The Guile License
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The license of Guile consists of the GNU GPL plus a special statement giving blanket permission to link with non-free software.  This is the license statement as found in any individual file that it applies to:

     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, 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 software; see the file COPYING.  If not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

     As a special exception, the Free Software Foundation gives permission for additional uses of the text contained in its release of GUILE.

     The exception is that, if you link the GUILE library with other files to produce an executable, this does not by itself cause the resulting executable to be covered by the GNU General Public License.  Your use of that executable is in no way restricted on account of linking the GUILE library code into it.

     This exception does not however invalidate any other reasons why the executable file might be covered by the GNU General Public License.

     This exception applies only to the code released by the Free Software Foundation under the name GUILE.  If you copy code from other Free Software Foundation releases into a copy of GUILE, as the General Public License permits, the exception does not apply to the code that you add in this way.  To avoid misleading anyone as to the status of such modified files, you must delete this exception notice from them.

     If you write modifications of your own for GUILE, it is your choice whether to permit this exception to apply to your modifications.  If you do not wish that, delete this exception notice.

Layout of this Manual
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The manual is divided into five parts.

Part I: Introduction to Guile provides an overview of what Guile is and how you can use it.  A whirlwind tour shows how Guile can be used interactively and as a script interpreter, how to link Guile into your own applications, and how to write modules of interpreted and compiled code for use with Guile.  Everything introduced here is documented again and in full by the later parts of the manual.  This part also explains how to obtain and install new versions of Guile, and how to report bugs effectively.

Part II: Writing and Running Guile Scheme and Part III: Programming with Guile document all aspects of practical programming using Guile.  This covers both the Scheme level --- where we provide an introduction to the key ideas of the Scheme language --- and use of Guile's scm interface to write new primitives and objects in C, and to incorporate Guile into a C application.  It also covers the use of Guile as a POSIX compliant script interpreter, and how to use the Guile debugger.

Part IV: Guile API Reference documents Guile's core API.  Most of the variables and procedures in Guile's core programming interface are available in both Scheme and C, and are related systematically such that the C interface can be inferred from the Scheme interface and vice versa.  Therefore this part of the manual documents the Guile API in functionality-based groups with the Scheme and C interfaces presented side by side.  Where the Scheme and C interfaces for a particular functional area do differ --- which is sometimes inevitable, given the differences in the structure of the two languages --- this is pointed out and explained.  In all cases the overriding principle is that all the reference documentation for a given functional area is grouped together.

Part V: Guile Modules describes some important modules, distributed as part of the Guile distribution, that extend the functionality provided by the Guile Scheme core.  Two important examples are:

  * the POSIX module, which provides Scheme level procedures for system and network programming that conform to the POSIX standard

  * the SLIB module, which makes Aubrey Jaffer's portable Scheme library available for use in Guile.

Conventions used in this Manual
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We use some conventions in this manual.

  * For some procedures, notably type predicates, we use iff to mean `if and only if'.  The construct is usually something like: `Return VAL iff CONDITION', where VAL is usually `#t' or `non-#f'.  This typically means that VAL is returned if CONDITION holds, and that #f is returned otherwise.

  * In examples and procedure descriptions and all other places where the evaluation of Scheme expression is shown, we use some notation for denoting the output and evaluation results of expressions.

     The symbol => is used to tell which value is returned by an evaluation:

          (+ 1 2)
          =>
          3

     Some procedures produce some output besides returning a value.  This is denoted by the symbol -|.

          (begin (display 1) (newline) 'hooray)
          -| 1
          =>
          hooray