NetNews Usenet Archive 1992 #30/NN_1992_30.iso/spool/comp/lang/perl/7555

Internet Message Format | 1992-12-21 | 1.7 KB

Path: sparky!uunet!nestroy.wu-wien.ac.at!dec4.wu-wien.ac.at!neumann
From: [e-mail] (Gustaf Neumann)
Newsgroups: comp.lang.perl
Subject: Re: In 5.0, are we gonna get...
Date: Fri, 18 Dec 92 20:10:07 MET
Organization: WU-Wien
Lines: 38
Distribution: world
Message-ID: <[e-mail]>
References: <[e-mail]> <[e-mail]> <[e-mail]> <[e-mail]> <[e-mail]>
NNTP-Posting-Host: dec4.wu-wien.ac.at

In article <[e-mail]> from [Fri, 18 Dec 1992 14:01:12 GMT] you wrote:
 |>
 |>   I would like to write:
 |>
 |>     $max = reduce { $a >  $b ? $a : $b } @row
 |>
 |> -- Another idea would be to have a reduce in array-context,
 |>    for example to squeeze out adjacent equal elements:
 |>
 |>      @uniq = reduce { ($a eq $b) ? ($a) : ($a,$b) } @row
 |>
 |>    Here the ab-sub is evaluated in array-context. The first time
 |>    $a is the first element of @row, later on the last element
 |>    of the partial result.

this examples are still pretty trivial in current perl:

sub reduce {
    local($f,@array) = @_;
    local($a) = shift @array;

    return $a unless @array;
    local($b) = &red($f,@array);
    return eval $f;
}

print &reduce('$a >  $b ? $a : $b',1,6,5,8,3,4),"\n";
print &reduce('$a <  $b ? $a : $b',1,6,5,8,3,4),"\n";
print &reduce('$a + $b',1,6,5,8,3,4),"\n";

your array examples are more tricky.
-gustaf
--
Gustaf Neumann          [e-mail], [e-mail]
Vienna University of Economics and Business Administration
Augasse 2-6,  A-1090 Vienna, Austria
Tel: [phone] x4533      Fax: 347-555