Allow specifying a comparison function for Search::Dict::look().

p4raw-id: //depot/perl@11483

1 files changed, 32 insertions, 13 deletions

diff --git a/lib/Search/Dict.pm b/lib/Search/Dict.pm
index 58c7543ced..18c676b3e1 100644
--- a/lib/Search/Dict.pm
+++ b/lib/Search/Dict.pm
@@ -4,7 +4,7 @@ require Exporter;
 
 use strict;
 
-our $VERSION = '1.00';
+our $VERSION = '1.01';
 our @ISA = qw(Exporter);
 our @EXPORT = qw(look);
 
@@ -15,7 +15,7 @@ Search::Dict, look - search for key in dictionary file
 =head1 SYNOPSIS
 
     use Search::Dict;
-    look *FILEHANDLE, $key, $dict, $fold;
+    look *FILEHANDLE, $key, $dict, $fold, $comp;
 
 =head1 DESCRIPTION
 
@@ -26,38 +26,57 @@ occurs.
 The flags specify dictionary order and case folding:
 
 If I<$dict> is true, search by dictionary order (ignore anything but word
-characters and whitespace).
+characters and whitespace).  The default is honour all characters.
 
-If I<$fold> is true, ignore case.
+If I<$fold> is true, ignore case.  The default is to honour case.
+
+If I<$comp> is defined, use that as a reference to the comparison subroutine,
+which must return less than zero, zero, or greater than zero, if the
+first comparand is less than, equal, or greater than the second comparand.
+
+If there are only three arguments and the third argument is a hash
+reference, the keys of that hash can have values C<dict>, C<fold>, and
+C<comp>, and their correponding values will be used as the parameters.
 
 =cut
 
 sub look {
-    my($fh,$key,$dict,$fold) = @_;
+    my($fh,$key,$dict,$fold,$comp) = @_;
+    if (@_ == 3 && ref $dict eq 'HASH') {
+	my $opt = $dict;
+	$dict = 0;
+	$dict = $opt->{dict} if exists $opt->{dict};
+	$fold = $opt->{fold} if exists $opt->{fold};
+	$comp = $opt->{comp} if exists $opt->{comp};
+    }
+    $comp = sub { $_[0] cmp $_[1] } unless defined $comp;
     local($_);
     my(@stat) = stat($fh)
 	or return -1;
     my($size, $blksize) = @stat[7,11];
     $blksize ||= 8192;
     $key =~ s/[^\w\s]//g if $dict;
-    $key = lc $key if $fold;
-    my($min, $max, $mid) = (0, int($size / $blksize));
+    $key = lc $key       if $fold;
+    # find the right block
+    my($min, $max) = (0, int($size / $blksize));
+    my $mid;
     while ($max - $min > 1) {
 	$mid = int(($max + $min) / 2);
 	seek($fh, $mid * $blksize, 0)
 	    or return -1;
 	<$fh> if $mid;			# probably a partial line
 	$_ = <$fh>;
-	chop;
+	chomp;
 	s/[^\w\s]//g if $dict;
-	$_ = lc $_ if $fold;
-	if (defined($_) && $_ lt $key) {
+	$_ = lc $_   if $fold;
+	if (defined($_) && $comp->($_, $key) < 0) {
 	    $min = $mid;
 	}
 	else {
 	    $max = $mid;
 	}
     }
+    # find the right line
     $min *= $blksize;
     seek($fh,$min,0)
 	or return -1;
@@ -66,10 +85,10 @@ sub look {
 	$min = tell($fh);
 	defined($_ = <$fh>)
 	    or last;
-	chop;
+	chomp;
 	s/[^\w\s]//g if $dict;
-	$_ = lc $_ if $fold;
-	last if $_ ge $key;
+	$_ = lc $_   if $fold;
+	last if $comp->($_, $key) >= 0;
     }
     seek($fh,$min,0);
     $min;