+2013-12-25 Tassilo Horn <tsdh@gnu.org>
+
+ * control.texi (Pattern matching case statement): Rephrase lexical
+ binding requirement: the example needs it, not `pcase' itself.
+
2013-12-25 Chong Yidong <cyd@gnu.org>
* eval.texi (Eval): Document the LEXICAL arg to eval.
@code{(pred numberp)} is a pattern that simply checks that @code{exp}
is a number, and @code{_} is the catch-all pattern that matches anything.
+Note that the the lambda being the result of the @code{fn} clause is a
+closure (@pxref{Closures}), so the file defining @code{evaluate} must
+have lexical binding enabled (@pxref{Using Lexical Binding}, for how
+to enable it).
+
Here are some sample programs including their evaluation results:
@example
(evaluate '(add 1 2) nil) ;=> 3
(evaluate '(add x y) '((x . 1) (y . 2))) ;=> 3
(evaluate '(call (fn x (add 1 x)) 2) nil) ;=> 3
-(evaluate '(sub 1 2) nil) ;=> (error "Unknown expression (sub 1 2)")
+(evaluate '(sub 1 2) nil) ;=> error
@end example
-Note that (parts of) @code{pcase} only work as expected with lexical
-binding, so lisp files using @code{pcase} should have enable it
-(@pxref{Using Lexical Binding}, for how to enable lexical binding).
-
There are two kinds of patterns involved in @code{pcase}, called
@emph{U-patterns} and @emph{Q-patterns}. The @var{upattern} mentioned above
are U-patterns and can take the following forms: