Add a little support for installation into a venv

Add instructions for installing into a venv

README.md

@@ -89,6 +89,56 @@ that are needed by pysol from source (without the debian modifications).
 Please uninstall that package and use the cardsets archive from sourceforge.net
 per the instructions above.
 
+### Installing from source and running in a python venv (virtual environment)
+
+At the moment, this only works on POSIX (Linux, FreeBSD and similar) systems.
+Windows and Mac users - you'll need to chip in with a script for your system.
+
+#### 1 - Install build prerequisites: six and random2
+
+This is kind of stupid and maybe it can be fixed in the future, but for now:
+
+```
+pip install six
+pip install random2
+```
+
+You may want to use your OS distribution package system instead, for example:
+
+```
+sudo apt-get install python-six
+sudo apt-get install python-random2
+```
+
+#### 2 - Clone the source from version control
+
+```
+git clone git://github.com/shlomif/PySolFC.git
+cd PySolFC
+```
+
+#### 3 - Create your virtual environment.
+
+```
+PKGDIR=/usr/local/packages/PySolFC # or whatever
+export PKGDIR
+mkdir -p $PKGDIR
+( cd $PKGDIR && python -m venv ./env )
+```
+
+#### 4 - Run the install script
+
+```
+./contrib/install-pysolfc.sh
+```
+
+#### 5 - Put cardsets into place as above.
+
+#### 6 - Enjoy playing
+
+$PKGDIR/env/bin/pysol.py
+
+
 ## Alternate toolkit.
 
 - Python2 (2.7 or later)

contrib/install-pysolfc.sh

@@ -0,0 +1,14 @@
+#! /bin/sh -Cefu
+
+: ${PKGTREE:=/usr/local/packages/PySolFC}
+PIP=$(printf '%s/env/bin/pip install --no-binary :all: ' $PKGTREE)
+PYPROG=$(printf '%s/env/bin/python' $PKGTREE)
+VERSION=$(env PYTHONPATH=`pwd` $PYPROG -c 'from pysollib.settings import VERSION ; print(VERSION)' )
+XZBALL=$(printf 'dist/PySolFC-%s.tar.xz' $VERSION)
+REQS='six random2 pillow'
+
+make dist
+for req in $REQS ; do
+    $PIP $req
+done
+$PIP --upgrade $XZBALL

pysollib/util.py

@@ -24,6 +24,7 @@
 # imports
 import sys
 import os
+import site
 
 # PySol imports
 from pysollib.settings import DATA_DIRS, TOOLKIT
@@ -100,6 +101,11 @@ class DataLoader:
         path.append(os.path.join(sys.path[0], "pysollib", "data"))
         # from settings.py
         path.extend(DATA_DIRS)
+        # itz 2018-10-21 in case of venv installation
+        # (or even homedir installation), path[0] will be quite wrong.
+        # Just directly use the location where setup.py puts the data.
+        if site.PREFIXES:
+            path.append(os.path.join(site.PREFIXES[0], 'share', 'PySolFC'))
         # check path for valid directories
         self.path = []
         for p in path: