4 files changed, 24 insertions, 9 deletions

diff --git a/scripts/MarkdownBook/Book.pm b/scripts/MarkdownBook/Book.pm
index a3d9eeb..f942803 100644
--- a/scripts/MarkdownBook/Book.pm
+++ b/scripts/MarkdownBook/Book.pm
@@ -16,6 +16,8 @@
 use strict;
 use warnings;
 
+use Carp;
+
 package MarkdownBook::Book;
 
 sub new
@@ -36,6 +38,8 @@ sub new
 		use MarkdownBook::Document::Txt;
 		$self->{'format'} = 'txt';
 		$self->{'format_mod'} = 'Txt';
+	} else {
+		croak('Unsupported format "' . $format . '"');
 	}
 
 	$self->{'dir'} = $dir;
@@ -114,7 +118,8 @@ sub create_documents
 
 	# Create chapter documents.
 	$i = 0;
-	open($series_fh, '<', $self->{'dir'} . '/chapters');
+	open($series_fh, '<', $self->{'dir'} . '/chapters')
+		or croak('Cannot open chapters file');
 	while (<$series_fh>) {
 		chomp($_);
 		($file, $title) = split(/[ \t]+/, $_, 2);
@@ -131,7 +136,8 @@ sub create_documents
 	$i = -1;
 	@letters = ('A' .. 'Z');
 	if (-e $self->{'dir'} . '/appendices') {
-		open($series_fh, '<', $self->{'dir'} . '/apendices');
+		open($series_fh, '<', $self->{'dir'} . '/apendices')
+			or croak('Cannot open appendices file');
 		while (<$series_fh>) {
 			chomp($_);
 			($file, $title) = split(/[ \t]+/, $_, 2);
@@ -194,11 +200,14 @@ sub _do_subst_macro
 	if ($macro eq 'toc') {
 		return $self->_do_gen_toc();
 	} elsif ($macro eq 'sectlink') {
-		die('Invalid arguments to "sectlink" macro') if @args != 1;
-		$sec = $self->{'sections_by_id'}->{$args[0]};
-		return '[§ ' . $sec->number() . '][' . $sec->id() . ']';
+		if (@args != 1) {
+			carp('Invalid arguments to "sectlink" macro');
+		} else {
+			$sec = $self->{'sections_by_id'}->{$args[0]};
+			return '[§ ' . $sec->number() . '][' . $sec->id() . ']';
+		}
 	} else {
-		die("Unrecognized macro \"$macro\"");
+		carp("Unrecognized macro \"$macro\"");
 	}
 }
 
diff --git a/scripts/MarkdownBook/Document.pm b/scripts/MarkdownBook/Document.pm
index b84503d..fa47cdb 100644
--- a/scripts/MarkdownBook/Document.pm
+++ b/scripts/MarkdownBook/Document.pm
@@ -17,6 +17,7 @@ use strict;
 use warnings;
 
 use MarkdownBook::Section;
+use Carp;
 
 package MarkdownBook::Document;
 
@@ -143,7 +144,8 @@ sub parse
 	my $source_text;
 
 	open($source_fh, '<',
-		$self->{'book'}->dir() . '/' . $self->{'file'} . '.mdwn');
+		$self->{'book'}->dir() . '/' . $self->{'file'} . '.mdwn')
+		or croak('Cannot open "' . $self->{'file'} . '" source document');
 	$source_text = join('', <$source_fh>);
 	close($source_fh);
 
diff --git a/scripts/MarkdownBook/Document/HTML.pm b/scripts/MarkdownBook/Document/HTML.pm
index 9d61760..2852e8e 100644
--- a/scripts/MarkdownBook/Document/HTML.pm
+++ b/scripts/MarkdownBook/Document/HTML.pm
@@ -18,6 +18,7 @@ use warnings;
 
 use MarkdownBook::Document;
 use MarkdownBook::HTMLTree;
+use Carp;
 use Text::Markdown;
 use HTML::TreeBuilder;
 use HTML::Template;
@@ -143,7 +144,8 @@ sub _do_output_template
 
 	$doc_tmpl->param(BODY => $body);
 
-	open($doc_fh, '>', $self->file_path() . '.html');
+	open($doc_fh, '>', $self->file_path() . '.html')
+		or croak('Cannot open "' . $self->{'file'} . '" destination document');
 	$doc_tmpl->output(print_to => $doc_fh);
 	close($doc_fh);
 }
diff --git a/scripts/MarkdownBook/Document/Txt.pm b/scripts/MarkdownBook/Document/Txt.pm
index 6c7f038..cf65d92 100644
--- a/scripts/MarkdownBook/Document/Txt.pm
+++ b/scripts/MarkdownBook/Document/Txt.pm
@@ -17,6 +17,7 @@ use strict;
 use warnings;
 
 use MarkdownBook::Document;
+use Carp;
 
 package MarkdownBook::Document::Txt;
 
@@ -28,7 +29,8 @@ sub output
 	my $out_fh;
 
 	open($out_fh, '>',
-		$self->{'book'}->dir() . '/' . $self->{'file'} . '.txt');
+		$self->{'book'}->dir() . '/' . $self->{'file'} . '.txt')
+		or croak('Cannot open "' . $self->{'file'} . '" destination document');
 
 	# Print document title.
 	print($out_fh $self->{'title'} . "\n" .