Introduce view (and keep constant as an alias)

8 files changed, 13 insertions, 9 deletions

diff --git a/Changelog.md b/Changelog.md
index 39cbd44b..efcea03f 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -3,6 +3,7 @@
 Features:
  * ABI JSON: Include new field ``statemutability`` with values ``view``, ``nonpayable`` and ``payable``.
  * Parser: Display previous visibility specifier in error if multiple are found.
+ * Parser: Introduce ``view`` keyword on functions (``constant`` remains an alias for ``view``).
  * Syntax Checker: Support ``pragma experimental <feature>;`` to turn on experimental features.
  * Static Analyzer: Warn about large storage structures.
  * Metadata: Store experimental flag in metadata CBOR.
diff --git a/docs/types.rst b/docs/types.rst
index 13c848c2..9c1c73c6 100644
--- a/docs/types.rst
+++ b/docs/types.rst
@@ -337,7 +337,7 @@ be passed via and returned from external function calls.
 
 Function types are notated as follows::
 
-    function (<parameter types>) {internal|external} [constant|payable] [returns (<return types>)]
+    function (<parameter types>) {internal|external} [constant|view|payable] [returns (<return types>)]
 
 In contrast to the parameter types, the return types cannot be empty - if the
 function type should not return anything, the whole ``returns (<return types>)``
diff --git a/libsolidity/ast/ASTJsonConverter.cpp b/libsolidity/ast/ASTJsonConverter.cpp
index f7661357..cb74ea39 100644
--- a/libsolidity/ast/ASTJsonConverter.cpp
+++ b/libsolidity/ast/ASTJsonConverter.cpp
@@ -323,6 +323,7 @@ bool ASTJsonConverter::visit(FunctionDefinition const& _node)
 {
 	std::vector<pair<string, Json::Value>> attributes = {
 		make_pair("name", _node.name()),
+		// FIXME: remove with next breaking release
 		make_pair(m_legacy ? "constant" : "isDeclaredConst", _node.stateMutability() == StateMutability::View),
 		make_pair("payable", _node.isPayable()),
 		make_pair("statemutability", stateMutabilityToString(_node.stateMutability())),
@@ -415,6 +416,7 @@ bool ASTJsonConverter::visit(FunctionTypeName const& _node)
 		make_pair("payable", _node.isPayable()),
 		make_pair("visibility", Declaration::visibilityToString(_node.visibility())),
 		make_pair("statemutability", stateMutabilityToString(_node.stateMutability())),
+		// FIXME: remove with next breaking release
 		make_pair(m_legacy ? "constant" : "isDeclaredConst", _node.stateMutability() == StateMutability::View),
 		make_pair("parameterTypes", toJson(*_node.parameterTypeList())),
 		make_pair("returnParameterTypes", toJson(*_node.returnParameterTypeList())),
diff --git a/libsolidity/ast/Types.h b/libsolidity/ast/Types.h
index 56546a82..ce2d3bf8 100644
--- a/libsolidity/ast/Types.h
+++ b/libsolidity/ast/Types.h
@@ -993,7 +993,6 @@ public:
 		return *m_declaration;
 	}
 	bool hasDeclaration() const { return !!m_declaration; }
-	bool isConstant() const { return m_stateMutability == StateMutability::View; }
 	/// @returns true if the the result of this function only depends on its arguments
 	/// and it does not modify the state.
 	/// Currently, this will only return true for internal functions like keccak and ecrecover.
diff --git a/libsolidity/interface/ABI.cpp b/libsolidity/interface/ABI.cpp
index a7224e86..6e8563f7 100644
--- a/libsolidity/interface/ABI.cpp
+++ b/libsolidity/interface/ABI.cpp
@@ -35,7 +35,8 @@ Json::Value ABI::generate(ContractDefinition const& _contractDef)
 		Json::Value method;
 		method["type"] = "function";
 		method["name"] = it.second->declaration().name();
-		method["constant"] = it.second->isConstant();
+		// TODO: deprecate constant in a future release
+		method["constant"] = it.second->stateMutability() == StateMutability::View;
 		method["payable"] = it.second->isPayable();
 		method["statemutability"] = stateMutabilityToString(it.second->stateMutability());
 		method["inputs"] = formatTypeList(
diff --git a/libsolidity/parsing/Parser.cpp b/libsolidity/parsing/Parser.cpp
index 7455cbca..92a614e0 100644
--- a/libsolidity/parsing/Parser.cpp
+++ b/libsolidity/parsing/Parser.cpp
@@ -337,7 +337,8 @@ StateMutability Parser::parseStateMutability(Token::Value _token)
 	StateMutability stateMutability(StateMutability::NonPayable);
 	if (_token == Token::Payable)
 		stateMutability = StateMutability::Payable;
-	else if (_token == Token::Constant)
+	// FIXME: constant should be removed at the next breaking release
+	else if (_token == Token::View || _token == Token::Constant)
 		stateMutability = StateMutability::View;
 	else
 		solAssert(false, "Invalid state mutability specifier.");
diff --git a/libsolidity/parsing/Token.h b/libsolidity/parsing/Token.h
index efbe5e9e..3bc52f1d 100644
--- a/libsolidity/parsing/Token.h
+++ b/libsolidity/parsing/Token.h
@@ -176,6 +176,7 @@ namespace solidity
 	K(Throw, "throw", 0)                                               \
 	K(Using, "using", 0)                                               \
 	K(Var, "var", 0)                                                   \
+	K(View, "view", 0)                                                 \
 	K(While, "while", 0)                                               \
 	\
 	/* Ether subdenominations */                                       \
@@ -236,7 +237,6 @@ namespace solidity
 	K(Try, "try", 0)                                                   \
 	K(Type, "type", 0)                                                 \
 	K(TypeOf, "typeof", 0)                                             \
-	K(View, "view", 0)                                                 \
 	/* Illegal token - not able to scan. */                            \
 	T(Illegal, "ILLEGAL", 0)                                           \
 	\
@@ -290,7 +290,7 @@ public:
 	static bool isVisibilitySpecifier(Value op) { return isVariableVisibilitySpecifier(op) || op == External; }
 	static bool isVariableVisibilitySpecifier(Value op) { return op == Public || op == Private || op == Internal; }
 	static bool isLocationSpecifier(Value op) { return op == Memory || op == Storage; }
-	static bool isStateMutabilitySpecifier(Value op) { return op == Constant || op == Payable; }
+	static bool isStateMutabilitySpecifier(Value op) { return op == Constant || op == View || op == Payable; }
 	static bool isEtherSubdenomination(Value op) { return op == SubWei || op == SubSzabo || op == SubFinney || op == SubEther; }
 	static bool isTimeSubdenomination(Value op) { return op == SubSecond || op == SubMinute || op == SubHour || op == SubDay || op == SubWeek || op == SubYear; }
 	static bool isReservedKeyword(Value op) { return (Abstract <= op && op <= TypeOf); }
diff --git a/test/libsolidity/SolidityNameAndTypeResolution.cpp b/test/libsolidity/SolidityNameAndTypeResolution.cpp
index f5f607ca..380978e8 100644
--- a/test/libsolidity/SolidityNameAndTypeResolution.cpp
+++ b/test/libsolidity/SolidityNameAndTypeResolution.cpp
@@ -1172,7 +1172,7 @@ BOOST_AUTO_TEST_CASE(state_variable_accessors)
 	BOOST_REQUIRE(function && function->hasDeclaration());
 	auto returnParams = function->returnParameterTypes();
 	BOOST_CHECK_EQUAL(returnParams.at(0)->canonicalName(false), "uint256");
-	BOOST_CHECK(function->isConstant());
+	BOOST_CHECK(function->stateMutability() == StateMutability::View);
 
 	function = retrieveFunctionBySignature(*contract, "map(uint256)");
 	BOOST_REQUIRE(function && function->hasDeclaration());
@@ -1180,7 +1180,7 @@ BOOST_AUTO_TEST_CASE(state_variable_accessors)
 	BOOST_CHECK_EQUAL(params.at(0)->canonicalName(false), "uint256");
 	returnParams = function->returnParameterTypes();
 	BOOST_CHECK_EQUAL(returnParams.at(0)->canonicalName(false), "bytes4");
-	BOOST_CHECK(function->isConstant());
+	BOOST_CHECK(function->stateMutability() == StateMutability::View);
 
 	function = retrieveFunctionBySignature(*contract, "multiple_map(uint256,uint256)");
 	BOOST_REQUIRE(function && function->hasDeclaration());
@@ -1189,7 +1189,7 @@ BOOST_AUTO_TEST_CASE(state_variable_accessors)
 	BOOST_CHECK_EQUAL(params.at(1)->canonicalName(false), "uint256");
 	returnParams = function->returnParameterTypes();
 	BOOST_CHECK_EQUAL(returnParams.at(0)->canonicalName(false), "bytes4");
-	BOOST_CHECK(function->isConstant());
+	BOOST_CHECK(function->stateMutability() == StateMutability::View);
 }
 
 BOOST_AUTO_TEST_CASE(function_clash_with_state_variable_accessor)