initial checkin of SkSL compiler

src/sksl/ir/SkSLFunctionDeclaration.h

+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+ 
+#ifndef SKSL_FUNCTIONDECLARATION
+#define SKSL_FUNCTIONDECLARATION
+
+#include "SkSLModifiers.h"
+#include "SkSLSymbol.h"
+#include "SkSLType.h"
+#include "SkSLVariable.h"
+
+namespace SkSL {
+
+/**
+ * A function declaration (not a definition -- does not contain a body).
+ */
+struct FunctionDeclaration : public Symbol {
+    FunctionDeclaration(Position position, std::string name, 
+                        std::vector<std::shared_ptr<Variable>> parameters, 
+                        std::shared_ptr<Type> returnType)
+    : INHERITED(position, kFunctionDeclaration_Kind, std::move(name))
+    , fDefined(false)
+    , fParameters(parameters)
+    , fReturnType(returnType) {}
+
+    std::string description() const override {
+        std::string result = fReturnType->description() + " " + fName + "(";
+        std::string separator = "";
+        for (auto p : fParameters) {
+            result += separator;
+            separator = ", ";
+            result += p->description();
+        }
+        result += ")";
+        return result;
+    }
+
+    bool matches(FunctionDeclaration& f) {
+        return fName == f.fName && fParameters == f.fParameters;
+    }
+
+    mutable bool fDefined;
+    const std::vector<std::shared_ptr<Variable>> fParameters;
+    const std::shared_ptr<Type> fReturnType;
+
+    typedef Symbol INHERITED;
+};
+
+} // namespace
+
+#endif