DSL: allow function()use(this){} and function()use(this=x){}

doc/17-language-reference.md

@@ -1049,6 +1049,14 @@ function MakeHelloFunction(name) {
 }
 ```
 
+The `use` keyword also supports `this`, i.e.:
+
+```
+(function() use (this = [ "foo", "bar" ]) {
+  log(this)
+})()
+```
+
 ## Conditional Statements <a id="conditional-statements"></a>
 
 ### Conditional Statements: if/else <a id="conditional-statements-if-else"></a>

lib/base/function.cpp

@@ -10,8 +10,9 @@ using namespace icinga;
 REGISTER_TYPE_WITH_PROTOTYPE(Function, Function::GetPrototype());
 
 Function::Function(const String& name, Callback function, const std::vector<String>& args,
+	bool hasClosedThis, Value closedThis,
 	bool side_effect_free, bool deprecated)
-	: m_Callback(std::move(function))
+	: m_Callback(std::move(function)), m_HasClosedThis(hasClosedThis), m_ClosedThis(std::move(closedThis))
 {
 	SetName(name, true);
 	SetSideEffectFree(side_effect_free, true);
@@ -21,6 +22,10 @@ Function::Function(const String& name, Callback function, const std::vector<Stri
 
 Value Function::Invoke(const std::vector<Value>& arguments)
 {
+	if (m_HasClosedThis) {
+		return InvokeThis(m_ClosedThis, arguments);
+	}
+
 	ScriptFrame frame(false);
 	return m_Callback(arguments);
 }

lib/base/function.hpp

@@ -27,8 +27,9 @@ public:
 
 	template<typename F>
 	Function(const String& name, F function, const std::vector<String>& args = std::vector<String>(),
+		bool hasClosedThis = false, Value closedThis = Value(),
 		bool side_effect_free = false, bool deprecated = false)
-		: Function(name, WrapFunction(function), args, side_effect_free, deprecated)
+		: Function(name, WrapFunction(function), args, hasClosedThis, std::move(closedThis), side_effect_free, deprecated)
 	{ }
 
 	Value Invoke(const std::vector<Value>& arguments = std::vector<Value>());
@@ -50,8 +51,11 @@ public:
 
 private:
 	Callback m_Callback;
+	bool m_HasClosedThis;
+	Value m_ClosedThis;
 
 	Function(const String& name, Callback function, const std::vector<String>& args,
+		bool hasClosedThis, Value closedThis,
 		bool side_effect_free, bool deprecated);
 };
 

lib/config/config_parser.yy

@@ -1103,6 +1103,14 @@ use_specifier_item: identifier
 		$$ = new std::pair<String, std::unique_ptr<Expression> >(std::move(*$1), std::unique_ptr<Expression>($3));
 		delete $1;
 	}
+	| T_THIS
+	{
+		$$ = new std::pair<String, std::unique_ptr<Expression> >("this", std::unique_ptr<Expression>(new GetScopeExpression(ScopeThis)));
+	}
+	| T_THIS T_SET rterm
+	{
+		$$ = new std::pair<String, std::unique_ptr<Expression> >("this", std::unique_ptr<Expression>($3));
+	}
 	;
 
 apply_for_specifier: /* empty */

lib/config/expression.cpp

@@ -904,7 +904,7 @@ ExpressionResult ImportDefaultTemplatesExpression::DoEvaluate(ScriptFrame& frame
 
 ExpressionResult FunctionExpression::DoEvaluate(ScriptFrame& frame, DebugHint *dhint) const
 {
-	return VMOps::NewFunction(frame, m_Name, m_Args, m_ClosedVars, m_Expression);
+	return VMOps::NewFunction(frame, m_Name, m_Args, m_ClosedVars, m_ClosedThis, m_Expression);
 }
 
 ExpressionResult ApplyExpression::DoEvaluate(ScriptFrame& frame, DebugHint *dhint) const

lib/config/expression.hpp

@@ -814,7 +814,14 @@ public:
 	FunctionExpression(String name, std::vector<String> args,
 		std::map<String, std::unique_ptr<Expression> >&& closedVars, std::unique_ptr<Expression> expression, const DebugInfo& debugInfo = DebugInfo())
 		: DebuggableExpression(debugInfo), m_Name(std::move(name)), m_Args(std::move(args)), m_ClosedVars(std::move(closedVars)), m_Expression(expression.release())
-	{ }
+	{
+		auto closedThis (m_ClosedVars.find("this"));
+
+		if (closedThis != m_ClosedVars.end()) {
+			m_ClosedThis = std::move(closedThis->second);
+			m_ClosedVars.erase(closedThis);
+		}
+	}
 
 protected:
 	ExpressionResult DoEvaluate(ScriptFrame& frame, DebugHint *dhint) const override;
@@ -823,6 +830,7 @@ private:
 	String m_Name;
 	std::vector<String> m_Args;
 	std::map<String, std::unique_ptr<Expression> > m_ClosedVars;
+	std::unique_ptr<Expression> m_ClosedThis;
 	Expression::Ptr m_Expression;
 };
 

lib/config/vmops.hpp

@@ -91,9 +91,15 @@ public:
 	}
 
 	static inline Value NewFunction(ScriptFrame& frame, const String& name, const std::vector<String>& argNames,
-		const std::map<String, std::unique_ptr<Expression> >& closedVars, const Expression::Ptr& expression)
+		const std::map<String, std::unique_ptr<Expression> >& closedVars,
+		const std::unique_ptr<Expression>& closedThis, const Expression::Ptr& expression)
 	{
 		auto evaluatedClosedVars = EvaluateClosedVars(frame, closedVars);
+		Value evaluatedClosedThis;
+
+		if (closedThis) {
+			evaluatedClosedThis = closedThis->Evaluate(frame);
+		}
 
 		auto wrapper = [argNames, evaluatedClosedVars, expression](const std::vector<Value>& arguments) -> Value {
 			if (arguments.size() < argNames.size())
@@ -112,7 +118,7 @@ public:
 			return expression->Evaluate(*frame);
 		};
 
-		return new Function(name, wrapper, argNames);
+		return new Function(name, wrapper, argNames, (bool)closedThis, std::move(evaluatedClosedThis));
 	}
 
 	static inline Value NewApply(ScriptFrame& frame, const String& type, const String& target, const String& name, const Expression::Ptr& filter,