@cindex searching for strings
@cindex finding strings
@cindex strings, searching for
-Searches @var{in} for an occurrence of @var{find}. If it occurs, the
-value is @var{find}; otherwise, the value is empty. You can use this
-function in a conditional to test for the presence of a specific
-substring in a given string. Thus, the two examples,
+Searches the string @var{in} for an occurrence of the string @var{find}. If
+it occurs, the result is @var{find}; otherwise, the result is the empty
+string. You can use this function in a conditional to test for the presence
+of a specific substring in a given string. These two examples:
@example
-$(findstring a,a b c)
-$(findstring a,b c)
+$(findstring lo Wo,Hello World!)
+$(findstring lo Wo,World Hello!)
@end example
@noindent
-produce the values @samp{a} and @samp{} (the empty string),
-respectively. @xref{Testing Flags}, for a practical application of
-@code{findstring}.
+expand to @samp{lo Wo} and @samp{} (the empty string), respectively.
+@xref{Testing Flags}, for a practical application of @code{findstring}.
@need 750
+@item $(filter @var{pattern}@dots{},@var{text})
@findex filter
@cindex filtering words
@cindex words, filtering
-@item $(filter @var{pattern}@dots{},@var{text})
Returns all whitespace-separated words in @var{text} that @emph{do} match
any of the @var{pattern} words, removing any words that @emph{do not}
match. Each word in @var{pattern} is compared to every word in @var{text}