
+     Paragraph 1 above, provided that you also do the following:
+
+         a) cause the modified files to carry prominent notices stating that
+         you changed the files and the date of any change; and
+
+         b) cause the whole of any work that you distribute or publish, that
+         in whole or in part contains the Program or any part thereof,
+         either with or without modifications, to be licensed at no charge
+         to all third parties under the terms of this General Public License
+         (except that you may choose to grant warranty protection to some or
+         all third parties, at your option).
+
+         c) If the modified program normally reads commands interactively
+         when run, you must cause it, when started running for such
+         interactive use in the simplest and most usual way, to print or
+         display an announcement including an appropriate copyright notice
+         and a notice that there is no warranty (or else, saying that you
+         provide a warranty) and that users may redistribute the program
+         under these conditions, and telling the user how to view a copy of
+         this General Public License.
+
+         d) You may charge a fee for the physical act of transferring a
+         copy, and you may at your option offer warranty protection in
+         exchange for a fee.
+
+     Mere aggregation of another independent work with the Program (or its
+     derivative) on a volume of a storage or distribution medium does not
+     bring the other work under the scope of these terms.
+
+       3. You may copy and distribute the Program (or a portion or
+     derivative of it, under Paragraph 2) in object code or executable form
+     under the terms of Paragraphs 1 and 2 above provided that you also do
+     one of the following:
+
+         a) accompany it with the complete corresponding machine-readable
+         source code, which must be distributed under the terms of
+         Paragraphs 1 and 2 above; or,
+
+         b) accompany it with a written offer, valid for at least three
+         years, to give any third party free (except for a nominal charge
+         for the cost of distribution) a complete machine-readable copy of
+         the corresponding source code, to be distributed under the terms of
+         Paragraphs 1 and 2 above; or,
+
+         c) accompany it with the information you received as to where the
+         corresponding source code may be obtained.  (This alternative is
+         allowed only for noncommercial distribution and only if you
+         received the program in object code or executable form alone.)
+
+     Source code for a work means the preferred form of the work for making
+     modifications to it.  For an executable file, complete source code
+     means all the source code for all modules it contains; but, as a
+     special exception, it need not include source code for modules which
+     are standard libraries that accompany the operating system on which the
+     executable file runs, or for standard header files or definitions files
+     that accompany that operating system.
+
+       4. You may not copy, modify, sublicense, distribute or transfer the
+     Program except as expressly provided under this General Public License.
+     Any attempt otherwise to copy, modify, sublicense, distribute or
+     transfer the Program is void, and will automatically terminate your
+     rights to use the Program under this License.  However, parties who
+     have received copies, or rights to use copies, from you under this
+     General Public License will not have their licenses terminated so long
+     as such parties remain in full compliance.
+
+       5. By copying, distributing or modifying the Program (or any work
+     based on the Program) you indicate your acceptance of this license to
+     do so, and all its terms and conditions.
+
+       6. Each time you redistribute the Program (or any work based on the
+     Program), the recipient automatically receives a license from the
+     original licensor to copy, distribute or modify the Program subject to
+     these terms and conditions.  You may not impose any further
+     restrictions on the recipients' exercise of the rights granted herein.
+
+       7. The Free Software Foundation may publish revised and/or new
+     versions of the General Public License from time to time.  Such new
+     versions will be similar in spirit to the present version, but may
+     differ in detail to address new problems or concerns.
+
+     Each version is given a distinguishing version number.  If the Program
+     specifies a version number of the license which applies to it and "any
+     later version", you have the option of following the terms and
+     conditions either of that version or of any later version published by
+     the Free Software Foundation.  If the Program does not specify a
+     version number of the license, you may choose any version ever
+     published by the Free Software Foundation.
+
+       8. If you wish to incorporate parts of the Program into other free
+     programs whose distribution conditions are different, write to the
+     author to ask for permission.  For software which is copyrighted by the
+     Free Software Foundation, write to the Free Software Foundation; we
+     sometimes make exceptions for this.  Our decision will be guided by the
+     two goals of preserving the free status of all derivatives of our free
+     software and of promoting the sharing and reuse of software generally.
+
+                                NO WARRANTY
+
+       9. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO
+     WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW.
+     EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR
+     OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND,
+     EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+     WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+     THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS
+     WITH YOU.  SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
+     ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
+
+       10. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN
+     WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY
+     AND/OR REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU
+     FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR
+     CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE
+     PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING
+     RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A
+     FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), EVEN IF
+     SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
+     DAMAGES.
+
+                         END OF TERMS AND CONDITIONS
+
+            Appendix: How to Apply These Terms to Your New Programs
+
+       If you develop a new program, and you want it to be of the greatest
+     possible use to humanity, the best way to achieve this is to make it
+     free software which everyone can redistribute and change under these
+     terms.
+
+       To do so, attach the following notices to the program.  It is safest
+     to attach them to the start of each source file to most effectively
+     convey the exclusion of warranty; and each file should have at least
+     the "copyright" line and a pointer to where the full notice is found.
+
+         <one line to give the program's name and a brief idea of what it
+         does.>
+         Copyright (C) 19yy  <name of author>
+
+         This program is free software; you can redistribute it and/or
+         modify it under the terms of the GNU General Public License as
+         published by the Free Software Foundation; either version 1, or (at
+         your option) any later version.
+
+         This program is distributed in the hope that it will be useful,
+         but WITHOUT ANY WARRANTY; without even the implied warranty of
+         MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+         GNU General Public License for more details.
+
+         You should have received a copy of the GNU General Public License
+         along with this program; if not, write to the Free Software
+         Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA
+         02110-1301 USA
+
+
+     Also add information on how to contact you by electronic and paper
+     mail.
+
+     If the program is interactive, make it output a short notice like this
+     when it starts in an interactive mode:
+
+         Gnomovision version 69, Copyright (C) 19xx name of author
+         Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type
+         'show w'.  This is free software, and you are welcome to
+         redistribute it under certain conditions; type 'show c' for
+         details.
+
+     The hypothetical commands 'show w' and 'show c' should show the
+     appropriate parts of the General Public License.  Of course, the
+     commands you use may be called something other than 'show w' and 'show
+     c'; they could even be mouse-clicks or menu items--whatever suits your
+     program.
+
+     You should also get your employer (if you work as a programmer) or your
+     school, if any, to sign a "copyright disclaimer" for the program, if
+     necessary.  Here a sample; alter the names:
+
+       Yoyodyne, Inc., hereby disclaims all copyright interest in the
+       program 'Gnomovision' (a program to direct compilers to make passes
+       at assemblers) written by James Hacker.
+
+       <signature of Ty Coon>, 1 April 1989
+       Ty Coon, President of Vice
+
+     That's all there is to it!
+
--- a/README.md
+++ b/README.md
@ -0,0 +1,39 @@
+
+WebPerl
+=======
+
+This is the main WebPerl repository.
+Please see the documentation on the main site **<http://webperl.zero-g.net>**:
+
+\[ [Home](https://webperl.zero-g.net/index.html) -
+[Using WebPerl](https://webperl.zero-g.net/using.html) -
+[Building WebPerl](https://webperl.zero-g.net/building.html) -
+[Wiki](https://github.com/haukex/webperl/wiki) -
+[GitHub](https://github.com/haukex/webperl) -
+[Notes](https://webperl.zero-g.net/notes.html) -
+[Legal](https://webperl.zero-g.net/legal.html) \]
+
+
+Author, Copyright, and License
+==============================
+
+**WebPerl <http://webperl.zero-g.net>**
+
+Copyright (c) 2018 Hauke Daempfling (haukex@zero-g.net)
+at the Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB),
+Berlin, Germany, <http://www.igb-berlin.de>
+
+This program is free software; you can redistribute it and/or modify
+it under the same terms as Perl 5 itself: either the GNU General Public
+License as published by the Free Software Foundation (either version 1,
+or, at your option, any later version), or the "Artistic License" which
+comes with Perl 5.
+
+This program is distributed in the hope that it will be useful, but
+**WITHOUT ANY WARRANTY**; without even the implied warranty of
+**MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE**.
+See the licenses for details.
+
+You should have received a copy of the licenses along with this program.
+If not, see <http://perldoc.perl.org/index-licence.html>.
+
--- a/ToDo.md
+++ b/ToDo.md
@ -0,0 +1,31 @@
+
+WebPerl TODOs
+=============
+
+<http://webperl.zero-g.net>
+
+1. Documentation (Website)
+	
+	- Using WebPerl
+		- the user must explicitly "unregister" anonymous Perl subs (or show alternatives) to prevent %CodeTable from growing too large
+		- the user shouldn't mess with the symbol table (delete subs, redefine them, etc.)
+		- <http://kripken.github.io/emscripten-site/docs/compiling/Deploying-Pages.html>
+	- Building WebPerl
+		- test out perl -Mlazy to install all the deps (and if it works well, document)
+
+2. Testing
+	
+	- Continue work on `WebPerl.t`
+		- More tests for Unicode support (Perl/JS interface, Perl.eval(), plus Emscripten's virtual FS)
+	- I should focus on getting the tests running in the browser instead of node.js
+		- How to package tests? How does `make test` find&handle all the various modules' `t`s?
+	- How to best disable individual tests that we know won't work? (qx etc.)
+	- How to handle the many tests that call an external Perl?
+		- patching t/test.pl's runperl() seems easiest at the moment, and we can use the iframe method from the IDE
+
+3. Misc
+
+	- Test if a CDN would work
+
+See also: "TODO" tags in code (use `findtodo.sh`)
+
--- a/build/build.pl
+++ b/build/build.pl
@ -0,0 +1,465 @@
+#!/usr/bin/env perl
+use warnings;
+use 5.026;
+
+=head1 SYNOPSIS
+
+Build script for WebPerl; see L<http://webperl.zero-g.net>.
+
+ build.pl [OPTIONS]
+ OPTIONS:
+   --showconf     - Show configuration
+   --reconfig     - Force regeneration config.sh
+   --forceext     - Force fetching of extensions
+   --applyconfig  - Apply any changes to config.sh (sh Configure -S)
+   --remakeout    - Force rebuild of the output directory
+   --forceemperl  - Force rebuild of emperl.js
+   --dist=FN      - Create a distro file "FN.zip"
+   --verbose      - Be more verbose
+
+=head1 Author, Copyright, and License
+
+B<< WebPerl L<http://webperl.zero-g.net> >>
+
+Copyright (c) 2018 Hauke Daempfling (haukex@zero-g.net)
+at the Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB),
+Berlin, Germany, L<http://www.igb-berlin.de>
+
+This program is free software; you can redistribute it and/or modify
+it under the same terms as Perl 5 itself: either the GNU General Public
+License as published by the Free Software Foundation (either version 1,
+or, at your option, any later version), or the "Artistic License" which
+comes with Perl 5.
+
+This program is distributed in the hope that it will be useful, but
+B<WITHOUT ANY WARRANTY>; without even the implied warranty of
+B<MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE>.
+See the licenses for details.
+
+You should have received a copy of the licenses along with this program.
+If not, see L<http://perldoc.perl.org/index-licence.html>.
+
+=cut
+
+use Getopt::Long qw/ HelpMessage :config posix_default gnu_compat bundling auto_version auto_help /;
+use Hash::Util qw/lock_hash/;
+use Data::Dump;
+use Path::Class qw/file dir/;
+use IPC::Run3::Shell {show_cmd=>1}, qw/ :FATAL :run git make emmake /;
+use ExtUtils::MakeMaker qw/prompt/;
+use FindBin ();
+use Carp;
+use Cwd qw/getcwd abs_path/;
+use URI ();
+use IO::Socket::SSL 1.56 (); # for HTTP::Tiny
+use Net::SSLeay 1.49 ();     # for HTTP::Tiny
+use HTTP::Tiny ();
+use Cpanel::JSON::XS qw/decode_json/;
+use File::Temp qw/tempdir/;
+use Archive::Tar ();
+use File::Copy::Recursive qw/dirmove/;
+use File::Replace qw/replace3/;
+use Pod::Strip ();
+use Archive::Zip qw/AZ_OK/;
+
+GetOptions(\my %opts,'showconf','reconfig','forceext','applyconfig',
+	'forceemperl','remakeout','dist=s','verbose')
+	or HelpMessage(-exitval=>255);
+
+# check that emperl_config.sh has been run
+die "Please run '. emperl_config.sh' to set up the environment variables.\n"
+	unless $ENV{EMPERL_PERLVER};
+die "Please edit 'emperl_config.sh' to point it to the correct location of 'emsdk_env.sh'\n"
+	unless $ENV{EMSCRIPTEN} && -d $ENV{EMSCRIPTEN} && $ENV{EMSDK} && -d $ENV{EMSDK};
+
+# copy over config variables from environment
+my %C = map {$_=>$ENV{'EMPERL_'.$_}} qw/ EXTENSIONS
+	HOSTPERLDIR OUTPUTDIR DOWNLOADDIR PERLSRCDIR
+	PREFIX PERLVER
+	PERL_REPO PERL_BRANCH CLOBBER_BRANCH /;
+$C{$_} = dir($C{$_}) for qw/ HOSTPERLDIR OUTPUTDIR DOWNLOADDIR PERLSRCDIR /;
+$C{EXTENSIONS} = [ split ' ', $C{EXTENSIONS} ];
+lock_hash %C;  # typo prevention
+dd \%C if $opts{showconf};
+
+my $VERBOSE = $opts{verbose}?1:0;
+my $needs_reconfig = !!$opts{reconfig};
+
+# ##### ##### ##### Step: Patch Emscripten ##### ##### #####
+
+{
+	my $d = pushd( dir($ENV{EMSCRIPTEN}, 'src') );
+	# Emscripten's fork() (and system()) stubs return EAGAIN, meaning "Resource temporarily unavailable".
+	# So perl will wait 5 seconds and try again, which is not helpful to us, since Emscripten doesn't support those functions at all.
+	# This patch fixes that on the Emscripten side, so the stubs return ENOTSUP.
+	#TODO Later: we should probably verify the Emscripten version too, and in the future we may need different patches for different versions
+	if ( try_patch_file( file($FindBin::Bin,'emscripten_1.38.10_eagain.patch') ) ) {
+		say STDERR "# Emscripten was newly patched, forcing a rebuild";
+		# not sure if the following is needed, but playing it safe:
+		run 'emcc', '--clear-cache';  # force Emscripten to rebuild libs (takes a bit of time)
+		$needs_reconfig=1;
+	}
+}
+
+# ##### ##### ##### Step: Check out Perl sources ##### ##### #####
+
+if (!-e $C{PERLSRCDIR}) {
+	say STDERR "# $C{PERLSRCDIR} doesn't exist, checking out";
+	my $d = pushd($C{PERLSRCDIR}->parent);
+	git 'clone', '--branch', $C{PERL_BRANCH}, $C{PERL_REPO}, $C{PERLSRCDIR}->basename;
+	die "something went wrong with git clone" unless -d $C{PERLSRCDIR};
+	$needs_reconfig=1;
+}
+{
+	my $d = pushd($C{PERLSRCDIR});
+	git 'fetch';
+	my $myhead = git 'log', '-1', '--format=%h', $C{PERL_BRANCH}, {chomp=>1,show_cmd=>$VERBOSE};
+	my $remhead = git 'log', '-1', '--format=%h', 'origin/'.$C{PERL_BRANCH}, {chomp=>1,show_cmd=>$VERBOSE};
+	say STDERR "# Local branch is at $myhead, remote is $remhead";
+	if ($myhead ne $remhead) {
+		if (prompt("Would you like to update? WARNING: Unsaved local changes may be lost! [Yn]","y")=~/^\s*y/i) {
+			eval {
+				if ($C{CLOBBER_BRANCH}) {
+					say "WARNING: I am about to clobber the branch $C{PERL_BRANCH} in $C{PERLSRCDIR}!";
+					verify_perlsrc_modify(1);
+					git 'checkout', '-q', $C{PERLVER};
+					git 'branch', '-D', $C{PERL_BRANCH};
+					git 'branch', $C{PERL_BRANCH}, 'origin/'.$C{PERL_BRANCH};
+					git 'checkout', $C{PERL_BRANCH};
+				}
+				else {
+					git 'checkout', $C{PERL_BRANCH};
+					git 'pull';
+				}
+			1 } or die "$@\nA git step failed - perhaps you have uncommited changes in $C{PERLSRCDIR}?\n";
+			$needs_reconfig=1;
+		}
+	}
+	my $tags = git 'tag', '--list', {show_cmd=>$VERBOSE};
+	die "could not find tag '$C{PERLVER}', is this the right repository?"
+		unless $tags=~/^\Q$C{PERLVER}\E$/m;
+	my $branches = git 'branch', '--list', {show_cmd=>$VERBOSE};
+	die "could not find branch '$C{PERL_BRANCH}', is this the right repository?"
+		unless $branches=~/^\*?\s*\b\Q$C{PERL_BRANCH}\E$/m;
+	say STDERR "# Found tag '$C{PERLVER}' and branch '$C{PERL_BRANCH}' in $C{PERLSRCDIR}";
+}
+sub verify_perlsrc_modify {
+	my $force = shift;
+	state $already_prompted = 0;
+	$already_prompted=0 if $force;
+	return if $already_prompted;
+	if (prompt("WARNING: You will lose any changes to the working copy and index in $C{PERLSRCDIR}!\n"
+		."    Continue? [yN]","n")!~/^\s*y/i) {
+		say STDERR "Aborting.";
+		exit 1;
+	} else { $already_prompted = 1 }
+}
+
+# ##### ##### ##### Step: Check/build hostperl ##### ##### #####
+
+sub verify_hostperl {
+	my $miniperl = $C{HOSTPERLDIR}->file('miniperl');
+	return 0 unless -e $miniperl;
+	my $miniperlver = run $miniperl, '-e', 'print $^V', {show_cmd=>$VERBOSE};
+	say STDERR "# Detected hostperl / miniperl '$miniperlver' (need '$C{PERLVER}')";
+	my $perl = $C{HOSTPERLDIR}->file('perl');
+	if (-e $perl) { # currently just an optional check
+		my $perlver = run $perl, '-e', 'print $^V', {show_cmd=>$VERBOSE};
+		say STDERR "# Detected hostperl / perl '$perlver'";
+		die "miniperl ('$miniperlver') / perl ('$perlver') version mismatch"
+			unless $miniperlver eq $perlver;
+	}
+	return $miniperlver eq $C{PERLVER};
+}
+if (!verify_hostperl()) {
+	say STDERR "# A rebuild of hostperl is required";
+	$C{HOSTPERLDIR}->rmtree(1);
+	$C{HOSTPERLDIR}->mkpath(1);
+	verify_perlsrc_modify();
+	{
+		my $d = pushd($C{PERLSRCDIR});
+		git 'checkout', '-qf', $C{PERLVER};
+		git 'clean', '-dxf';
+	}
+	{
+		my $d = pushd($C{HOSTPERLDIR});
+		run {stdin=>\undef}, 'sh', file($C{PERLSRCDIR},'Configure'),
+			'-des', '-Dusedevel', '-Dmksymlinks';
+		make 'miniperl';
+		make 'minitest';
+		make 'generate_uudmap';
+		#TODO Later: do we really need the following full perl build as well? (good for testing?)
+		# if we do, make the test for "perl" in verify_hostperl required, not optional
+		make 'perl';
+		make 'test';
+	}
+	$needs_reconfig=1;
+	die "something went wrong with hostperl" unless verify_hostperl();
+}
+
+# ##### ##### ##### Step: Prep "emperl" sources (for next steps) ##### ##### #####
+
+my $config_sh = $C{PERLSRCDIR}->file('config.sh');
+if (!-e $config_sh) {
+	say STDERR "# config.sh NOT found, forcing a reconfig";
+	$needs_reconfig=1 }
+else { say STDERR "# config.sh found" }
+
+if (-e $config_sh) {
+	my $our_mtime = file($FindBin::Bin, 'emperl_config.sh')->stat->mtime;
+	my $perl_mtime = $config_sh->stat->mtime;
+	if ($perl_mtime>$our_mtime)
+		{ say STDERR "# config.sh is newer than emperl_config.sh" }
+	else {
+		say STDERR "# config.sh is OLDER than emperl_config.sh, forcing a reconfig";
+		$needs_reconfig=1 }
+}
+
+if ($needs_reconfig) {
+	exit 1 if prompt("Looks like we need a full reconfig. Continue? [Yn]","y")!~/^\s*y/i;
+	verify_perlsrc_modify();
+	my $d = pushd($C{PERLSRCDIR});
+	# Note: could get the current branch with: git 'rev-parse', '--abbrev-ref', 'HEAD', {chomp=>1};
+	# but since we're clobbering anyway...
+	git 'checkout', '-qf', $C{PERL_BRANCH};
+	git 'clean', '-dxf';
+}
+
+# ##### ##### ##### Step: Add custom extensions ##### ##### #####
+
+if ($needs_reconfig || $opts{forceext}) {
+	my $http = HTTP::Tiny->new;
+	$C{DOWNLOADDIR}->mkpath(1);
+	for my $modname ($C{EXTENSIONS}->@*) {
+		my $apiuri = URI->new('https://fastapi.metacpan.org/v1/download_url');
+		$apiuri->path_segments( $apiuri->path_segments, $modname );
+		say STDERR "# Fetching $apiuri...";
+		my $resp1 = $http->get($apiuri);
+		die "$apiuri: $resp1->{status} $resp1->{reason}\n" unless $resp1->{success};
+		my $apiresp = decode_json($resp1->{content});
+		my $version = $apiresp->{version};
+		my $dluri = URI->new($apiresp->{download_url});
+		
+		my $file = $C{DOWNLOADDIR}->file( ($dluri->path_segments)[-1] );
+		die "I don't know what to do with this file type (yet): $file"
+			unless $file->basename=~/(?:\.tar\.gz|\.tgz)$/i;
+		
+		say STDERR "# Fetching $dluri into $file...";
+		my $resp2 = $http->mirror($dluri, $file);
+		die "$dluri: $resp2->{status} $resp2->{reason}\n" unless $resp2->{success};
+		say STDERR "# $dluri: $resp2->{status} $resp2->{reason}";
+		
+		my $tempd = dir( tempdir(DIR=>$C{DOWNLOADDIR}, CLEANUP => 1) );
+		{
+			my $d = pushd($tempd);
+			my @files = Archive::Tar->new->extract_archive($file, Archive::Tar::COMPRESS_GZIP);
+			say STDERR "# Extracted ",0+@files," files into $tempd";
+		}
+		
+		my @dirs = $tempd->children;
+		die "Can't handle the directory structure of this file (yet): $file"
+			unless @dirs==1 && $dirs[0]->is_dir;
+		my ($dirname) = $dirs[0]->basename =~ /^(.+)-\Q$version\E$/g
+			or die "Failed to parse ".$dirs[0]->basename;
+		my $targdir = $C{PERLSRCDIR}->subdir( 'ext', $dirname );
+		my $domove = 1;
+		if (-e $targdir) {
+			if ( prompt("WARNING: $targdir exists, Keep or Delete? [Kd]","k")=~/^\s*d/i )
+				{ $targdir->rmtree(1) }
+			else { $domove=0 }
+		}
+		if ($domove) {
+			say STDERR "# Moving $dirs[0] to $targdir";
+			dirmove($dirs[0], $targdir)
+				or die "move failed: $!";
+		}
+	}
+	say STDERR "# Done setting up modules";
+}
+else { say STDERR "# Since we don't need a reconfig, not looking at extensions" }
+
+# ##### ##### ##### Step: Run configure ##### ##### #####
+
+if ($needs_reconfig) { # this means that we cleaned the source tree above
+	say STDERR "# Running Configure...";
+	my $d = pushd($C{PERLSRCDIR});
+	# note that we don't use -Dmksymlinks here because something in the
+	# Emscripten build process seems to have issues with the symlinks (?)
+	run {stdin=>\undef}, 'emconfigure', 'sh', 'Configure', '-des',
+		'-Dhintfile=emscripten';
+}
+elsif ($opts{applyconfig}) {
+	say STDERR "# Running Configure -S...";
+	my $d = pushd($C{PERLSRCDIR});
+	run {stdin=>\undef}, 'emconfigure', 'sh', 'Configure', '-S';
+}
+
+# ##### ##### ##### Step: Build perl into outputdir ##### ##### #####
+
+my $destdir = dir($C{OUTPUTDIR},$C{PREFIX});
+if ($needs_reconfig || !-e $destdir || $opts{remakeout}) {
+	say STDERR "# Rebuilding $destdir...";
+	$destdir->rmtree(1);
+	# make the target dir here so that nodeperl_dev_prerun.js can mount it during build
+	$destdir->mkpath(1);
+	
+	my $d = pushd($C{PERLSRCDIR});
+	
+	emmake 'make', 'perl';
+	
+	# a really basic test to see if the build succeeded
+	my $perltest = run file($C{PERLSRCDIR},'perl'), '-e', q{print "$^O $^V"},
+		{chomp=>1,show_cmd=>$VERBOSE,fail_on_stderr=>1};
+	die "something went wrong building perl (got: '$perltest')"
+		unless $perltest eq 'emscripten '.$C{PERLVER};
+	
+	# note that installperl requires ./perl to be executable (our Makefile patch currently takes care of that)
+	run $C{HOSTPERLDIR}.'/miniperl', 'installperl', '-p', '--destdir='.$C{OUTPUTDIR};
+	
+	# clean out the stuff we really don't need
+	$destdir->subdir('bin')->rmtree(1);
+	$destdir->recurse( callback => sub {
+		my $f = shift;
+		return if $f->is_dir;
+		if ( ( $f->basename=~/\.(?:h|a|pod)$/i ) || ( $f->basename eq 'extralibs.ld' && (-s $f)==1 )
+		  || ( $f->basename eq '.packlist' ) ) {
+			print STDERR "removing $f\n";
+			$f->remove or die "failed to remove $f";
+		}
+		elsif ( $f->basename=~/\.(?:pm|pl)$/i && $f->basename ne 'WebPerl.pm' ) {
+			print STDERR "stripping POD from $f\n";
+			my $strip = Pod::Strip->new;
+			my ($infh,$outfh,$repl) = replace3($f);
+			$strip->output_fh($outfh);
+			$strip->parse_file($infh);
+			$repl->finish;
+		}
+	});
+	CLEAN_EMPTY: {
+		my @todel;
+		$destdir->recurse( callback => sub { push @todel, $_[0] if $_[0]->is_dir && !$_[0]->children } );
+		for my $f (@todel) {
+			print STDERR "removing $f\n";
+			$f->remove or die "failed to remove $f";
+		}
+		redo CLEAN_EMPTY if @todel;
+	}
+	
+	# Development aides:
+	$destdir->subdir('dev')->mkpath(1);
+	# we make them hard links so that edits to WebPerl.pm don't require a full
+	# rebuild of the output directory (a rebuild of emperl.js is enough)
+	safelink( $C{PERLSRCDIR}->file('ext','WebPerl','WebPerl.t'),
+		$destdir->file('dev','WebPerl.t') );
+	safelink( $C{PERLSRCDIR}->file('ext','WebPerl','WebPerl.pm'),
+		$destdir->file('lib','5.28.0','wasm','WebPerl.pm') ); #TODO: should figure this directory out dynamically
+	
+	say STDERR "# Done rebuilding $destdir";
+}
+
+# ##### ##### ##### Step: Build emperl.js ##### ##### #####
+
+{
+	say STDERR "# Making emperl.js...";
+	if ($opts{forceemperl})
+		{ $C{PERLSRCDIR}->file('emperl.js')->remove
+			or die "failed to delete emperl.js" }
+	my $d = pushd($C{PERLSRCDIR});
+	emmake 'make', 'emperl.js';
+	say STDERR "# Done making emperl.js";
+}
+for my $f (qw/ emperl.js emperl.wasm emperl.data /) {
+	$C{PERLSRCDIR}->file($f)
+		->copy_to( dir($FindBin::Bin)->parent->subdir('web') )
+			or die "failed to copy $f: $!";
+}
+say STDERR "# Copied emperl.* files to web dir";
+
+# ##### ##### ##### Step: Build distro ##### ##### #####
+
+if (my $dist = $opts{dist}) {
+	my $basedir = dir($FindBin::Bin)->parent;
+	my $zipfn = $basedir->file("$dist.zip");
+	my $zip = Archive::Zip->new();
+	$zip->addTree($basedir->subdir('web').'', dir($dist).'');
+	$zip->writeToFileNamed("$zipfn") == AZ_OK or die "$zipfn write error";
+	say STDERR "# Wrote to $zipfn:";
+	my $unzip = Archive::Zip->new("$zipfn");
+	say "\t$_" for $unzip->memberNames;
+}
+
+
+# ##### ##### ##### subs ##### ##### #####
+
+sub safelink {  # like link(OLDFILE,NEWFILE) but with extra checks
+	my ($oldfile,$newfile) = @_;
+	die "not a file: $oldfile" unless -f $oldfile;
+	if (-e $newfile) {
+		die "files don't match: $oldfile vs. $newfile"
+			unless do { open my $fh, '<:raw', $oldfile or die "$oldfile: $!"; local $/; <$fh> }
+			    eq do { open my $fh, '<:raw', $newfile or die "$newfile: $!"; local $/; <$fh> };
+		file($newfile)->remove or die "failed to remove $newfile: $!";
+	}
+	link($oldfile,$newfile)
+		or die "link('$oldfile','$newfile'): $!";
+}
+
+# First argument: the filename of the .patch file
+# Any following arguments are additionally passed to "patch" (e.g. "-p1")
+# Attempts to run "patch", will fail gracefully if the patch has already been applied.
+# Dies if anything goes wrong (patch not applied cleanly, etc.).
+# Returns false (0) if the patch was already applied previously, true (1) if the patch was newly applied.
+sub try_patch_file {
+	my ($patchf,@args) = @_;
+	say STDERR "# Attempting to apply patch $patchf...";
+	run 'patch', @args, '-r-', '-sNi', $patchf, {allow_exit=>[0,1],show_cmd=>$VERBOSE};
+	if ($?==1<<8) {
+		# Slightly hackish way to test if the patch did not apply cleanly, or it's just already been applied:
+		# Apply the patch in reverse once, and then apply it again, if both go through without errors all is ok.
+		# There is probably a better way to do this, I'm just feeling a little lazy at the moment.
+		run 'patch', @args, '-sRi', $patchf, {show_cmd=>$VERBOSE};
+		run 'patch', @args, '-si',  $patchf, {show_cmd=>$VERBOSE};
+		say STDERR "# Verified that $patchf was previously applied";
+		return 0;
+	}
+	elsif ($?) { die "patch $patchf \$?=$?" }
+	else { say STDERR "# Successfully applied patch $patchf"; return 1 }
+}
+
+# A simplified version of File::pushd that outputs debug info. TODO Later: should probably propose a patch for a debug option.
+sub pushd {
+	if (not defined wantarray) { carp "pushd in void context"; return }
+	croak "bad arguments to pushd" unless @_==1 && defined $_[0];
+	my $targ = abs_path(shift);
+	croak "not a directory: $targ" unless -d $targ;
+	my $orig = getcwd;
+	if ($targ ne $orig) {
+		say STDERR "\$ cd $targ";
+		chdir $targ or croak "chdir to $targ failed: $!";
+	}
+	return bless { orig=>$orig }, 'PushedDir';
+}
+sub PushedDir::DESTROY {
+	my $self = shift;
+	if (getcwd ne $self->{orig}) {
+		say STDERR "\$ cd ".$self->{orig};
+		chdir $self->{orig} or croak "chdir to ".$self->{orig}." failed: $!";
+	}
+}
+
+__END__
+
+#TODO Later: Fix the following (note setting d_getgrgid_r and d_getgrnam_r in the hints file didn't seem to help)
+warning: unresolved symbol: getgrgid
+warning: unresolved symbol: getgrnam
+warning: unresolved symbol: llvm_fma_f64
+warning: unresolved symbol: sigsuspend
+
+#TODO Later: Fix the following "miniperl make_ext.pl" errors (warnings?)
+./miniperl -Ilib make_ext.pl lib/auto/Encode/Byte/Byte.a  MAKE="make" LIBPERL_A=libperl.a LINKTYPE=static CCCDLFLAGS=
+Can't find extension Encode/Byte in any of cpan dist ext at make_ext.pl line 251.
+./miniperl -Ilib make_ext.pl lib/auto/Encode/Symbol/Symbol.a  MAKE="make" LIBPERL_A=libperl.a LINKTYPE=static CCCDLFLAGS=
+Can't find extension Encode/Symbol in any of cpan dist ext at make_ext.pl line 251.
+./miniperl -Ilib make_ext.pl lib/auto/Encode/Unicode/Unicode.a  MAKE="make" LIBPERL_A=libperl.a LINKTYPE=static CCCDLFLAGS=
+Can't find extension Encode/Unicode in any of cpan dist ext at make_ext.pl line 251.
+
--- a/build/emperl_config.sh
+++ b/build/emperl_config.sh
@ -0,0 +1,46 @@
+#!/bin/bash
+
+# This is the configuration file for building WebPerl.
+# You should edit it according to the comments below.
+# Remember to reload this file after making changes! (". emperl_config.sh")
+
+# You must edit this to point to your Emscripten SDK's emsdk_env.sh.
+. $HOME/emsdk/emsdk_env.sh
+
+# A whitespace-separated list of modules to download and add to the build.
+# Note: Cpanel::JSON::XS is required for WebPerl!
+export EMPERL_EXTENSIONS="Cpanel::JSON::XS Devel::StackTrace"
+
+# Modules from the above list that have XS code need to be linked statically.
+# Add them here, separated by whitespace (see also the "static_ext" variable
+# in https://perl5.git.perl.org/perl.git/blob/HEAD:/Porting/Glossary ).
+export EMPERL_STATIC_EXT="Cpanel/JSON/XS"
+
+# Do not edit (this gets this script's parent directory)
+BASEDIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )"/.. >/dev/null && pwd )"
+
+# Various working directories, you normally don't need to edit these
+export EMPERL_PERLSRCDIR="$BASEDIR/emperl5"
+export EMPERL_HOSTPERLDIR="$BASEDIR/work/hostperl"
+export EMPERL_DOWNLOADDIR="$BASEDIR/work/download"
+export EMPERL_OUTPUTDIR="$BASEDIR/work/outputperl"
+
+# Don't edit the following options unless you know what you're doing!
+# Note to self: In build.pl, we take advantage of the fact that on Perls >=v5.10.0, "$^V" is the same as the tag name.
+export EMPERL_PERLVER="v5.28.0"
+export EMPERL_PREFIX="/opt/perl"
+export EMPERL_PRELOAD_FILE="$EMPERL_OUTPUTDIR$EMPERL_PREFIX@$EMPERL_PREFIX"
+export EMPERL_OPTIMIZ="-O2"
+export EMPERL_LINK_FLAGS="--pre-js common_preamble.js -s EXPORTED_FUNCTIONS=['_main','_emperl_end_perl','_Perl_call_sv','_Perl_call_pv','_Perl_call_method','_Perl_call_argv','_Perl_eval_pv','_Perl_eval_sv','_webperl_eval_perl'] -s EXTRA_EXPORTED_RUNTIME_METHODS=['ccall','cwrap']"
+# Note: not including "-s SAFE_HEAP=1" in the debug flags because we're building to WebAssembly, which doesn't require alignment
+#TODO Later: Can some of the SAFE_HEAP functionality (null pointer access I think?) be replaced by the WASM error traps?
+# http://kripken.github.io/emscripten-site/docs/compiling/WebAssembly.html#binaryen-codegen-options
+export EMPERL_DEBUG_FLAGS="-s ASSERTIONS=2 -s STACK_OVERFLOW_CHECK=2"
+
+# Location and branch of the perl git repository that contains the emperl branch
+export EMPERL_PERL_REPO="https://github.com/haukex/emperl5.git"
+export EMPERL_PERL_BRANCH="emperl_$EMPERL_PERLVER"
+# Enabling this setting causes the local emperl branch to be deleted and re-fetched from the origin.
+# This is useful during development, when rewrites of the (unpublished!) git history of the branch might happen.
+export EMPERL_CLOBBER_BRANCH=0
+
--- a/build/emscripten_1.38.10_eagain.patch
+++ b/build/emscripten_1.38.10_eagain.patch
@ -0,0 +1,20 @@
+--- emscripten/src/library.js	2018-08-01 18:58:49.428051969 +0200
+++ emsdk/emscripten/1.38.10/src/library.js	2018-08-01 18:58:03.288051969 +0200
+@@ -250,7 +250,7 @@
+     // pid_t fork(void);
+     // http://pubs.opengroup.org/onlinepubs/000095399/functions/fork.html
+     // We don't support multiple processes.
+-    ___setErrNo(ERRNO_CODES.EAGAIN);
+    ___setErrNo(ERRNO_CODES.ENOTSUP);
+     return -1;
+   },
+   vfork: 'fork',
+@@ -545,7 +545,7 @@
+     // int system(const char *command);
+     // http://pubs.opengroup.org/onlinepubs/000095399/functions/system.html
+     // Can't call external programs.
+-    ___setErrNo(ERRNO_CODES.EAGAIN);
+    ___setErrNo(ERRNO_CODES.ENOTSUP);
+     return -1;
+   },
+ 
--- a/build/findtodo.sh
+++ b/build/findtodo.sh
@ -0,0 +1,24 @@
+#!/bin/bash
+set -e
+# Finds and displays TODOs for the WebPerl project.
+# the output can be piped into e.g. "less -R"
+if [ -z ${EMPERL_PERLVER+x} ]; then
+	echo "Please source emperl_config.sh first"
+	exit 1
+fi
+DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )"/.. >/dev/null && pwd )"
+TEMPFILE="`mktemp`"
+trap 'rm -f "$TEMPFILE"' EXIT
+(
+	cd "$DIR/emperl5"
+	# only look at files that have been added
+	git diff --numstat --diff-filter=A $EMPERL_PERLVER $EMPERL_PERL_BRANCH \
+		| BASEDIR=$DIR perl -wMstrict -MFile::Spec::Functions=abs2rel,rel2abs -nl0 \
+			-e '/^\d+\s+\d+\s+(.+)$/ or die $_; -e $1 and print abs2rel(rel2abs($1),$ENV{BASEDIR})'
+) >>"$TEMPFILE"
+cd $DIR
+find . -mindepth 1 \( -path ./.git -o -path ./work -o -path ./emperl5 \) -prune \
+	-o ! -name 'emperl.*' ! -type d -print0 \
+	| perl -wMstrict -MFile::Spec::Functions=canonpath -n0le 'print canonpath($_)' >>"$TEMPFILE"
+xargs -0 -a "$TEMPFILE" \
+	grep --color=always -C1 -niE '\bto.?do\b'
--- a/web/mini_ide/emscr_ide.css
+++ b/web/mini_ide/emscr_ide.css
@ -0,0 +1,36 @@
+
+/** CSS file for emscr_ide.js **/
+
+.emide {
+	font-family: Calibri, Ubuntu, "Droid Sans", Tahoma, Arial, Helvetica, sans-serif;
+}
+.CodeMirror,.code {
+	font-family: Consolas, "Ubuntu Mono", "Droid Sans Mono", "Lucida Console", "Courier New", Courier, monospace;
+}
+
+.toolbar button {
+	margin: 0 0.2em;
+}
+
+.statusbar {
+	padding: 0.2em;
+	height: 1em;
+	font-size: 10pt;
+}
+
+.filebrowser {
+	border: 1px solid black;
+	padding: 0.2em 0.5em;
+	overflow: auto;
+	height: 20em;
+}
+.fb-link { cursor:pointer; }
+.fb-link:hover  { color:#000090; background:rgba(255,255,102,0.4); }
+.fb-link:active { color:#FF0000; }
+
+.cm-resize-frame {
+	overflow: hidden;
+	resize: vertical;
+	height: 24em;
+	border: 1px solid grey;
+}
--- a/web/mini_ide/emscr_ide.js
+++ b/web/mini_ide/emscr_ide.js
@ -0,0 +1,259 @@
+"use strict";
+
+/** ***** WebPerl - http://webperl.zero-g.net *****
+ * 
+ * Copyright (c) 2018 Hauke Daempfling (haukex@zero-g.net)
+ * at the Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB),
+ * Berlin, Germany, http://www.igb-berlin.de
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the same terms as Perl 5 itself: either the GNU General Public
+ * License as published by the Free Software Foundation (either version 1,
+ * or, at your option, any later version), or the "Artistic License" which
+ * comes with Perl 5.
+ * 
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ * See the licenses for details.
+ * 
+ * You should have received a copy of the licenses along with this program.
+ * If not, see http://perldoc.perl.org/index-licence.html
+**/
+
+function make_emscr_ide (textarea, callbacks) {
+	
+	var defaulttext = "use warnings;\nuse 5.028;\nuse WebPerl qw/js/;\n\n";
+	var div = $('<div/>').addClass("emide");
+	var ide = { elem: div, cleanval: '' };
+	
+	var tb = $('<div/>').addClass("toolbar").appendTo(div);
+	var file_new = $('<button/>',{title:"New File",html:"&#x1F4C4;"}).appendTo(tb);
+	var file_upload = $('<button/>',{title:"File from Disk",html:"&#x2B06;"}).appendTo(tb);
+	var file_download = $('<button/>',{title:"Download editor contents",html:"&#x2B07;"}).appendTo(tb);
+	var file_open = $('<button/>',{title:"Open File",html:"&#x1F4C1;"}).appendTo(tb);
+	var file_save = $('<button/>',{title:"Save File",html:"&#x1F4BE;"}).appendTo(tb);
+	var file_name = $('<input/>',{title:"File Name",type:"text",size:60}).addClass("code").appendTo(tb);
+	//TODO Later: support for deleting files?
+	
+	var upload_file = $('<input/>',{type:"file"});
+	var file_up_form = $('<div/>').append(
+			$('<form/>').append( upload_file )  ).appendTo(div);
+	file_up_form.hide();
+	
+	var fbrowser = make_emscr_ide_filebrowser();
+	fbrowser.elem.hide();
+	fbrowser.elem.appendTo(div);
+	
+	var resize_frame = $('<div/>').addClass("cm-resize-frame").appendTo(div);
+	textarea.replaceWith(div);
+	resize_frame.append(textarea);
+	
+	var statusbar = $('<div/>').addClass("statusbar").appendTo(div);
+	
+	var cm = CodeMirror.fromTextArea( textarea[0], {
+			lineNumbers: true, indentWithTabs: true,
+			tabSize: 4, indentUnit: 4  });
+	ide.cm = cm;
+	/* With thanks to https://codepen.io/sakifargo/pen/KodNyR */
+	var fr = resize_frame[0];
+	var cm_resize = function() { cm.setSize(fr.clientWidth + 2, fr.clientHeight - 10); };
+	cm_resize();
+	if (window.ResizeObserver)
+		new ResizeObserver(cm_resize).observe(fr);
+	else if (window.MutationObserver)
+		new MutationObserver(cm_resize).observe(fr, {attributes: true});
+	
+	ide.isDirty = function () { return cm.getValue()!=ide.cleanval; };
+	// returns true if the user chose to abort
+	// returns false if the buffer is not dirty or the user chose to continue anyway
+	ide.dirtyCheck = function () {
+		if (ide.isDirty()) {
+			// confirm() returns true if the user clicked "OK", and false otherwise.
+			if (confirm("Unsaved changes in editor!\nContinue anyway?"))
+				return false;
+			else return true; // buffer is dirty and user chose to abort
+		}
+		else return false;
+	};
+	
+	file_new.click(function () {
+		if (ide.dirtyCheck()) return;
+		console.debug("IDE: New File");
+		file_name.val("");
+		ide.cleanval = defaulttext;
+		cm.setValue(defaulttext);
+		sessionStorage.removeItem('file_mru');
+		statusbar.text("New File");
+	});
+	
+	file_upload.click(function () {
+		if(!window.FileReader) {
+			alert("Sorry, your browser does not support file uploads.");
+			return; }
+		if (file_up_form.is(":visible")) file_up_form.hide(); else file_up_form.show();
+	});
+	upload_file.on('change', function (chgEvt) {
+		statusbar.text("");
+		file_up_form.hide();
+		if (ide.dirtyCheck()) return;
+		file_name.val("");
+		sessionStorage.removeItem('file_mru');
+		console.debug("IDE: Reading file from local disk...");
+		var reader = new FileReader();
+		reader.onload = function(loadEvt) {
+			if(loadEvt.target.readyState != 2) return;
+			if(loadEvt.target.error) {
+				alert('Error while reading file');
+				return; }
+			console.debug("IDE: File read!");
+			statusbar.text("File opened from local disk");
+			cm.setValue(loadEvt.target.result);
+		};
+		reader.readAsText(chgEvt.target.files[0]);
+	});
+	
+	file_download.click(function () {
+		var blob = new Blob([cm.getValue()],
+			{type: "text/plain;charset=utf-8"});
+		var link = document.createElement("a");
+		link.download = 'script.pl';
+		link.href = URL.createObjectURL(blob);
+		link.target = '_blank';
+		document.body.appendChild(link);
+		link.click();
+		document.body.removeChild(link);
+	});
+	
+	file_open.click(function () {
+		statusbar.text("");
+		if (!fbrowser) return;
+		if (fbrowser.isVisible()) {
+			file_open.html("&#x1F4C1;");
+			fbrowser.cancel();
+		}
+		else {
+			file_open.html("&#x1F4C2;&#x20E0;");
+			fbrowser.show(function (file) {
+				file_open.html("&#x1F4C1;");
+				if (ide.dirtyCheck()) return;
+				console.debug("IDE: Opening "+file);
+				file_name.val(file);
+				var data = FS.readFile(file,{encoding:"utf8"});
+				ide.cleanval = data;
+				cm.setValue(data);
+				sessionStorage.setItem('file_mru',file);
+				statusbar.text("Opened "+file);
+				console.debug("IDE: Opened "+file);
+				if (callbacks && callbacks.open) callbacks.open(file);
+			});
+		}
+	});
+	
+	file_save.click(function () {
+		statusbar.text("");
+		var file = file_name.val();
+		if (file.length<1) {
+			alert("Invalid File Name");
+			return; }
+		try {
+			console.debug("IDE: Trying to save "+file);
+			var data = cm.getValue();
+			FS.writeFile( file, data );
+			/* Note: The user may be saving to some location outside of the IDBFS, in which
+			 * case this syncfs call isn't really needed. But it doesn't really hurt either,
+			 * so we always do it. */
+			FS.syncfs(false, function (err) {
+				if(err) { console.error(err); alert("Saving IDBFS failed: "+err); return; }
+				statusbar.text("Saved to "+file);
+				console.debug("IDE: Saved "+file);
+				sessionStorage.setItem('file_mru',file);
+				ide.cleanval = data;
+				if (callbacks && callbacks.save) callbacks.save(file);
+			});
+		}
+		catch (err) { console.error(err); alert("Save Failed: "+err); }
+	});
+	
+	var mru_file = sessionStorage.getItem('file_mru');
+	try {
+		if (!mru_file) throw "No MRU file";
+		var data = FS.readFile( mru_file, {encoding:"utf8"} );
+		ide.cleanval = data;
+		cm.setValue(data);
+		file_name.val(mru_file);
+		console.debug("IDE: Loaded "+mru_file);
+		statusbar.text("Opened "+mru_file);
+		if (callbacks && callbacks.open) callbacks.open(mru_file);
+	}
+	catch (e) {
+		console.debug("IDE: Loading MRU failed:",e,"- falling back...");
+		file_name.val('');
+		ide.cleanval = defaulttext;
+		cm.setValue(defaulttext);
+	}
+	
+	window.addEventListener("beforeunload", function (evt) {
+		if (ide.isDirty()) {
+			var dialogText = "Unsaved changes in editor!";
+			evt.returnValue = dialogText;
+			return dialogText;
+		}
+	});
+	
+	return ide;
+}
+
+function make_emscr_ide_filebrowser() {
+	var fb = {
+		elem: $('<div/>').addClass("filebrowser"),
+		curpath: (ENV && ENV.HOME) ? ENV.HOME : FS.cwd(),
+	};
+	fb.update = function () {
+		fb.elem.empty();
+		$('<div>&#x1F4C2; </div>').addClass("fb-curdir")
+			.append(fb.curpath).appendTo(fb.elem);
+		var files = FS.readdir(fb.curpath);
+		$.each( files.sort(), function (idx,file) {
+			if (file=='.') return;
+			if (file=='..' && fb.curpath=='/') return;
+			var fullfile = FS.joinPath([fb.curpath,file]);
+			var stat = FS.stat(fullfile);
+			var icon = "&#x1F4DC;";
+			var click;
+			if (FS.isFile(stat.mode)) {
+				icon = "&#x1F4C4;";
+				click = function (evt) {
+					fb.elem.hide();
+					if(fb.callback) fb.callback(fullfile);
+					fb.callback = null;
+				};
+			}
+			else if (FS.isDir(stat.mode)) {
+				icon = file=='..'?"&#x1F4C1;&#x20D6;":"&#x1F4C1;";
+				click = function (evt) {
+					fb.curpath = fullfile;
+					fb.update();
+				};
+			}
+			else if (FS.isLink(stat.mode)) {
+				icon = "&#x1F4C4;&#x20EA;";
+			}
+			var el = $('<div>'+icon+' </div>').addClass("fb-link")
+				.append(file).appendTo(fb.elem);
+			if (click) el.click(click);
+		});
+	};
+	fb.show = function (callback) {
+		fb.callback = callback;
+		fb.elem.show();
+		fb.curpath = FS.cwd();
+		fb.update();
+	};
+	fb.cancel = function () {
+		fb.elem.hide();
+		fb.callback = null;
+	}
+	fb.isVisible = function () { return fb.elem.is(":visible") }
+	return fb;
+}
--- a/web/mini_ide/webperl_mini_ide.html
+++ b/web/mini_ide/webperl_mini_ide.html
@ -0,0 +1,244 @@
+<!doctype html>
+<html lang="en-us">
+<head>
+<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
+<title>WebPerl (IDE)</title>
+
+<!-- ----- WebPerl - http://webperl.zero-g.net -----
+
+Copyright (c) 2018 Hauke Daempfling (haukex@zero-g.net)
+at the Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB),
+Berlin, Germany, http://www.igb-berlin.de
+
+This program is free software; you can redistribute it and/or modify
+it under the same terms as Perl 5 itself: either the GNU General Public
+License as published by the Free Software Foundation (either version 1,
+or, at your option, any later version), or the "Artistic License" which
+comes with Perl 5.
+
+This program is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+See the licenses for details.
+
+You should have received a copy of the licenses along with this program.
+If not, see http://perldoc.perl.org/index-licence.html
+-->
+
+<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.39.2/codemirror.min.css" integrity="sha256-I8NyGs4wjbMuBSUE40o55W6k6P7tu/7G28/JGUUYCIs=" crossorigin="anonymous" />
+<link rel="stylesheet" type="text/css" href="emscr_ide.css" />
+<style>
+button,.text {
+	font-family: Calibri, Ubuntu, "Droid Sans", Tahoma, Arial, Helvetica, sans-serif;
+}
+pre,.code,textarea {
+	font-family: Consolas, "Ubuntu Mono", "Droid Sans Mono", "Lucida Console", "Courier New", Courier, monospace;
+}
+.fakelink {
+	color: darkblue;
+	cursor: pointer;
+}
+.border {
+	border: 1px solid black;
+	margin: 0.5em;
+	padding: 0.2em;
+}
+#evalcode_container .CodeMirror {
+	height: 4em;
+	border: 1px solid grey;
+	margin: 0.2em 0;
+}
+.output {
+	margin-top: 0.5em;
+}
+.output textarea {
+	max-width: 100%;
+}
+</style>
+
+<script src="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.39.2/codemirror.min.js" integrity="sha256-uRIJ6Wfou5cTtmcCvQNA9lvsYl8sUbZXxnfG+P79ssY=" crossorigin="anonymous"></script>
+<script src="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.39.2/mode/perl/perl.min.js" integrity="sha256-Uu9QBfi8gU6J/MzQunal8ewmY+i/BbCkBrcAXA5bcCM=" crossorigin="anonymous"></script>
+<script src="https://code.jquery.com/jquery-3.3.1.min.js" integrity="sha256-FgpCb/KJQlLNfOu91ta32o/NMZxltwRo8QtmkMRdAu8=" crossorigin="anonymous"></script>
+<script src="emscr_ide.js"></script>
+<script src="../webperl.js"></script>
+<script>
+"use strict";
+console.debug("Running our Javascript...");
+
+window.onerror = function(event) {
+	alert('Exception thrown, see JavaScript console'); };
+
+// This is a workaround for Emscripten only being able to call main() once per page load.
+// I wouldn't recommend this for "production" use.
+var baseurl = new URL(window.location);
+baseurl = baseurl.origin + baseurl.pathname.substring(0,baseurl.pathname.lastIndexOf('/'));
+function run_perl_iframe (argv, state_callback, done_callback) {
+	var html = '<html><head><base href="'+baseurl+'"><script src="webperl.js"></scr'+'ipt></head><body></body></html>';
+	var blob = new Blob([html], {type: "text/html;charset=utf-8"});
+	var src = URL.createObjectURL(blob);
+	var iframe = $('<iframe/>',{id:'Perl_IFrame',src:src}).hide().appendTo('body');
+	iframe.on('load', function() {
+		var IFramePerl = iframe[0].contentWindow['Perl'];
+		var outbuf = '';
+		IFramePerl.output = function (str) { outbuf+=str }; //TODO Later: maybe dynamic output updating is possible?
+		IFramePerl.endAfterMain = true;
+		IFramePerl.stateChanged = function (from,to) {
+			if (state_callback) state_callback(to);
+			if (from!='Ended' && to=='Ended') {
+				iframe.remove();
+				if (done_callback) done_callback(outbuf);
+			}
+		};
+		IFramePerl.init(function () {
+			window.setTimeout(function () { IFramePerl.start(argv); }, 1);
+		});
+	});
+}
+
+var eval_cm;
+$( function() {
+	console.debug("Document is ready, setting up...");
+	$('#runperl').prop("disabled",true);
+	$('#evalperl').prop("disabled",true);
+	$('#endperl').prop("disabled",true);
+	
+	var once_out_ta = Perl.makeOutputTextarea();
+	$("#once_output").append(once_out_ta);
+	$("#once_out_clear").click(function () { $(once_out_ta).val("") });
+	
+	{
+		var multirun = $('#multi_run');
+		var multirun_toggle = $('<div/>',{text:"Hide Run Multi (via IFrame)"});
+		multirun_toggle.addClass('fakelink');
+		multirun_toggle.click(function () {
+			if (multirun.is(":visible")) {
+				multirun.hide();
+				multirun_toggle.text("Show Run Multi (via IFrame)");
+			}
+			else {
+				multirun.show();
+				multirun_toggle.text("Hide Run Multi (via IFrame)");
+			}
+		});
+		multirun.before( multirun_toggle );
+	}
+	
+	// need to set up CodeMirror while #runonce is still visible (!)
+	eval_cm = CodeMirror.fromTextArea( $('#evalcode')[0], {
+		lineNumbers: true, indentWithTabs: true,
+		tabSize: 4, indentUnit: 4  });
+	{
+		var runonce = $('#runonce');
+		var runonce_toggle = $('<div/>',{text:"Show Run & Persist"});
+		runonce_toggle.addClass('fakelink');
+		runonce_toggle.click(function () {
+			if (runonce.is(":visible")) {
+				runonce.hide();
+				runonce_toggle.text("Show Run & Persist");
+			}
+			else {
+				runonce.show();
+				runonce_toggle.text("Hide Run & Persist");
+			}
+		});
+		runonce.before( runonce_toggle );
+		runonce.hide();
+	}
+	Perl.stateChanged = function (from,to) {
+		console.debug("Perl: state changed from "+from+" to "+to);
+		$('#runstate').text("State: "+to);
+		$('#runperl' ).prop("disabled", to!="Ready");
+		$('#argv'    ).prop("disabled", to!="Ready");
+		$('#evalperl').prop("disabled", to!="Running");
+		$('#endperl' ).prop("disabled", to!="Running");
+	};
+	Perl.init(final_init);
+});
+
+function final_init () { // Called when Perl goes to Ready state
+	console.debug("Final initialization steps...");
+	
+	// set up the IDE now that the Emscripten FS object is all ready to go
+	var ide = make_emscr_ide( $('textarea#ide'), {
+			open: function(file) { $('#argv,#multi_argv').val( JSON.stringify([file]) ) },
+			save: function(file) { $('#argv,#multi_argv').val( JSON.stringify([file]) ) },
+		} );
+	
+	$('#multi_runperl').click(function () {
+		if (ide.dirtyCheck()) return;
+		$('#multi_runperl').prop("disabled",true); // we *could* run multiple Perls in parallel, I just don't recommend it (memory & performance issues)
+		var argv = JSON.parse( $('#multi_argv').val() );
+		$('#multi_out_ta').text("");
+		run_perl_iframe(argv,
+			//TODO Later: the user never gets to see the "Running" state
+			function (newstate) { $('#multi_state').text("State: "+newstate) },
+			function (output) {
+				var ta = $('#multi_out_ta');
+				ta.text(output);
+				ta[0].scrollTop = ta[0].scrollHeight;
+				$('#multi_runperl').prop("disabled",false);
+			});
+	});
+	$('#runperl').click(function () {
+		if (ide.dirtyCheck()) return;
+		var argv = JSON.parse( $('#argv').val() );
+		// run Perl async so that the window has a chance to refresh
+		window.setTimeout(function () { Perl.start(argv); }, 1);
+	});
+	$('#evalperl').click(function () {
+		var rv = Perl.eval( eval_cm.getValue() );
+		console.debug('eval returned',rv);
+	});
+	$('#endperl').click(function () {
+		if (confirm("Are you sure you want to end Perl?\nYou'll have to reload the page to restart Perl."))
+			Perl.end();
+	});
+}
+</script>
+</head>
+<body>
+
+<div class="border text" style="text-align:center"><small>Really Simple Mini IDE as a Demo for <a href="http://webperl.zero-g.net" target="_blank">WebPerl</a></small></div>
+
+<div class="border">
+	<textarea id="ide" rows="24" cols="80"></textarea>
+</div>
+
+<div class="text border">
+	<div id="runonce">
+		<div>
+			<span class="code">ARGV:</span> <small>(JSON)</small>
+			<input type="text" id="argv" class="code" value='["--version"]' size="60" title="argv for perl (JSON)"/>
+			<button id="runperl" title="Run perl"><span class="code">perl</span> &#x25BA;</button>
+			<button id="endperl" title="End perl">end &#x25A0;</button>
+		</div>
+		<div class="statusbar" id="runstate">State: None</div>
+		<div>
+			<div id="evalcode_container"><textarea id="evalcode" rows="3" cols="80"></textarea></div>
+			<div><button id="evalperl" title="eval Perl code"><span class="code">eval</span> &#x25BA;</button></div>
+		</div>
+		<div class="output" id="once_output">
+			<span class="code">STDOUT and STDERR:</span> <button id="once_out_clear">Clear</button><br/>
+			<!-- output textarea will be inserted here -->
+		</div>
+	</div>
+</div>
+
+<div class="text border">
+	<div id="multi_run">
+		<div>
+			<span class="code">ARGV:</span> <small>(JSON)</small>
+			<input type="text" id="multi_argv" class="code" value='["--version"]' size="60" title="argv for perl (JSON)"/>
+			<button id="multi_runperl" title="Run perl"><span class="code">perl</span> &#x25BA;&#x25A0;</button><br/>
+			<small><i>(Remember to store code in a persistent storage like <span class="code">/mnt/idb</span>!)</i></small>
+		</div>
+		<div class="statusbar" id="multi_state">State: None</div>
+		<div class="output">
+			<span class="code">STDOUT and STDERR:</span><br/>
+			<textarea id="multi_out_ta" rows="24" cols="80" readonly></textarea>
+		</div>
+	</div>
+</div>
+
+</body>
+</html>
--- a/web/webperl.js
+++ b/web/webperl.js
@ -0,0 +1,350 @@
+"use strict";
+
+/** ***** WebPerl - http://webperl.zero-g.net *****
+ * 
+ * Copyright (c) 2018 Hauke Daempfling (haukex@zero-g.net)
+ * at the Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB),
+ * Berlin, Germany, http://www.igb-berlin.de
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the same terms as Perl 5 itself: either the GNU General Public
+ * License as published by the Free Software Foundation (either version 1,
+ * or, at your option, any later version), or the "Artistic License" which
+ * comes with Perl 5.
+ * 
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ * See the licenses for details.
+ * 
+ * You should have received a copy of the licenses along with this program.
+ * If not, see http://perldoc.perl.org/index-licence.html
+**/
+
+/** Public Interface:
+ * Perl.output       - override this for output somewhere else
+ * Perl.stateChanged - callback for state changes
+ * Perl.trace        - enables debug/trace messages
+ * Perl.endAfterMain - see exit(0) discussion below
+ * Perl.init         - initializes the Perl interpreter. Pass this function a callback to be called when init is done
+ * Perl.start        - starts up the Perl interpreter
+ * Perl.eval         - evaluates the given Perl string
+ * Perl.end          - Ends the Perl interpreter
+ * Perl.makeOutputTextarea - creates a <textarea> and redirects output there (see HTML examples)
+ */
+
+/** On our patched perlmain.c and exit(0):
+ * Since we want the Perl process to persist while the webpage is open, we've patched perlmain.c so that:
+ * 1. Global destruction and END blocks aren't triggered until explicitly requested by calling emperl_end_perl()
+ * 2. emperl_end_perl() won't actually call exit() when the exit status is zero (because Emscripten complains when you call exit() and NO_EXIT_RUNTIME is set)
+ * This has some consequences:
+ * 1. An exit(0) in the main program won't have any effect other than stopping the execution of the main program at that point, the interpreter is kept running (?)
+ * 2. ... TODO Later: Any other consequences?
+ * As a result:
+ * - Just don't call exit(0);/exit; from Perl.
+ * Note that if you want to "end" the currently running Perl, so that global destruction is performed and END blocks are executed, there are several ways to do so:
+ * - From JS, set Perl.endAfterMain before initializing Perl (this enables a "hack" that calls emperl_end_perl() after main() finishes)
+ * - From JS, call Perl.end()
+ * - From Perl, WebPerl::end_perl() (TODO Later: This doesn't cause Module.onExit to be called, right?)
+ */
+
+var Module;
+var Perl = {
+	trace: false,         // user may enable this
+	endAfterMain: false,  // user may enable this (before Perl.init)
+	// internal variables:
+	initStepsLeft: 2, // Must match number of Perl.initStepFinished() calls!
+	state: "Uninitialized",
+	readyCallback: null,
+	stdout_buf: "", stderr_buf: "", // for our default Perl.output implementation
+};
+
+/* TODO: Embedded script should be able to influence the running of Perl,
+ * the cleanest would probably be to set properties on the Perl object,
+ * such as Perl.autorun = false or Perl.argv = [...]. */
+
+window.addEventListener("load", function () {
+	// Note: to get the content of script tags with jQuery: $('script[type="text/perl"]').html()
+	var scripts = [];
+	var script_src;
+	document.querySelectorAll("script[type='text/perl']")
+		.forEach(function (el) {
+			if (el.src) {
+				if (script_src || scripts.length)
+					console.error('Only a single Perl script may be loaded via "script src=", ignoring others');
+				else
+					script_src = el.src;
+			}
+			else {
+				if (script_src)
+					console.error('Only a single Perl script may be loaded via "script src=", ignoring others');
+				else
+					scripts.push(el.innerHTML);
+			}
+		});
+	if (script_src) {
+		console.debug("Perl: Found a script with src, fetching and running...", script_src);
+		var xhr = new XMLHttpRequest();
+		xhr.addEventListener("load", function () {
+			//TODO Later: Might be nice to name the script in the virtual FS after the URL instead of a generic name
+			Perl._saveAndRun( this.responseText );
+		});
+		xhr.open("GET", script_src);
+		xhr.send();
+	}
+	else if (scripts.length) {
+		console.debug("Perl: Found",scripts.length,"embedded script(s), autorunning...");
+		//TODO: should we maybe prefix "use warnings; use 5.028;"? or at least "use WebPerl qw/js/;"?
+		Perl._saveAndRun( scripts.join(";\n") );
+	}
+	else console.debug("Perl: No embedded scripts");
+});
+Perl._saveAndRun = function (script) {
+	Perl.init(function () {
+		var file = "/tmp/scripts.pl";
+		try {
+			FS.writeFile( file, script );
+			console.debug("Perl: Saved script(s) to ",file,", now running");
+			window.addEventListener("beforeunload", function () {
+				// not really needed because we're unloading anyway, but for good measure, end Perl...
+				console.debug("Perl: beforeunload, ending...");
+				Perl.end();
+			});
+			// run Perl async so that the window has a chance to refresh
+			window.setTimeout(function () { Perl.start( [ file ] ); }, 1);
+		}
+		catch (err) { console.error("Perl:",err); alert("Save to "+file+"Failed: "+err); }
+	});
+};
+
+Perl.changeState = function (newState) {
+	var oldState = Perl.state;
+	Perl.state = newState;
+	if (Perl.stateChanged) Perl.stateChanged(oldState,newState);
+};
+Perl.stateChanged = function (from,to) { //TODO: allow multiple listeners
+	console.debug("Perl: state changed from "+from+" to "+to);
+};
+
+// chan: 1=STDOUT, 2=STDERR
+// implementations are free to ignore the "chan" argument if they want to merge the two streams
+Perl.output = function (str,chan) { // can be overridden by the user
+	var buf = chan==2 ? 'stderr_buf' : 'stdout_buf';
+	Perl[buf] += str;
+	var pos = Perl[buf].indexOf("\n");
+	while (pos>-1) {
+		console.log( chan==2?"STDERR":"STDOUT", Perl[buf].slice(0,pos) );
+		Perl[buf] = Perl[buf].slice(pos+1);
+		pos = Perl[buf].indexOf("\n");
+	}
+};
+Perl.outputLine = function (chan,text) { // internal function
+	if (arguments.length > 1) text = Array.prototype.slice.call(arguments).join(' ');
+	Perl.output(text,chan);
+	Perl.output("\n",chan);
+};
+Perl.outputChar = function (chan,c) { // internal function
+	Perl.output(String.fromCharCode(c),chan);
+};
+
+Perl.makeOutputTextarea = function (id) {
+	var ta = document.createElement('textarea');
+	if (id) ta.id = id;
+	ta.rows = 24; ta.cols = 80;
+	ta.setAttribute("readonly",true);
+	Perl.output = function (str) {
+		ta.value = ta.value + str;
+		ta.scrollTop = ta.scrollHeight;
+	};
+	return ta;
+};
+
+var getScriptURL = (function() { // with thanks to https://stackoverflow.com/a/2976714
+	var scripts = document.getElementsByTagName('script');
+	var index = scripts.length - 1;
+	var myScript = scripts[index];
+	return function() { return myScript.src; };
+})();
+
+Perl.init = function (readyCallback) {
+	if (Perl.state != "Uninitialized")
+		throw "Perl: can't call init in state "+Perl.state;
+	Perl.changeState("Initializing");
+	var baseurl = new URL(getScriptURL());
+	baseurl = baseurl.origin + baseurl.pathname.substring(0,baseurl.pathname.lastIndexOf('/'));
+	Perl.readyCallback = readyCallback;
+	Module = {
+		noInitialRun: true,
+		noExitRuntime: true,
+		print:  Perl.outputLine.bind(null,1),  printErr: Perl.outputLine.bind(null,2),
+		stdout: Perl.outputChar.bind(null,1),  stderr:   Perl.outputChar.bind(null,2),
+		stdin: function () { return null },
+		arguments: ['--version'],
+		onAbort: function () {
+			Perl.changeState("Ended");
+			console.error("Perl: Aborted (state "+Perl.state+")");
+			alert("Perl aborted");
+		},
+		onExit: function (status) { // note this may be called multiple times
+			Perl.changeState("Ended");
+			if (status==0)
+				console.info( "Perl: Exit status "+status+" (state "+Perl.state+")");
+			else {
+				console.error("Perl: Exit status "+status+" (state "+Perl.state+")");
+				alert("Perl exited with exit status "+status+" in state "+Perl.state);
+			}
+		},
+		onRuntimeInitialized: function () {
+			console.debug("Perl: Module.onRuntimeInitialized");
+			Perl.initStepFinished();
+		},
+		preRun: [
+			function () {
+				console.debug("Perl: doing preRun, fetching IndexDB filesystem...");
+				try { FS.mkdir('/mnt'); } catch(e) {}
+				try { FS.mkdir('/mnt/idb'); } catch(e) {}
+				FS.mount(IDBFS, {} ,'/mnt/idb');
+				FS.syncfs(true, function (err) {
+					if (err) { console.error("Perl:",err); alert("Perl: Loading IDBFS failed: "+err); return; }
+					console.debug("Perl: IndexDB filesystem ready");
+					Perl.initStepFinished();
+				});
+			}
+		],
+		locateFile: function (file) {
+			var wasmRe = /\.(wast|wasm|asm\.js|data)$/;
+			if (wasmRe.exec(file))
+				return baseurl+"/"+file;
+			return file;
+		},
+	};
+	if (Perl.endAfterMain) {
+		Module.preRun.push(function () {
+			// patch _main so that afterwards we call emperl_end_perl
+			var origMain = Module._main;
+			Module._main = function() {
+				origMain.apply(this, arguments);
+				console.debug("Perl: main() has ended, ending perl...");
+				var status = ccall("emperl_end_perl","number",[],[]);
+				if (status==0) {
+					// we know that in this case, there is no event thrown to us (since exit() isn't called)
+					// so we have to transition states manually
+					Module.onExit(status);
+				}
+				return status;
+			};
+		});
+	}
+	console.debug("Perl: Fetching Emscripten/Perl...");
+	var script = document.createElement('script');
+	script.async = true; script.defer = true;
+	script.src = baseurl+"/emperl.js";
+	document.getElementsByTagName('head')[0].appendChild(script);
+};
+
+Perl.initStepFinished = function () {
+	if (Perl.state!="Initializing" || Perl.initStepsLeft<1)
+		throw "Perl: internal error: can't call initStepFinished in state "+Perl.state+" ("+Perl.initStepsLeft+")";
+	if (--Perl.initStepsLeft) {
+		console.debug("Perl: One init step done, but "+Perl.initStepsLeft+" steps left, waiting...");
+		return;
+	} else console.debug("Perl: All init steps done, doing final initialization...");
+	
+	/* NOTE: Apparently, when NO_EXIT_RUNTIME is set, and exit() is called from the main program
+	 * (from Module.callMain), Emscripten doesn't report this back to us via an ExitStatus exception
+	 * like it does from ccall - it doesn't even call the addOnExit/ATEXIT or addOnPostRun/ATPOSTRUN
+	 * handlers! So at the moment, the only reliable way I've found to catch the program exit()ing
+	 * is to patch into Emscripten's (undocumented!) Module.quit... */
+	var origQuit = Module.quit;
+	Module.quit = function (status, exception) {
+		console.debug("Perl: quit with",exception);
+		Module.onExit(status);
+		origQuit(status,exception);
+	}
+	
+	Perl.changeState("Ready");
+	if (Perl.readyCallback) Perl.readyCallback();
+	Perl.readyCallback = null;
+};
+
+Perl.start = function (argv) {
+	if (Perl.state!="Ready")
+		throw "Perl: can't call start in state "+Perl.state;
+	Perl.changeState("Running");
+	try {
+		// Note: currently callMain doesn't seem to throw ExitStatus exceptions, see discussion in Perl.initStepFinished
+		Module.callMain(argv ? argv : Module.arguments);
+	}
+	catch (e) {
+		if (e instanceof ExitStatus) {
+			console.debug("Perl: start:",e);
+			Module.onExit(e.status);
+		} else throw e;
+	}
+};
+
+Perl.eval = function (code) {
+	if (Perl.state!="Running")
+		throw "Perl: can't call eval in state "+Perl.state;
+	if (Perl.trace) console.debug('Perl: ccall webperl_eval_perl',code);
+	try {
+		return ccall("webperl_eval_perl","string",["string"],[code]);
+	}
+	catch (e) {
+		if (e instanceof ExitStatus) {
+			// the code caused perl to (try to) exit - now we need to call
+			// Perl's global destruction via our emperl_end_perl() function
+			Perl.end(); //TODO: Perl.end has already been called at this point (how?)
+		} else throw e;
+	}
+};
+
+/* Note that Emscripten apparently doesn't support re-running the program once it exits (?).
+ * So at the moment, once we end Perl, that's it. The only useful effect of ending Perl is
+ * that global destruction is executed and END blocks are called. But since a user may leave
+ * a webpage at any moment without warning, WebPerl scripts should not rely on normal termination! */
+Perl.end = function () {
+	if (Perl.state!="Running") {
+		if (Perl.state=="Ended") {
+			console.warn("Perl: end called when already Ended");
+			return;
+		}
+		else throw "Perl: can't call end in state "+Perl.state;
+	}
+	else Perl.changeState("Ended");
+	try {
+		ccall("emperl_end_perl","number",[],[]);
+	}
+	catch (e) {
+		if (e instanceof ExitStatus) {
+			console.debug("Perl: end: ",e);
+			Module.onExit(e.status);
+		} else throw e;
+	}
+};
+
+Perl.next_glue_id = 0;
+Perl.GlueTable = {};
+Perl._glue_free_ids = {};
+Perl.glue = function (ref) {
+	var id;
+	var free_ids = Object.keys(Perl._glue_free_ids);
+	if (free_ids.length>0) {
+		id = free_ids[0];
+		delete Perl._glue_free_ids[id];
+		if (Perl.trace) console.debug('Perl: Glue reused id',id,'to',ref);
+	}
+	else {
+		if (Perl.next_glue_id>=Number.MAX_SAFE_INTEGER)
+			throw "Perl.GlueTable is overflowing!"
+		id = ''+(Perl.next_glue_id++);
+		if (Perl.trace) console.debug('Perl: Glue id',id,'to',ref);
+	}
+	Perl.GlueTable[id] = ref;
+	return id;
+}
+Perl.unglue = function (id) {
+	if (Perl.trace) console.debug('Perl: Unglue id',id,'from',Perl.GlueTable[id]);
+	delete Perl.GlueTable[id];
+	Perl._glue_free_ids[id]=1;
+}
--- a/web/webperl.psgi
+++ b/web/webperl.psgi
@ -0,0 +1,31 @@
+#!/usr/bin/env perl
+use warnings;
+use 5.0.26;
+use FindBin;
+use Plack::MIME;
+use Plack::Builder qw/builder enable mount/;
+use Plack::App::Directory ();
+
+# Demo Plack server for WebPerl
+# run me with "plackup webperl.psgi"
+
+# in an Apache .htaccess file, one could say:
+#AddType application/javascript .js
+#AddType application/octet-stream .data .mem
+#AddType application/wasm .wasm
+
+Plack::MIME->add_type(".js"   => "application/javascript");
+Plack::MIME->add_type(".data" => "application/octet-stream");
+Plack::MIME->add_type(".mem"  => "application/octet-stream");
+Plack::MIME->add_type(".wasm" => "application/wasm");
+
+my $SERV_ROOT = $FindBin::Bin;
+
+builder {
+	enable 'SimpleLogger';
+	enable 'Static',
+		path => qr/\.(?:html?|js|css|data|mem|wasm|pl)\z/i,
+		root => $SERV_ROOT;
+	Plack::App::Directory->new({root=>$SERV_ROOT})->to_app;
+}
+
--- a/web/webperl_demo.html
+++ b/web/webperl_demo.html
@ -0,0 +1,78 @@
+<!doctype html>
+<html lang="en-us">
+<head>
+<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
+<title>WebPerl &lt;script&gt; Demos</title>
+
+<script src="webperl.js"></script>
+
+<!-- It's possible to load a single script like this:
+
+<script type="text/perl" src="foo.pl"></script>
+
+but then only a single <script type="text/perl"> tag is allowed in the
+document, because there is only a single Perl interpreter.
+
+If you use multiple <script type="text/perl"> tags like below, they are
+concatenated into a single script and then run.
+
+If you don't have any such script tags in the document, Perl won't be
+run automatically, and you can control Perl in detail via the JS "Perl"
+object provided by webperl.js (more control over output redirection, set
+command line arguments, etc.). Most of this functionality is
+demonstrated in the included "mini IDE".
+-->
+
+<!-- Example 1: A really basic script -->
+<script type="text/perl">
+print "Hello, Perl World!\n";
+</script>
+
+<!-- Example 2: Accessing JavaScript -->
+<script type="text/perl">
+use warnings;
+use strict;
+use WebPerl qw/js/;
+
+js('document')->getElementById('my_button')
+	->addEventListener("click", sub {
+		print "You clicked 'Testing!'\n";
+	} );
+
+</script>
+
+<!-- Example 3: Using jQuery -->
+<script src="https://code.jquery.com/jquery-3.3.1.min.js" integrity="sha256-FgpCb/KJQlLNfOu91ta32o/NMZxltwRo8QtmkMRdAu8=" crossorigin="anonymous"></script>
+<script type="text/perl">
+use warnings;
+use strict;
+use WebPerl qw/js/;
+
+my $jq = js('jQuery');
+my $btn = $jq->('<button>', { text=>"Click me!" } );
+$btn->click(sub {
+	print "You clicked the jQuery button!\n";
+} );
+$btn->appendTo( $jq->('#buttons') );
+</script>
+
+<!-- Optional STDOUT/STDERR text area (if you don't use this, output goes to Javascript console) -->
+<script>
+window.addEventListener("load", function () {
+	document.getElementById('output')
+		.appendChild( Perl.makeOutputTextarea() );
+});
+</script>
+
+</head>
+<body>
+
+<p>This is a demo of <a href="http://webperl.zero-g.net" target="_blank">WebPerl</a>!</p>
+
+<div id="output"></div>
+<div id="buttons">
+	<button id="my_button">Testing!</button>
+</div>
+
+</body>
+</html>