From b38773bd020c745cf2b40a87a18ac10174ecc4c2 Mon Sep 17 00:00:00 2001
From: Roger Bell_West <roger@firedrake.org>
Date: Mon, 2 Sep 2019 09:47:55 +0100
Subject: Challenge 24 solutions.

---
 challenge-024/roger-bell-west/ch-1-notes.txt |  9 ++++
 challenge-024/roger-bell-west/perl5/ch-1.pl  |  1 +
 challenge-024/roger-bell-west/perl5/ch-2.pl  | 73 ++++++++++++++++++++++++++++
 challenge-024/roger-bell-west/perl6/ch-1.p6  |  1 +
 4 files changed, 84 insertions(+)
 create mode 100644 challenge-024/roger-bell-west/ch-1-notes.txt
 create mode 100644 challenge-024/roger-bell-west/perl5/ch-1.pl
 create mode 100755 challenge-024/roger-bell-west/perl5/ch-2.pl
 create mode 100755 challenge-024/roger-bell-west/perl6/ch-1.p6

diff --git a/challenge-024/roger-bell-west/ch-1-notes.txt b/challenge-024/roger-bell-west/ch-1-notes.txt
new file mode 100644
index 0000000000..52b092e920
--- /dev/null
+++ b/challenge-024/roger-bell-west/ch-1-notes.txt
@@ -0,0 +1,9 @@
+This assumes that the script must be directly executable (./ch-1.pl etc.).
+
+If one can invoke the interpreter separately, then a zero-length file
+is readily usable with perl5, perl6 _and_ GhostScript.
+
+>z
+perl z
+perl6 z
+gs -- z
diff --git a/challenge-024/roger-bell-west/perl5/ch-1.pl b/challenge-024/roger-bell-west/perl5/ch-1.pl
new file mode 100644
index 0000000000..061674ea6f
--- /dev/null
+++ b/challenge-024/roger-bell-west/perl5/ch-1.pl
@@ -0,0 +1 @@
+#! /usr/bin/perl
diff --git a/challenge-024/roger-bell-west/perl5/ch-2.pl b/challenge-024/roger-bell-west/perl5/ch-2.pl
new file mode 100755
index 0000000000..372da02c38
--- /dev/null
+++ b/challenge-024/roger-bell-west/perl5/ch-2.pl
@@ -0,0 +1,73 @@
+#! /usr/bin/perl
+
+use strict;
+use warnings;
+
+my $i=Local::InvIndex->new;
+foreach my $file (@ARGV) {
+  $i->add_doc_file($file);
+}
+my $w=$i->search('chimney');
+foreach my $result (@{$w}) {
+  print join(' ',@{$result}),"\n";
+}
+
+package Local::InvIndex;
+use Lingua::Stem;
+
+sub new {
+  my $class=shift;
+  my $self={};
+  bless $self,$class;
+  $self->{stemmer}=Lingua::Stem->new();
+  $self->{stemmer}->stem_caching({-level => 2});
+  $self->{index}={};
+  return $self;
+}
+
+sub add_doc_string {
+  my $self=shift;
+  my $docname=shift;
+  my @words;
+  my @indices;
+  my $line=0;
+  foreach my $str (@_) {
+    my @l=split /\n/,$str;
+    foreach my $l (@l) {
+      my @w=$self->splitline($l);
+      push @indices,map {[$docname,$line,$_]} (0..$#w);
+      push @words,@w;
+      $line++;
+    }
+  }
+  $self->{stemmer}->stem_in_place(@words);
+  foreach my $i (0..$#words) {
+    push @{$self->{index}{$words[$i]}},$indices[$i];
+  }
+}
+
+sub add_doc_file {
+  my $self=shift;
+  my $filename=shift;
+  my $buf;
+  open I,'<',$filename or die "Can't open filename\n";
+  while (<I>) {
+    $buf.=$_;
+  }
+  close I;
+  $self->add_doc_string($filename,$buf);
+}
+
+sub search {
+  my $self=shift;
+  my @search=shift;
+  $self->{stemmer}->stem_in_place(@search);
+  return $self->{index}{$search[0]} || [];
+}
+
+sub splitline {
+  my $self=shift;
+  my $line=shift;
+  $line =~ s/[^A-za-z ]+/ /g;
+  return grep /./,split ' ',lc($line);
+}
diff --git a/challenge-024/roger-bell-west/perl6/ch-1.p6 b/challenge-024/roger-bell-west/perl6/ch-1.p6
new file mode 100755
index 0000000000..f96b32e61c
--- /dev/null
+++ b/challenge-024/roger-bell-west/perl6/ch-1.p6
@@ -0,0 +1 @@
+#! /usr/bin/perl6
-- 
cgit