tasks a-s

Task/S-Expressions/Perl/s-expressions-1.pl

@@ -0,0 +1,34 @@
+use Text::Balanced qw(extract_delimited extract_bracketed);
+
+sub sexpr
+{
+	my $txt = $_[0];
+	$txt =~ s/^\s+//s;
+	$txt =~ s/\s+$//s;
+	$txt =~ /^\((.*)\)$/s or die "Not an s-expression: <<<$txt>>>";
+	$txt = $1;
+
+	my $ret = [];
+	my $w;
+	while ($txt ne '') {
+		my $c = substr $txt,0,1;
+		if ($c eq '(') {
+			($w, $txt) = extract_bracketed($txt, '()');
+			$w = sexpr($w);
+		} elsif ($c eq '"') {
+			($w, $txt) = extract_delimited($txt, '"');
+			$w =~ s/^"(.*)"/$1/;
+		} else {
+			$txt =~ s/^(\S+)// and $w = $1;
+		}
+		push @$ret, $w;
+		$txt =~ s/^\s+//s;
+	}
+	return $ret;
+}
+
+sub quote
+{ (local $_ = $_[0]) =~ /[\s\"\(\)]/s ? do{s/\"/\\\"/gs; qq{"$_"}} : $_; }
+
+sub sexpr2txt
+{ qq{(@{[ map { ref($_) eq '' ? quote($_) : sexpr2txt($_) } @{$_[0]} ]})} }

Task/S-Expressions/Perl/s-expressions-2.pl

@@ -0,0 +1,13 @@
+my $s = sexpr(q{
+
+((data "quoted data" 123 4.5)
+ (data (!@# (4.5) "(more" "data)")))
+
+});
+
+# Dump structure
+use Data::Dumper;
+print Dumper $s;
+
+# Convert back
+print sexpr2txt($s)."\n";