#!/usr/bin/perl -w
#
# Multi-language sentence splitter.
#
# For help, enter `./split-sentences.pl -h`
#
# Example usage:
# echo "This is a test. This is more." | ./split-sentences.pl -l en
#
# Expected output is one sentence per line. That is, newlines are
# inserted after the end of each sentence. The -l en flag uses English
# language period-punctuation rules.
#
# Derived from the moses-smt (Moses Statistica Machine Translation)
# sentece splitter; modified slightly for our needs.
#
# moses-smt and this file is licensed under the LGPLv2.1
# (Lesser GNU Public License Version 2.1)
# Based on Preprocessor written by Philipp Koehn
binmode(STDIN, ":utf8");
binmode(STDOUT, ":utf8");
binmode(STDERR, ":utf8");
use FindBin qw($RealBin);
use strict;
use utf8;
my $mydir = "$RealBin/nonbreaking_prefixes";
my %NONBREAKING_PREFIX = ();
my $language = "en";
my $hanzi = 1;
my $QUIET = 0;
my $HELP = 0;
while (@ARGV) {
$_ = shift;
/^-l$/ && ($language = shift, next);
/^-q$/ && ($QUIET = 1, next);
/^-h$/ && ($HELP = 1, next);
}
if ($HELP) {
print "Usage ./split-sentences.perl (-l [en|de|...]) < textfile > splitfile\n";
exit;
}
# Specifying `-l zh` or `-l yue` will pad each and every hanzi
# character with whitespace. Specifying `-l zh-pre` or `-l yue-pre`
# implies that the input text is pre-split into words, and whitespace
# is not added. In either case, splitting into sentences is still
# performed.
if ($language =~ /-pre$/) {
$language =~ s/-pre//;
$hanzi = 0;
}
if (!$QUIET) {
print STDERR "Sentence Splitter v3\n";
print STDERR "Language: $language\n";
}
my $prefixfile = "$mydir/nonbreaking_prefix.$language";
# Default to English if we don't have a language-specific prefix file.
if (!(-e $prefixfile)) {
$prefixfile = "$mydir/nonbreaking_prefix.en";
print STDERR "WARNING: No known abbreviations for language '$language', attempting fall-back to English version...\n";
die ("ERROR: No abbreviations files found in $mydir\n") unless (-e $prefixfile);
}
if (-e "$prefixfile") {
open(PREFIX, "<:utf8", "$prefixfile") or die "Cannot open: $!";
while (<PREFIX>) {
my $item = $_;
chomp($item);
if (($item) && (substr($item,0,1) ne "#")) {
if ($item =~ /(.*)[\s]+(\#NUMERIC_ONLY\#)/) {
$NONBREAKING_PREFIX{$1} = 2;
} else {
$NONBREAKING_PREFIX{$item} = 1;
}
}
}
close(PREFIX);
}
##loop text, add lines together until we get a blank line or a <p>
my $text = "";
while(<STDIN>) {
chop;
# Punt on lines containing stray ISO-8859 chars
if (utf8::valid($_) != 1) { next; }
if (/^<.+>$/ || /^\s*$/) {
# time to process this block, we've hit a blank or <p>
&do_it_for($text,$_);
# print "<P>\n" if (/^\s*$/ && $text); ##if we have text followed by <P>
$text = "";
}
else {
#append the text, with a space
$text .= $_. " ";
}
}
#do the leftover text
&do_it_for($text,"") if $text;
sub do_it_for {
my($text,$markup) = @_;
print &preprocess($text) if $text;
print "$markup\n" if ($markup =~ /^<.+>$/);
#chop($text);
}
sub preprocess
{
# This is one paragraph.
my($text) = @_;
# Get rid of stray html markup.
$text =~ s/<P>//g;
# Double-dashes, without spaces! sometimes get used to concatenate
# sentences. I see this in Project Gutenberg books a lot.
$text =~ s/--/ -- /g;
# Clean up spaces at head and tail of each line as well as any
# double-spacing. Get rid of carriage returns.
$text =~ s/\r//g;
$text =~ s/ +/ /g;
$text =~ s/\n /\n/g;
$text =~ s/ \n/\n/g;
$text =~ s/^ //g;
$text =~ s/ $//g;
##### Add sentence breaks as needed. #####
# Non-period end of sentence markers (?!) followed by sentence starters.
$text =~ s/([?!]) +([\'\"\(\[\¿\¡\p{IsPi}]*[\p{IsUpper}])/$1\n$2/g;
# Multi-dots followed by sentence starters.
$text =~ s/(\.[\.]+) +([\'\"\(\[\¿\¡\p{IsPi}]*[\p{IsUpper}])/$1\n$2/g;
# A period, followed by a footnote.[42] followed by sentence starters.
# Can be [HarvardStyle42] also.
$text =~ s/([\.?!][\'\"\)]?\[.*?]) +([\'\"\(\[\¿\¡\p{IsPi}]*[\p{IsUpper}])/$1\n$2/g;
# Add breaks for sentences that end with some sort of punctuation
# inside a quote or parenthetical and are followed by a possible
# sentence starter punctuation and upper case.
$text =~ s/([?!\.][\ ]*[\'\"\)\]\p{IsPf}]+) +([\'\"\(\[\¿\¡\p{IsPi}]*[\ ]*[\p{IsUpper}])/$1\n$2/g;
# Add breaks for sentences that end with some sort of punctuation
# are followed by a sentence starter punctuation and upper case.
# This differs from above in that starter punctuation is mandatory,
# and thus we can take the period, here, too.
$text =~ s/([?!\.]) +([\'\"\(\[\¿\¡\p{IsPi}]+[\ ]*[\p{IsUpper}])/$1\n$2/g;
# Sentences that end in punctuation, followed by a double-dash.
$text =~ s/([?!\.]) +(--[ \'\"\(\[\¿\¡\p{IsPi}]*[\p{IsUpper}])/$1\n$2/g;
# Sentences that end in punctuation, followed by one or more
# underscores. These are typically used to denote _emphasized text_.
$text =~ s/([?!\.]) *(_+[ \'\"\(\[\¿\¡\p{IsPi}]*[\p{IsUpper}])/$1\n$2/g;
# Sentence-ending punctuation, followed by optional close-quote.
$text =~ s/([。．？！♪]”?)/$1\n/g;
$text =~ s/([\.?!]) *(\p{InCJK})/$1\n$2/g;
if ($hanzi) { $text =~ s/(\p{InCJK})/ $1 /g; }
$text =~ s/ +/ /g;
# Special punctuation cases are covered. Check all remaining periods.
my $word;
my $i;
my @words = split(/ /,$text);
$text = "";
for ($i=0; $i<(scalar(@words)-1); $i++)
{
if ($words[$i] =~ /([\p{IsAlnum}\.\-]*)([\'\"\)\]\%\p{IsPf}]*)(\.+)$/)
{
# Check if $1 is a known honorific and $2 is empty, never break.
my $prefix = $1;
my $starting_punct = $2;
if ($prefix && $NONBREAKING_PREFIX{$prefix} &&
$NONBREAKING_PREFIX{$prefix} == 1 &&
!$starting_punct)
{
# Not breaking;
}
elsif ($words[$i] =~ /(\.)[\p{IsUpper}\-]+(\.+)$/)
{
# Not breaking - upper case acronym
}
elsif($words[$i+1] =~ /^([ ]*[\'\"\(\[\¿\¡\p{IsPi}]*[ ]*[\p{IsUpper}0-9])/)
{
# The next word has a bunch of initial quotes, maybe a
# space, then either upper case or a number
$words[$i] = $words[$i]."\n" unless ($prefix && $NONBREAKING_PREFIX{$prefix} && $NONBREAKING_PREFIX{$prefix} == 2 && !$starting_punct && ($words[$i+1] =~ /^[0-9]+/));
#we always add a return for these unless we have a numeric non-breaker and a number start
}
}
$text = $text.$words[$i]." ";
}
# We stopped one token from the end to allow for easy look-ahead.
# Append it now.
$text = $text.$words[$i];
# Clean up spaces at head and tail of each line as well as any
# double-spacing
$text =~ s/ +/ /g;
$text =~ s/\n /\n/g;
$text =~ s/ \n/\n/g;
$text =~ s/^ //g;
$text =~ s/ $//g;
# Add trailing break.
$text .= "\n" unless $text =~ /\n$/;
return $text;
}