initial checkin of SkSL compiler
BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1984363002
CQ_EXTRA_TRYBOTS=client.skia.compile:Build-Ubuntu-GCC-x86_64-Release-CMake-Trybot,Build-Mac-Clang-x86_64-Release-CMake-Trybot
Review-Url: https://codereview.chromium.org/1984363002
diff --git a/src/sksl/ast/SkSLASTExpression.h b/src/sksl/ast/SkSLASTExpression.h
new file mode 100644
index 0000000..8a48271
--- /dev/null
+++ b/src/sksl/ast/SkSLASTExpression.h
@@ -0,0 +1,41 @@
+/*
+ * 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_ASTEXPRESSION
+#define SKSL_ASTEXPRESSION
+
+#include "SkSLASTPositionNode.h"
+
+namespace SkSL {
+
+/**
+ * Abstract supertype of all expressions.
+ */
+struct ASTExpression : public ASTPositionNode {
+ enum Kind {
+ kFloat_Kind,
+ kIdentifier_Kind,
+ kInt_Kind,
+ kBool_Kind,
+ kPrefix_Kind,
+ kSuffix_Kind,
+ kBinary_Kind,
+ kTernary_Kind
+ };
+
+ ASTExpression(Position position, Kind kind)
+ : INHERITED(position)
+ , fKind(kind) {}
+
+ const Kind fKind;
+
+ typedef ASTPositionNode INHERITED;
+};
+
+} // namespace
+
+#endif