LLL: implement WITH keyword

2 files changed, 42 insertions, 0 deletions

diff --git a/liblll/CodeFragment.cpp b/liblll/CodeFragment.cpp
index c6ab86f5..b32f14e9 100644
--- a/liblll/CodeFragment.cpp
+++ b/liblll/CodeFragment.cpp
@@ -285,6 +285,35 @@ void CodeFragment::constructOperation(sp::utree const& _t, CompilerState& _s)
 			m_asm.append((u256)varAddress(firstAsString()));
 			m_asm.append(Instruction::MLOAD);
 		}
+		else if (us == "WITH")
+		{
+			if (_t.size() != 4)
+				error<IncorrectParameterCount>();
+			string key = firstAsString();
+			if (_s.vars.find(key) != _s.vars.end())
+				error<InvalidName>(string("Symbol already used: ") + key);
+
+			// Create variable
+			// TODO: move this to be a stack variable (and not a memory variable)
+			size_t c = 0;
+			for (auto const& i: _t)
+				if (c++ == 2)
+					m_asm.append(CodeFragment(i, _s, m_readFile, false).m_asm);
+			m_asm.append((u256)varAddress(key, true));
+			m_asm.append(Instruction::MSTORE);
+
+			// Insert sub with variable access, but new state
+			CompilerState ns = _s;
+			c = 0;
+			for (auto const& i: _t)
+				if (c++ == 3)
+					m_asm.append(CodeFragment(i, _s, m_readFile, false).m_asm);
+
+			// Remove variable
+			auto it = _s.vars.find(key);
+			if (it != _s.vars.end())
+				_s.vars.erase(it);
+		}
 		else if (us == "REF")
 			m_asm.append((u256)varAddress(firstAsString()));
 		else if (us == "DEF")
diff --git a/test/liblll/EndToEndTest.cpp b/test/liblll/EndToEndTest.cpp
index 60aef7b0..aad89b91 100644
--- a/test/liblll/EndToEndTest.cpp
+++ b/test/liblll/EndToEndTest.cpp
@@ -109,6 +109,19 @@ BOOST_AUTO_TEST_CASE(variables)
 	BOOST_CHECK(callFallback() == encodeArgs(u256(488)));
 }
 
+BOOST_AUTO_TEST_CASE(with)
+{
+	char const* sourceCode = R"(
+		(returnlll
+			(seq
+				(set 'x 11)
+				(with 'y 22 { [0]:(+ (get 'x) (get 'y)) })
+				(return 0 32)))
+	)";
+	compileAndRun(sourceCode);
+	BOOST_CHECK(callFallback() == toBigEndian(u256(33)));
+}
+
 BOOST_AUTO_TEST_CASE(when)
 {
 	char const* sourceCode = R"(