\input texinfo @c -*-texinfo-*-
@setfilename ../../info/cl
@settitle Common Lisp Extensions
+@documentencoding UTF-8
@include emacsver.texi
@copying
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.3 or
any later version published by the Free Software Foundation; with no
-Invariant Sections, with the Front-Cover texts being ``A GNU Manual'',
+Invariant Sections, with the Front-Cover Texts being ``A GNU Manual'',
and with the Back-Cover Texts as in (a) below. A copy of the license
is included in the section entitled ``GNU Free Documentation License''.
must be a list of the form @samp{(@var{name} @var{arglist}
@var{forms}@dots{})}, which defines a function exactly as if
it were a @code{cl-defun} form. The function @var{name} is defined
-accordingly for the duration of the body of the @code{cl-flet}; then
-the old function definition, or lack thereof, is restored.
-
-You can use @code{cl-flet} to disable or modify the behavior of
-functions (including Emacs primitives) in a temporary, localized fashion.
-(Compare this with the idea of advising functions.
-@xref{Advising Functions,,,elisp,GNU Emacs Lisp Reference Manual}.)
+accordingly but only within the body of the @code{cl-flet}, hiding any external
+definition if applicable.
The bindings are lexical in scope. This means that all references to
the named functions must appear physically within the body of the
themselves in @code{nil} blocks.
@end defmac
+@c FIXME? Maybe this should be in a separate section?
+@defmac cl-tagbody &rest labels-or-statements
+This macro executes statements while allowing for control transfer to
+user-defined labels. Each element of @var{labels-or-statements} can
+be either a label (an integer or a symbol), or a cons-cell
+(a statement). This distinction is made before macroexpansion.
+Statements are executed in sequence, discarding any return value.
+Any statement can transfer control at any time to the statements that follow
+one of the labels with the special form @code{(go @var{label})}.
+Labels have lexical scope and dynamic extent.
+@end defmac
+
+
@node Iteration
@section Iteration
@end defmac
@defmac cl-the type form
-Type information provided by @code{cl-the} is ignored in this package;
-in other words, @code{(cl-the @var{type} @var{form})} is equivalent to
-@var{form}. Future byte-compiler optimizations may make use of this
-information.
+@code{cl-the} returns the value of @code{form}, first checking (if
+optimization settings permit) that it is of type @code{type}. Future
+byte-compiler optimizations may also make use of this information to
+improve runtime efficiency.
For example, @code{mapcar} can map over both lists and arrays. It is
hard for the compiler to expand @code{mapcar} into an in-line loop
Except as noted, the @code{cl-defstruct} facility of this package is
entirely compatible with that of Common Lisp.
+The @code{cl-defstruct} package also provides a few structure
+introspection functions.
+
+@defun cl-struct-sequence-type struct-type
+This function returns the underlying data structure for
+@code{struct-type}, which is a symbol. It returns @code{vector} or
+@code{list}, or @code{nil} if @code{struct-type} is not actually a
+structure.
+@end defun
+
+@defun cl-struct-slot-info struct-type
+This function returns a list of slot descriptors for structure
+@code{struct-type}. Each entry in the list is @code{(name . opts)},
+where @code{name} is the name of the slot and @code{opts} is the list
+of slot options given to @code{defstruct}. Dummy entries represent
+the slots used for the struct name and that are skipped to implement
+@code{:initial-offset}.
+@end defun
+
+@defun cl-struct-slot-offset struct-type slot-name
+Return the offset of slot @code{slot-name} in @code{struct-type}. The
+returned zero-based slot index is relative to the start of the
+structure data type and is adjusted for any structure name and
+:initial-offset slots. Signal error if struct @code{struct-type} does
+not contain @code{slot-name}.
+@end defun
+
+@defun cl-struct-slot-value struct-type slot-name inst
+Return the value of slot @code{slot-name} in @code{inst} of
+@code{struct-type}. @code{struct} and @code{slot-name} are symbols.
+@code{inst} is a structure instance. This routine is also a
+@code{setf} place. Can signal the same errors as @code{cl-struct-slot-offset}.
+@end defun
+
@node Assertions
@chapter Assertions and Errors