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Logtalk - Object oriented extension to Prolog
Release 2.21.6

Copyright (c) 1998-2004 Paulo Moura.  All Rights Reserved.
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Installing Logtalk is just a matter of decompressing the downloaded archive 
and copying the resulting directory to a suitable location.

The Logtalk directory can reside in any user accessible location. 
This location depends on the working environment and on the number of users.
The "misc" sub-directory contains some shell scripts for easy installation 
of Logtalk on Windows, Unix, and Unix-like operating systems (for details, 
see the misc/NOTES file).


INSTALLING FOR A SINGLE USER

In the case of a single user, the Logtalk directory may simply be copied to 
the user home directory.


INSTALLING FOR MULTIPLE USERS

In the case of multiple users, the Logtalk directory can be copied to any 
location that its accessible by all the users (assuming that copying the 
Logtalk directory to each user home directory is not feasible or desired).

Regarding directory and file permissions, it is advisable to make all files 
read-only in order to avoid user tempering. However, the library and examples 
sub-directories (and possibly the compiler sub-directory, depending on the 
chosen Prolog compiler) must be user writable as compiling Logtalk source 
files generates intermediate Prolog files, which are written to the same 
location as the source files. However, making directories world-writable is a 
security risk. One solution is to copy the Logtalk xml, examples, and library 
directories to each user home directory (the "misc" sub-directory contains 
some scripts which may be called by the end-users for making these copies).


ENVIRONMENT VARIABLES

It is recommended that you define an environment variable named LOGTALKHOME 
pointing to the Logtalk installation directory for use with your Prolog 
compilers. In addition, you may want to add the Logtalk sub-directory "xml",
which contains useful scripts for processing XML documenting files, to your 
execution path.

* Unix and Unix-like systems:

If you use a csh shell, add the following line to your ~/.cshrc file:

	setenv LOGTALKHOME /your/installation/directory/lgt2216
	setenv PATH $PATH:$LOGTALKHOME/xml:$LOGTALKHOME/misc

If you use a bash shell, add the following lines to your ~/.profile file:

	LOGTALKHOME=/your/installation/directory/lgt2216
	export LOGTALKHOME
	PATH=$PATH:$LOGTALKHOME/xml:$LOGTALKHOME/misc
	export PATH

When using the provided shell script for installing Logtalk, a symbolic link 
to the Logtalk installation directory is automatically created. The link is 
named "logtalk". In this case, you may use this symbolic link to define the 
environment variable in order to avoid breaking it when upgrading Logtalk.

* Windows systems:

In Windows 95/98/ME, environment variables are defined in the autoexec.bat 
file (you will need to reboot after editing the file):

	SET LOGTALKHOME=C:\your\installation\folder\

In Windows NT/2000/XP, environment variables are defined using the System 
properties control panel (if you are a system administrator, you should use 
the JScript install script provided in the "misc" sub-directory).


CUSTOMIZING PROLOG CONFIGURATION FILES

Logtalk interfaces with a specific Prolog compiler via a configuration file 
that can be found on the $LOGTALKHOME/configs directory. These configuration 
files can be customized by changing the values of the default flags and 
compiler options which are used by Logtalk when compiling source files. For 
a full description of these default flags and compiler options, consult the 
"Running and debugging Logtalk programs" section of the User Manual. Some of 
the default flags that you may want to change are: "portability", "altdirs", 
"underscore_vars", "startup_message", "smart_compilation", and the set of 
documentation-related flags ("xml", "xsl", "xmlspec", and "doctype"). Be sure 
to read the $LOGTALKHOME/configs/NOTES file for Prolog specific notes; some 
Prolog compilers do not support the whole range of compilation flags.  


CREATING NEW PROLOG TOP-LEVELS FOR AUTOMATIC LOADING OF LOGTALK

Most Prolog compilers allows the user to define an initialization file that 
is automatically consulted at startup. This initialization file may contain 
directives for loading other files, such as the Logtalk configuration file 
and the Logtalk compiler. The "misc" sub-directory contains several scripts 
for automating the creation of these initialization files for some Prolog 
compilers. In addition, be sure to read the configs/NOTES file notes on the 
Prolog compilers that you intend to use.