Merge pull request #2426 from ethereum/miniMoustache

Whiskers template system

7 files changed, 364 insertions, 0 deletions

diff --git a/Changelog.md b/Changelog.md
index 4bf85d5f..fdba5a46 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -10,6 +10,7 @@ Features:
  * Inline Assembly: introduce ``keccak256`` as an opcode. ``sha3`` is still a valid alias.
  * Inline Assembly: ``for`` and ``switch`` statements.
  * Inline Assembly: function definitions and function calls.
+ * Code Generator: Added the Whiskers template system.
 
 Bugfixes:
  * Type Checker: Make UTF8-validation a bit more sloppy to include more valid sequences.
diff --git a/cmake/UseDev.cmake b/cmake/UseDev.cmake
index 4461a8a0..68df691a 100644
--- a/cmake/UseDev.cmake
+++ b/cmake/UseDev.cmake
@@ -10,6 +10,7 @@ function(eth_apply TARGET REQUIRED SUBMODULE)
 		target_link_libraries(${TARGET} ${Boost_RANDOM_LIBRARIES})
 		target_link_libraries(${TARGET} ${Boost_FILESYSTEM_LIBRARIES})
 		target_link_libraries(${TARGET} ${Boost_SYSTEM_LIBRARIES})
+		target_link_libraries(${TARGET} ${Boost_REGEX_LIBRARIES})
 
 		if (DEFINED MSVC)
 			target_link_libraries(${TARGET} ${Boost_CHRONO_LIBRARIES})
diff --git a/docs/assembly.rst b/docs/assembly.rst
index 7ef41483..83643634 100644
--- a/docs/assembly.rst
+++ b/docs/assembly.rst
@@ -13,6 +13,8 @@ TODO: Write about how scoping rules of inline assembly are a bit different
 and the complications that arise when for example using internal functions
 of libraries. Furthermore, write about the symbols defined by the compiler.
 
+.. _inline-assembly:
+
 Inline Assembly
 ===============
 
diff --git a/docs/contributing.rst b/docs/contributing.rst
index 1f869dbb..559f9f6a 100644
--- a/docs/contributing.rst
+++ b/docs/contributing.rst
@@ -74,3 +74,22 @@ To run a subset of tests, filters can be used:
 ``soltest -t TestSuite/TestName -- --ipcpath /tmp/testeth/geth.ipc``, where ``TestName`` can be a wildcard ``*``.
 
 Alternatively, there is a testing script at ``scripts/test.sh`` which executes all tests.
+
+Whiskers
+========
+
+*Whiskers* is a templating system similar to `Moustache <https://mustache.github.io>`_. It is used by the
+compiler in various places to aid readability, and thus maintainability and verifiability, of the code.
+
+The syntax comes with a substantial difference to Moustache: the template markers ``{{`` and ``}}`` are
+replaced by ``<`` and ``>`` in order to aid parsing and avoid conflicts with :ref:`inline-assembly`
+(The symbols ``<`` and ``>`` are invalid in inline assembly, while ``{`` and ``}`` are used to delimit blocks).
+Another limitation is that lists are only resolved one depth and they will not recurse. This may change in the future.
+
+A rough specification is the following:
+
+Any occurrence of ``<name>`` is replaced by the string-value of the supplied variable ``name`` without any
+escaping and without iterated replacements. An area can be delimited by ``<#name>...</name>``. It is replaced
+by as many concatenations of its contents as there were sets of variables supplied to the template system,
+each time replacing any ``<inner>`` items by their respective value. Top-level variales can also be used
+inside such areas.
\ No newline at end of file
diff --git a/libdevcore/Whiskers.cpp b/libdevcore/Whiskers.cpp
new file mode 100644
index 00000000..4bad8476
--- /dev/null
+++ b/libdevcore/Whiskers.cpp
@@ -0,0 +1,127 @@
+/*
+	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/>.
+*/
+/** @file Whiskers.cpp
+ * @author Chris <chis@ethereum.org>
+ * @date 2017
+ *
+ * Moustache-like templates.
+ */
+
+#include <libdevcore/Whiskers.h>
+
+#include <libdevcore/Assertions.h>
+
+#include <boost/regex.hpp>
+
+using namespace std;
+using namespace dev;
+
+Whiskers::Whiskers(string const& _template):
+m_template(_template)
+{
+}
+
+Whiskers& Whiskers::operator ()(string const& _parameter, string const& _value)
+{
+	assertThrow(
+		m_parameters.count(_parameter) == 0,
+		WhiskersError,
+		_parameter + " already set."
+	);
+	assertThrow(
+		m_listParameters.count(_parameter) == 0,
+		WhiskersError,
+		_parameter + " already set as list parameter."
+	);
+	m_parameters[_parameter] = _value;
+
+	return *this;
+}
+
+Whiskers& Whiskers::operator ()(
+	string const& _listParameter,
+	vector<map<string, string>> const& _values
+)
+{
+	assertThrow(
+		m_listParameters.count(_listParameter) == 0,
+		WhiskersError,
+		_listParameter + " already set."
+	);
+	assertThrow(
+		m_parameters.count(_listParameter) == 0,
+		WhiskersError,
+		_listParameter + " already set as value parameter."
+	);
+	m_listParameters[_listParameter] = _values;
+
+	return *this;
+}
+
+string Whiskers::render() const
+{
+	return replace(m_template, m_parameters, m_listParameters);
+}
+
+string Whiskers::replace(
+	string const& _template,
+	StringMap const& _parameters,
+	map<string, vector<StringMap>> const& _listParameters
+)
+{
+	using namespace boost;
+	static regex listOrTag("<([^#/>]+)>|<#([^>]+)>(.*?)</\\2>");
+	return regex_replace(_template, listOrTag, [&](match_results<string::const_iterator> _match) -> string
+	{
+		string tagName(_match[1]);
+		if (!tagName.empty())
+		{
+			assertThrow(_parameters.count(tagName), WhiskersError, "Tag " + tagName + " not found.");
+			return _parameters.at(tagName);
+		}
+		else
+		{
+			string listName(_match[2]);
+			string templ(_match[3]);
+			assertThrow(!listName.empty(), WhiskersError, "");
+			assertThrow(
+				_listParameters.count(listName),
+				WhiskersError, "List parameter " + listName + " not set."
+			);
+			string replacement;
+			for (auto const& parameters: _listParameters.at(listName))
+				replacement += replace(templ, joinMaps(_parameters, parameters));
+			return replacement;
+		}
+	});
+}
+
+Whiskers::StringMap Whiskers::joinMaps(
+	Whiskers::StringMap const& _a,
+	Whiskers::StringMap const& _b
+)
+{
+	Whiskers::StringMap ret = _a;
+	for (auto const& x: _b)
+		assertThrow(
+			ret.insert(x).second,
+			WhiskersError,
+			"Parameter collision"
+		);
+	return ret;
+}
+
diff --git a/libdevcore/Whiskers.h b/libdevcore/Whiskers.h
new file mode 100644
index 00000000..21d46af4
--- /dev/null
+++ b/libdevcore/Whiskers.h
@@ -0,0 +1,87 @@
+/*
+	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/>.
+*/
+/** @file Whiskers.h
+ * @author Chris <chis@ethereum.org>
+ * @date 2017
+ *
+ * Moustache-like templates.
+ */
+
+#pragma once
+
+#include <libdevcore/Exceptions.h>
+
+#include <string>
+#include <map>
+#include <vector>
+
+namespace dev
+{
+
+DEV_SIMPLE_EXCEPTION(WhiskersError);
+
+///
+/// Moustache-like templates.
+///
+/// Usage:
+///     std::vector<std::map<std::string, std::string>> listValues(2);
+///     listValues[0]["k"] = "key1";
+///     listValues[0]["v"] = "value1";
+///     listValues[1]["k"] = "key2";
+///     listValues[1]["v"] = "value2";
+///     auto s = Whiskers("<p1>\n<#list><k> -> <v>\n</list>")
+///         ("p1", "HEAD")
+///         ("list", listValues)
+///         .render();
+///
+/// results in s == "HEAD\nkey1 -> value1\nkey2 -> value2\n"
+///
+/// Note that lists cannot themselves contain lists - this would be a future feature.
+class Whiskers
+{
+public:
+	using StringMap = std::map<std::string, std::string>;
+	using StringListMap = std::map<std::string, std::vector<StringMap>>;
+
+	explicit Whiskers(std::string const& _template);
+
+	/// Sets a single parameter, <paramName>.
+	Whiskers& operator()(std::string const& _parameter, std::string const& _value);
+	/// Sets a list parameter, <#listName> </listName>.
+	Whiskers& operator()(
+		std::string const& _listParameter,
+		std::vector<StringMap> const& _values
+	);
+
+	std::string render() const;
+
+private:
+	static std::string replace(
+		std::string const& _template,
+		StringMap const& _parameters,
+		StringListMap const& _listParameters = StringListMap()
+	);
+
+	/// Joins the two maps throwing an exception if two keys are equal.
+	static StringMap joinMaps(StringMap const& _a, StringMap const& _b);
+
+	std::string m_template;
+	StringMap m_parameters;
+	StringListMap m_listParameters;
+};
+
+}
diff --git a/test/libdevcore/MiniMoustache.cpp b/test/libdevcore/MiniMoustache.cpp
new file mode 100644
index 00000000..84149173
--- /dev/null
+++ b/test/libdevcore/MiniMoustache.cpp
@@ -0,0 +1,127 @@
+/*
+	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/>.
+*/
+/**
+ * Unit tests for the mini moustache class.
+ */
+
+#include <libdevcore/Whiskers.h>
+
+#include "../TestHelper.h"
+
+using namespace std;
+
+namespace dev
+{
+namespace test
+{
+
+BOOST_AUTO_TEST_SUITE(WhiskersTest)
+
+BOOST_AUTO_TEST_CASE(no_templates)
+{
+	string templ = "this text does not contain templates";
+	BOOST_CHECK_EQUAL(Whiskers(templ).render(), templ);
+}
+
+BOOST_AUTO_TEST_CASE(basic_replacement)
+{
+	string templ = "a <b> x <c> -> <d>.";
+	string result = Whiskers(templ)
+		("b", "BE")
+		("c", "CE")
+		("d", "DE")
+		.render();
+	BOOST_CHECK_EQUAL(result, "a BE x CE -> DE.");
+}
+
+BOOST_AUTO_TEST_CASE(tag_unavailable)
+{
+	string templ = "<b>";
+	Whiskers m(templ);
+	BOOST_CHECK_THROW(m.render(), WhiskersError);
+}
+
+BOOST_AUTO_TEST_CASE(complicated_replacement)
+{
+	string templ = "a <b> x <complicated> \n <nes<ted>>.";
+	string result = Whiskers(templ)
+		("b", "BE")
+		("complicated", "CO<M>PL")
+		("nes<ted", "NEST")
+		.render();
+	BOOST_CHECK_EQUAL(result, "a BE x CO<M>PL \n NEST>.");
+}
+
+BOOST_AUTO_TEST_CASE(non_existing_list)
+{
+	string templ = "a <#b></b>";
+	Whiskers m(templ);
+	BOOST_CHECK_THROW(m.render(), WhiskersError);
+}
+
+BOOST_AUTO_TEST_CASE(empty_list)
+{
+	string templ = "a <#b></b>x";
+	string result = Whiskers(templ)("b", vector<Whiskers::StringMap>{}).render();
+	BOOST_CHECK_EQUAL(result, "a x");
+}
+
+BOOST_AUTO_TEST_CASE(list)
+{
+	string templ = "a<#b>( <g> - <h> )</b>x";
+	vector<map<string, string>> list(2);
+	list[0]["g"] = "GE";
+	list[0]["h"] = "H";
+	list[1]["g"] = "2GE";
+	list[1]["h"] = "2H";
+	string result = Whiskers(templ)("b", list).render();
+	BOOST_CHECK_EQUAL(result, "a( GE - H )( 2GE - 2H )x");
+}
+
+BOOST_AUTO_TEST_CASE(recursive_list)
+{
+	// Check that templates resulting from lists are not expanded again
+	string templ = "a<#b> 1<g>3 </b><x>";
+	vector<map<string, string>> list(1);
+	list[0]["g"] = "<x>";
+	string result = Whiskers(templ)("x", "X")("b", list).render();
+	BOOST_CHECK_EQUAL(result, "a 1<x>3 X");
+}
+
+BOOST_AUTO_TEST_CASE(list_can_access_upper)
+{
+	string templ = "<#b>(<a>)</b>";
+	vector<map<string, string>> list(2);
+	Whiskers m(templ);
+	string result = m("a", "A")("b", list).render();
+	BOOST_CHECK_EQUAL(result, "(A)(A)");
+}
+
+BOOST_AUTO_TEST_CASE(parameter_collision)
+{
+	string templ = "a <#b></b>";
+	vector<map<string, string>> list(1);
+	list[0]["a"] = "x";
+	Whiskers m(templ);
+	m("a", "X")("b", list);
+	BOOST_CHECK_THROW(m.render(), WhiskersError);
+}
+
+BOOST_AUTO_TEST_SUITE_END()
+
+}
+}