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; * doc/lispref/control.texi (Conditionals): Document SYMBOL form.

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Sean Whitton
2025-10-07 17:35:32 +01:00
parent da47fa2f23
commit f3c29c1415
1 changed files with 18 additions and 6 deletions
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doc/lispref/control.texi
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@@ -330,7 +330,10 @@ Each element of @code{varlist} has the form @w{@code{(@var{symbol}
locally bound to the result. Bindings are sequential, as in @code{let*}
(@pxref{Local Variables}). If only the test result of @var{value-form}
is of interest, use @code{_} for @var{symbol}. Then @var{value-form} is
evaluated and checked for @code{nil}, but its value is not bound.
evaluated and checked for @code{nil}, but its value is not bound. As a
special case, an entry of @code{varlist} may be of the form just
@code{@var{symbol}}, which means to check the current binding of symbol
for @code{nil}.
@end defmac
@defmac when-let* varlist then-forms...
@@ -342,9 +345,12 @@ form in @var{then-forms}.
@code{varlist} has the form @w{@code{(@var{symbol} @var{value-form})}},
in which @var{value-form} is evaluated and @var{symbol} is locally bound
to the result. Bindings are sequential, as in @code{let*} (@pxref{Local
Variables}). If only the test result of @var{value-form}
is of interest, use @code{_} for @var{symbol}. Then @var{value-form} is
evaluated and checked for @code{nil}, but its value is not bound.
Variables}). If only the test result of @var{value-form} is of
interest, use @code{_} for @var{symbol}. Then @var{value-form} is
evaluated and checked for @code{nil}, but its value is not bound. As a
special case, an entry of @code{varlist} may be of the form just
@code{@var{symbol}}, which means to check the current binding of symbol
for @code{nil}.
@end defmac
@defmac and-let* varlist then-forms...
@@ -359,7 +365,10 @@ in which @var{value-form} is evaluated and @var{symbol} is locally bound
to the result. Bindings are sequential, as in @code{let*} (@pxref{Local
Variables}). If only the test result of @var{value-form} is of
interest, use @code{_} for @var{symbol}. Then @var{value-form} is
evaluated and checked for @code{nil}, but its value is not bound.
evaluated and checked for @code{nil}, but its value is not bound. As a
special case, an entry of @code{varlist} may be of the form just
@code{@var{symbol}}, which means to check the current binding of symbol
for @code{nil}.
@end defmac
Some Lisp programmers follow the convention that @code{and} and
@@ -383,7 +392,10 @@ in which @var{value-form} is evaluated and @var{symbol} is locally bound
to the result. Bindings are sequential, as in @code{let*} (@pxref{Local
Variables}). If only the test result of @var{value-form} is of
interest, use @code{_} for @var{symbol}. Then @var{value-form} is
evaluated and checked for @code{nil}, but its value is not bound.
evaluated and checked for @code{nil}, but its value is not bound. As a
special case, an entry of @code{varlist} may be of the form just
@code{@var{symbol}}, which means to check the current binding of symbol
for @code{nil}.
The return value of @code{while-let} is always @code{nil}.
@end defmac