1 files changed, 107 insertions, 0 deletions
diff --git a/ListParser.pm b/ListParser.pm
new file mode 100644
index 0000000..9e3e511
--- /dev/null
+++ b/ListParser.pm
@@ -0,0 +1,107 @@
+package ListParser;
+
+sub parse_mapping {
+	my ($input) = @_;
+	my $key, $value;
+	my $i = 0;
+	my $string_start, $string_end;
+	$string_start = $string_end = undef;
+
+	# Are we currently lexing inside a string literal?
+	my $is_string = 0;
+
+	# Currently parsing key or value?
+	my $is_key = 1;
+
+	while ($i < length($input)) {
+		my $c = substr($input, $i, 1);
+		my $lookahead = substr($input, $i+1, 1);
+
+		if ($is_string and $c eq "'") {
+			$is_string = 0;
+			$string_end = $i;
+			if (not $is_key) {
+				$value = substr($input, $string_start, $string_end - $string_start);
+			}
+			$i++;
+			next;
+		}
+		if (not $is_string) {
+			if ($c =~ /\s/) {
+				# allow whitespace
+			} elsif ($c eq "'") {
+				return ("Key/value must consist of single string", undef, undef) if defined $string_end;
+				$is_string = 1;
+				$string_start = $i + 1;
+			} elsif ($c eq "=") {
+				return ("Expected > after =, got $lookahead", undef, undef) unless $lookahead eq ">";
+				return ("Unexpected '=>'.", undef, undef) unless $is_key;
+				$i++;
+
+				$key = substr($input, $string_start, $string_end - $string_start);
+				$string_start = $string_end = undef;
+				$is_key = 0;
+			} else {
+				return ("Unexpected $c", undef, undef);
+			}
+		}
+		$i++;
+	}
+
+	return (undef, $key, $value);
+}
+
+sub parse_list {
+	my ($input, $is_hash) = @_;
+	my $c_start = $is_hash ? "{" : "[";
+	my $c_end   = $is_hash ? "}" : "]";
+	my %h_res;
+	my @a_res;
+	my $i = 0;
+
+	# Index of the start of the current item
+	my $item_i = 0;
+
+	# Level of nested lists, 1 being the minimum
+	my $nest = 1;
+
+	return ("Error: expected $c_start", undef) unless substr($input, $i, 1) eq $c_start;
+
+	$i++;
+	$item_i = $i;
+
+	while ($nest != 0 && $i < length($input)) {
+		my $c = substr($input, $i, 1);
+
+		if ($c eq $c_start) {
+			$nest++;
+		} elsif ($c eq $c_end) {
+			$nest--;
+		}
+
+		if (($nest == 1 and $c eq ",") || ($nest == 0 and $c eq $c_end)) {
+			my $item = substr($input, $item_i, $i - $item_i);
+			$item =~ s/^\s+|\s+$//g;
+			if ($is_hash) {
+				# FIXME should we die on duplicate keys or no?
+				my ($error, $key, $value) = parse_mapping($item);
+				die $error if $error;
+				$h_res{$key} = $value;
+			} else {
+				push @a_res, $item;
+			}
+			$item_i = $i+1;
+		}
+		$i++;
+	}
+
+	return ("Error: expected $c_end, got end of line", undef) unless $nest == 0;
+
+	if ($i != length($input)) {
+		return ("Error: unexpected item in the bagging area (after '$c_end')", undef);
+	}
+
+	return (undef, %h_res) if $is_hash;
+	return (undef, @a_res);
+}
+1;