initial checkin of SkSL compiler

src/sksl/ir/SkSLVarDeclaration.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_VARDECLARATION
+#define SKSL_VARDECLARATION
+
+#include "SkSLExpression.h"
+#include "SkSLStatement.h"
+#include "SkSLVariable.h"
+
+namespace SkSL {
+
+/**
+ * A variable declaration, which may consist of multiple individual variables. For instance

[dogben, 2016/06/22 17:43:58]

Is there any reason not to split the multiple variable case into separate
individual VarDeclaration objects for IR? Seems like that would make things
simpler.

[ethannicholas, 2016/06/24 21:23:10]

I had started to do it that way, but then a single variable declaration would
turn into multiple statements, which complicated handling in various other
spots. Ultimately this seemed less painful to me.

+ * 'int x, y = 1, z[4][2];' is a single VarDeclaration. This declaration would have a type of 'int', 
+ * names ['x', 'y', 'z'], sizes of [[], [], [4, 2]], and values of [null, 1, null].
+ */
+struct VarDeclaration : public ProgramElement {
+    VarDeclaration(Position position, std::vector<std::shared_ptr<Variable>> vars,
+                   std::vector<std::vector<std::unique_ptr<Expression>>> sizes,
+                   std::vector<std::unique_ptr<Expression>> values)
+    : INHERITED(position, kVar_Kind) 
+    , fVars(std::move(vars))
+    , fSizes(std::move(sizes))
+    , fValues(std::move(values)) {}
+
+    std::string description() const override {
+        std::string result = fVars[0]->fModifiers.description();
+        std::shared_ptr<Type> baseType = fVars[0]->fType;
+        while (baseType->kind() == Type::kArray_Kind) {
+            baseType = baseType->componentType();
+        }
+        result += baseType->description();
+        std::string separator = " ";
+        for (size_t i = 0; i < fVars.size(); i++) {
+            result += separator;
+            separator = ", ";
+            result += fVars[i]->fName;
+            for (size_t j = 0; j < fSizes[i].size(); j++) {
+                if (fSizes[i][j]) {
+                    result += "[" + fSizes[i][j]->description() + "]";
+                } else {
+                    result += "[]";
+                }
+            }
+            if (fValues[i]) {
+                result += " = " + fValues[i]->description();
+            }
+        }
+        result += ";";
+        return result;
+    }
+
+    const std::vector<std::shared_ptr<Variable>> fVars;
+    const std::vector<std::vector<std::unique_ptr<Expression>>> fSizes;
+    const std::vector<std::unique_ptr<Expression>> fValues;
+
+    typedef ProgramElement INHERITED;
+};
+
+} // namespace
+
+#endif