pdlua -- a Lua embedding for Pd
Copyright (C) 2007,2008,2009,2013 Claude Heiland-Allen <claude@mathr.co.uk>
Copyright (C) 2012 Martin Peach martin.peach@sympatico.ca


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 2
of the License, 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.


Current maintainer: Albert Gräf <aggraef@gmail.com>
This source is available on GitHub: https://github.com/agraef/pd-lua

pdlua works with all Pd flavors out there and makes Pd external programming
incredibly easy (please check the included examples and the tutorial in the
corresponding subdirectories). Originally written by Claude Heiland-Allen,
pdlua has gone through the hands of a few people over the years, including
mrpeach (maintainer since 2011), zmoelnig a.k.a. umlaeute (loader update,
Debian package), and myself (Arch package, Lua 5.3+ support, Purr Data and
plugdata support, pdx.lua live-coding extension, tutorial). Please also check
my brief account on the history of pd-lua below.

Lua 5.4 is highly recommended with the latest version, Lua 5.3 works as
well. Reportedly, Lua 5.2 and even 5.1 still work (at least to some extent),
but I haven't tested these myself for quite a while, so you may run into
problems with these old versions - use at your own risk.

If you haven't used pdlua before, please make sure to check the included
tutorial first. See:

https://agraef.github.io/pd-lua/tutorial/pd-lua-intro.html

This contains a fairly gentle introduction to pdlua, walks you through the
creation of a basic example, and then goes on to cover most major features of
pdlua, including the special facilities for tables, clocks, receivers, signal
processing, graphics, and live-coding, in quite some detail. This will be
helpful when embarking on your own projects, or trying to make sense of the
included examples.


History and Credits:

pdlua was originally written by Claude Heiland-Allen, with contributions by
Frank Barknecht and Martin Peach, according to the original source.
Please check Claude's website at https://mathr.co.uk/, and
https://mathr.co.uk/blog/lua.html for Lua-related content on his blog
(including pdlua's original announcement).

Martin Peach took over maintenance of pdlua in 2011, you can find that part of
the history in Pd's old svn repository at SourceForge, including IOhannes
Zmölnig's loader update for Pd 0.47. See
https://sourceforge.net/p/pure-data/svn/HEAD/tree/trunk/externals/loaders/pdlua/

The present source is a fork of umlaeute's 0.7.3 version in the Debian package
repository at https://anonscm.debian.org/git/pkg-multimedia/pd-lua.git, which
in turn was based on the 0.7.3 version of pdlua in Pd's svn repository.

The current version (0.8 and later) is actively maintained by Albert Gräf,
with contributions by many people: Claude Heiland-Allen (Lua 5.4 update,
bugfixes), Alexandre Porres (documentation updates), sebshader (relative path
loading), Timothy Schoen (plugdata compatibility, signal and graphics
support), and Ben Wesch (multi-channel signal support, Deken tests and uploads
on GitHub). This is also the version included in Purr Data
(https://github.com/agraef/purr-data) and Timothy Schoen's plugdata
(https://github.com/plugdata-team/plugdata).

Please file bugs and requests at https://github.com/agraef/pd-lua. I maintain
a lot of packages and thus it may take a while at times, but I look at all the
bug reports and pull requests, and try to respond to them eventually. :)


Ready-Made Packages:

The latest vanilla binaries for Ubuntu, Mac, and Windows can always be found
on https://github.com/agraef/pd-lua (but see below for the Deken package).
Also, both Purr Data and plugdata ship with pdlua, and have it enabled by
default, so no 3rd party package is needed in those environments.

For vanilla Pd, we recommend installing the Deken package (named `pdlua`),
readily available using Pd's `Find externals` menu option. This package was
originally uploaded by Alexandre Porres, but Ben Wesch recently added Deken
tests and uploads to our GitHub workflow, so that the Deken releases are now
automatized and always in sync with the GitHub releases. Thanks, Ben!

pd-lua is also in the Arch repositories (maintained by dvzrv, thanks David!),
and in the Debian repositories (maintained by IOhannes Zmölnig, thanks
umlaeute!). (During busy times, these may trail our releases for a little bit,
but most of the time they will the latest version.)

Mac users please note that the packages I distribute aren't notarized, so on
recent macOS versions you'll have to jump through the usual hoops to make them
usable. Running `xattr -rd com.apple.quarantine` on pdlua.pd_darwin should
usually do the trick, but check the internet for up-to-date information on
Gatekeeper for details.


Enabling pdlua:

Again, this step is only necessary with vanilla Pd; both Purr Data and
plugdata have the pdlua loader enabled by default, so it should be ready to go
immediately.

With vanilla Pd, after installing pdlua, the pdlua loader also needs to be
added to your startup libraries, before Pd will recognize any Lua object in
your patches. This only needs to be done once. (Alternatively, you can also
use the `-lib pdlua` option on the Pd command line, or a `declare -lib pdlua`
object in a patch with Lua objects.) To make any of this work, you may also
have to add the parent directory of the `pdlua` folder to Pd's search path if
pdlua was installed in an unusual location.


Compilation Instructions:

You can also compile pdlua yourself from source, which isn't hard to do.

The source should compile out of the box on (at least) Linux, macOS and
Windows, just make sure that you have Lua and Pd installed and run
`make`. pdlua uses pd-lib-builder by Katja Vetter as its build system, please
check https://github.com/pure-data/pd-lib-builder and the included
Makefile.pdlibbuilder for details.

pdlua works with any reasonably modern Pd flavour, but pd-lib-builder will
look for vanilla Pd (http://msp.ucsd.edu/software.html). So you'll need to
have that installed, or be prepared to adjust the Makefile accordingly.

If you compile from git sources and use the included lua submodule (see
Compilation from Git Sources below), then only Pd will be needed. Otherwise
you'll also have to install Lua (https://www.lua.org).

The following build environments on various platforms are known to work and
are supported.

Linux: Uses gcc and GNU make. Pd and Lua should be available in your package
repositories. If not then it's easy to install them from source.

Mac: Uses Xcode. The build requires that you have the Pd header files
somewhere under /Applications/Pd-*/Contents/Resources/src (which should be the
case if you're running a recent Pd distribution by MSP); otherwise you can set
the `PDINCLUDEDIR` make variable accordingly. Lua is available, e.g., in
Homebrew (https://brew.sh/).

Windows: Uses msys2/mingw (https://www.msys2.org/), which is the Windows
incarnation of gcc and GNU make. The build assumes that you have a recent Pd
installation as distributed by MSP, so that the header files and pd.dll are
found during compilation and linkage, respectively. Lua is available in msys2.


Compilation from Git Sources:

The repository source includes a lua submodule which can be used to compile
Lua alongside pdlua, so no Lua installation is needed to compile the
external. (You'll still need to have Pd installed.) Just make sure to check
out the submodule with the repository (`git clone --recurse-submodules`).
If you already checked out the repository, you can also do `git submodule
update --init` instead. This should get you a fairly recent revision of the
upstream Lua source.

Once the lua submodule is checked out, you can just run `make` as usual, it
will use the submodule to compile Lua alongside the pdlua module. The
resulting binary will be statically linked with the Lua interpreter.

Also note that on the Mac you can build a universal (a.k.a. arm64+x86_64)
binary this way, using `arch="arm64 x86_64"` when running `make`. This will
work best if Lua is compiled alongside pdlua, since installed Lua libraries
may not be universal binaries (in Homebrew at least they aren't).

Otherwise, if the lua submodule isn't checked out, `make` will try
`pkg-config` to locate an existing Lua installation on your system and link
against that.


Installation:

After a successful compile, you can go about installing the external with the
usual `make install` which copies the external to its own directory named
pdlua. This should generally do something sensible on each of the supported
platforms. Note that the installation may require root privileges.

Linux: By default, installation goes into /usr/local/lib/pd-externals, which
should be one of the directories on Pd's built-in search path.

Mac: Installation goes into ~/Library/Pd by default. Move the pdlua folder to
/Library/Pd for a system-wide installation.

Windows/mingw: Installation goes into the Pd subdirectory of your %APPDATA%
folder by default. Move the pdlua folder to the extra folder of Pd in your
ProgramFiles directory for a system-wide installation.

In any case, it's possible to override the default installation directory
using the PDLIBDIR variable. E.g., on Linux you can install into Pd's
/usr/lib/pd/extra folder as follows:

    make install PDLIBDIR=/usr/lib/pd/extra

It's generally advisable to do a staged install using `DESTDIR` first so that
you can review the installation directory layout beforehand and adjust it if
needed. To these ends, run `make install`, e.g., as follows:

    make install DESTDIR=./build

It is possible to use DESTDIR along with PDLIBDIR.

Another possibility is to run `make install objectsdir=./build` which creates
the `pdlua` folder directly in the `build` directory from where you can move
it to any location on Pd's library search path that you see fit. (This option
is considered deprecated, but it's still the most convenient for a quick
manual installation.)