INCLUDE-BOOK

Major Section:  EVENTS

Examples:
(include-book "my-arith")
(include-book "/home/smith/my-arith")
(include-book "/../../my-arith")


General Form:
(include-book file :load-compiled-file action  ; [default :warn]
                   :uncertified-okp t/nil      ; [default t]
                   :defaxioms-okp t/nil        ; [default t]
                   :skip-proofs-okp t/nil      ; [default t]
                   :dir directory
                   :doc doc-string)

where file is a book name. See books for general information, see book-name for information about book names, and see pathname for information about file names. Action is one of t, nil, :warn (the default), :try, or :comp; these values are explained below. The first three -okp keyword arguments, which default to t, determine whether errors or warnings are generated under certain conditions explained below; when the argument is t, warnings are generated. The dir argument, if supplied, is a keyword that represents an absolute pathname for a directory (see pathname), to be used instead of the current book directory (see cbd) for resolving the given file argument to an absolute pathname. In particular, :dir :system resolves file using the distributed books/ directory of your installation, unless your ACL2 executable was built somewhere other than where it currently resides; please see the ``BOOKS DIRECTORY, AND SOUNDNESS WARNING'' below. To define other keywords that can be used for dir, see add-include-book-dir. Doc-string is an optional documentation string; see doc-string. If the book has no certificate, if its certificate is invalid or if the certificate was produced by a different version of ACL2, a warning is printed and the book is included anyway; see certificate. This can lead to serious errors; see uncertified-books. If the portcullis of the certificate (see portcullis) cannot be raised in the host logical world, an error is caused and no change occurs to the logic. Otherwise, the non-local events in file are assumed. Then the keep of the certificate is checked to ensure that the correct files were read; see keep. A warning is printed if uncertified books were included. Even if no warning is printed, include-book places a burden on you; see certificate.

If there is a compiled file for the book that was created more recently than the book itself and the value action of the :load-compiled-file argument is not nil, or is omitted, then the compiled file is automatically loaded; otherwise it is not loaded. If action is t then the compiled file must be loaded or an error will occur; if action is :warn (the default) then a warning will be printed; if action is :try then no warning will be printed; and if action is :comp then the file will be immediately compiled (if the compiled file does not already exist) and loaded. Certify-book can also be used to compile a book. The effect of compilation is to speed up the execution of the functions defined within the book when those functions are applied to specific values. The presence of compiled code for the functions in the book should not otherwise affect the performance of ACL2. See guard for a discussion. NOTE: the :load-compiled-file argument is not recursive; that is, calls of include-book that are inside the book supplied to include-book will use their own :load-compiled-file arguments (default :warn), not the :load-compiled-file argument for the enclosing book.

The three -okp arguments, :uncertified-okp, defaxioms-okp, and skip-proofs-okp, determine the system's behavior when the book or any subbook is found to be uncertified, when the book or any subbook is found to contain defaxiom events, and when the book or any subbook is found to contain skip-proofs events, respectively. All three default to t, which means it is ``ok'' for the condition to arise. In this case, a warning is printed but the processing to load the book is allowed to proceed. When one of these arguments is nil and the corresponding condition arises, an error is signaled and processing is aborted. Exception: :uncertified-okp is ignored if the include-book is being performed on behalf of a certify-book.

Include-book is similar in spirit to encapsulate in that it is a single event that ``contains'' other events, in this case the events listed in the file named. Include-book processes the non-local event forms in the file, assuming that each is admissible. Local events in the file are ignored. You may use include-book to load multiple books, creating the logical world that contains the definitions and theorems of all of them.

If any non-local event of the book attempts to define a name that has already been defined -- and the book's definition is not syntactically identical to the existing definition -- the attempt to include the book fails, an error message is printed, and no change to the logical world occurs. See redundant-events for the details.

When a book is included, the default defun-mode (see default-defun-mode) for the first event is always :logic. That is, the default defun-mode ``outside'' the book -- in the environment in which include-book was called -- is irrelevant to the book. Events that change the defun-mode are permitted within a book (provided they are not in local forms). However, such changes within a book are not exported, i.e., at the conclusion of an include-book, the ``outside'' default defun-mode is always the same as it was before the include-book.

Unlike every other event in ACL2, include-book puts a burden on you. Used improperly, include-book can be unsound in the sense that it can create an inconsistent extension of a consistent logical world. A certification mechanism is available to help you carry this burden -- but it must be understood up front that even certification is no guarantee against inconsistency here. The fundamental problem is one of file system security. See certificate for a discussion of the security issues.

After execution of an include-book form, the value of acl2-defaults-table is restored to what it was immediately before that include-book form was executed. See acl2-defaults-table.

BOOKS DIRECTORY, AND SOUNDNESS WARNING.

We refer to the ``books directory'' of an executable image as the full pathname string of the books directory associated with :dir :system for that image. This is where the distributed books directory should reside. By default, it is the books/ subdirectory of the directory where the sources reside and the executable image is thus built. However, the Makefile provided with ACL2 contains a variable ACL2_BOOKS_DIR that may be set to the intended books directory. Advanced users who want to modify the books directory without using the Makefile can look at the calls of initialize-acl2 therein. For example, if the distributed books are to be moved to /usr/local/lib/, a manual build on Windows without using the Makefile might conclude as follows.

(save-acl2 (quote (initialize-acl2 (quote include-book) 
                                   *acl2-pass-2-files*
                                   "/usr/local/lib/"))
           "saved_acl2.bat")

The Soundness Warning is this: You must avoid using two executable images with different books directories in the same project, if there are any include-book forms with :dir :system in that collection of books. Otherwise, unsoundness may occur. (We may enforce this restriction in later versions of ACL2.) Here is an example.

Suppose we certify a book book1 using an executable with books directory dir1, where this book contains the definition (defun foo () 1). Suppose that book book2 contains these forms:

; book2
(in-package "ACL2")
(include-book "book1" :dir :system)
(defthm thm1 (equal (foo) 1))

Now let us certify this book1 and book2 (see certify-book). But now suppose we have another executable image, this time with a different books directory dir2, where dir2 also contains a book named book1, but where this new book1 contains the definition (defun foo () 2). If we execute (include-book "book2" :dir :system) using the second executable, we will be including the latter definition of foo from the latter book1 together with the above-displayed theorem thm1, and hence we can trivially prove nil!

We conclude the Soundness Warning by noting that even if you use a single executable image, :dir :system will not work for you if you move the books from their original location, unless care was taken to specify the final location when the image was built as indicated in the discussion of the Makefile and initialize-acl2 above.

This concludes the guided tour through books. See set-compile-fns for a subtle point about the interaction between include-book and on-the-fly compilation. See certify-book for a discussion of how to certify a book.

:cited-by Programming