* Backquote:: Easier construction of list structure.
* Problems with Macros:: Don't evaluate the macro arguments too many times.
Don't hide the user's variables.
+* Indenting Macros:: Specifying how to indent macro calls.
@end menu
@node Simple Macro
called interactively.
@end defspec
+ The body of the macro definition can include a @code{declare} form,
+which can specify how @key{TAB} should indent macro calls, and how to
+step through them for Edebug.
+
+@defspec declare @var{specs}...
+This special form is used at top level in a macro definition to
+specify various additional information about it. Two kinds of
+specification are currently supported:
+
+@table @code
+@item (edebug @var{edebug-form-spec})
+Specify how to step through macro calls for Edebug.
+@xref{Instrumenting Macro Calls}, for more details.
+
+@item (indent @var{indent-spec})
+Specify how to indent calls to this macro. @xref{Indenting Macros},
+for more details.
+@end table
+@end defspec
+
+ No macro absolutely needs a @code{declare} form, because that form
+has no effect on how the macro expands, on what the macro means in the
+program. It only affects secondary features: indentation and Edebug.
+
@node Backquote
@section Backquote
@cindex backquote (list substitution)
allocation construct. You wouldn't use @code{setcar} on a constant such
as @code{'(nil)}, so naturally you won't use it on @code{(empty-object)}
either.
+
+@node Indenting Macros
+@section Indenting Macros
+
+ You can use the @code{declare} form in the macro definition to
+specify how to @key{TAB} should indent indent calls to the macro. You
+write it like this:
+
+@example
+(declare (indent @var{indent-spec}))
+@end example
+
+@noindent
+Here are the possibilities for @var{indent-spec}:
+
+@table @asis
+@item @code{nil}
+This is the same as no property---use the standard indentation pattern.
+@item @code{defun}
+Handle this function like a @samp{def} construct: treat the second
+line as the start of a @dfn{body}.
+@item a number, @var{number}
+The first @var{number} arguments of the function are
+@dfn{distinguished} arguments; the rest are considered the body
+of the expression. A line in the expression is indented according to
+whether the first argument on it is distinguished or not. If the
+argument is part of the body, the line is indented @code{lisp-body-indent}
+more columns than the open-parenthesis starting the containing
+expression. If the argument is distinguished and is either the first
+or second argument, it is indented @emph{twice} that many extra columns.
+If the argument is distinguished and not the first or second argument,
+the line uses the standard pattern.
+@item a symbol, @var{symbol}
+@var{symbol} should be a function name; that function is called to
+calculate the indentation of a line within this expression. The
+function receives two arguments:
+@table @asis
+@item @var{state}
+The value returned by @code{parse-partial-sexp} (a Lisp primitive for
+indentation and nesting computation) when it parses up to the
+beginning of this line.
+@item @var{pos}
+The position at which the line being indented begins.
+@end table
+@noindent
+It should return either a number, which is the number of columns of
+indentation for that line, or a list whose car is such a number. The
+difference between returning a number and returning a list is that a
+number says that all following lines at the same nesting level should
+be indented just like this one; a list says that following lines might
+call for different indentations. This makes a difference when the
+indentation is being computed by @kbd{C-M-q}; if the value is a
+number, @kbd{C-M-q} need not recalculate indentation for the following
+lines until the end of the list.
+@end table