4 files changed, 140 insertions, 1 deletions
diff --git a/libdevcore/CommonData.h b/libdevcore/CommonData.h
index ab4bfe68..6f40d7be 100644
--- a/libdevcore/CommonData.h
+++ b/libdevcore/CommonData.h
@@ -145,6 +145,13 @@ inline std::string toHex(u256 val, HexPrefix prefix = HexPrefix::DontAdd)
 	return (prefix == HexPrefix::Add) ? "0x" + str : str;
 }
 
+inline std::string toCompactHexWithPrefix(u256 val)
+{
+	std::ostringstream ret;
+	ret << std::hex << val;
+	return "0x" + ret.str();
+}
+
 // Algorithms for string and string-like collections.
 
 /// Escapes a string into the C-string representation.
diff --git a/libdevcore/IndentedWriter.cpp b/libdevcore/IndentedWriter.cpp
new file mode 100644
index 00000000..96aaf0fa
--- /dev/null
+++ b/libdevcore/IndentedWriter.cpp
@@ -0,0 +1,65 @@
+/*
+	This file is part of solidity.
+
+	solidity is free software: you can redistribute it and/or modify
+	it under the terms of the GNU General Public License as published by
+	the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+
+	solidity is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with solidity.  If not, see <http://www.gnu.org/licenses/>.
+*/
+/**
+ * @date 2017
+ * Indented text writer.
+ */
+
+#include <libdevcore/IndentedWriter.h>
+#include <libdevcore/Assertions.h>
+
+using namespace std;
+using namespace dev;
+
+string IndentedWriter::format() const
+{
+	string result;
+	for (auto const& line: m_lines)
+		result += string(line.indentation * 4, ' ') + line.contents + "\n";
+	return result;
+}
+
+void IndentedWriter::newLine()
+{
+	if (!m_lines.back().contents.empty())
+		m_lines.push_back({ string(), m_lines.back().indentation });
+}
+
+void IndentedWriter::indent()
+{
+	newLine();
+	m_lines.back().indentation++;
+}
+
+void IndentedWriter::unindent()
+{
+	newLine();
+	assertThrow(m_lines.back().indentation > 0, IndentedWriterError, "Negative indentation.");
+	m_lines.back().indentation--;
+}
+
+void IndentedWriter::add(string const& _str)
+{
+	m_lines.back().contents += _str;
+}
+
+void IndentedWriter::addLine(string const& _line)
+{
+	newLine();
+	add(_line);
+	newLine();
+}
diff --git a/libdevcore/IndentedWriter.h b/libdevcore/IndentedWriter.h
new file mode 100644
index 00000000..4ddd87ed
--- /dev/null
+++ b/libdevcore/IndentedWriter.h
@@ -0,0 +1,67 @@
+/*
+	This file is part of solidity.
+
+	solidity is free software: you can redistribute it and/or modify
+	it under the terms of the GNU General Public License as published by
+	the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+
+	solidity is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with solidity.  If not, see <http://www.gnu.org/licenses/>.
+*/
+/**
+ * @date 2017
+ * Indented text writer.
+ */
+
+#pragma once
+
+#include <vector>
+#include <string>
+
+#include <libdevcore/Exceptions.h>
+
+namespace dev
+{
+
+DEV_SIMPLE_EXCEPTION(IndentedWriterError);
+
+class IndentedWriter
+{
+public:
+	explicit IndentedWriter(): m_lines(std::vector<Line>{{std::string(), 0}}) {}
+
+	// Returns the formatted output.
+	std::string format() const;
+
+	// Go one indentation level in.
+	void indent();
+
+	// Go one indentation level out.
+	void unindent();
+
+	// Add text.
+	void add(std::string const& _str);
+
+	// Add text with new line.
+	void addLine(std::string const& _line);
+
+	// Add new line.
+	void newLine();
+
+private:
+	struct Line
+	{
+		std::string contents;
+		unsigned indentation;
+	};
+
+	std::vector<Line> m_lines;
+};
+
+}
diff --git a/libdevcore/Whiskers.cpp b/libdevcore/Whiskers.cpp
index 4bad8476..b0a4c755 100644
--- a/libdevcore/Whiskers.cpp
+++ b/libdevcore/Whiskers.cpp
@@ -90,7 +90,7 @@ string Whiskers::replace(
 		string tagName(_match[1]);
 		if (!tagName.empty())
 		{
-			assertThrow(_parameters.count(tagName), WhiskersError, "Tag " + tagName + " not found.");
+			assertThrow(_parameters.count(tagName), WhiskersError, "Value for tag " + tagName + " not provided.");
 			return _parameters.at(tagName);
 		}
 		else