Update from Google.
--
MOE_MIGRATED_REVID=85702957
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/Argument.java b/src/main/java/com/google/devtools/build/lib/syntax/Argument.java
new file mode 100644
index 0000000..0706dee
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/syntax/Argument.java
@@ -0,0 +1,122 @@
+// Copyright 2014 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+package com.google.devtools.build.lib.syntax;
+
+/**
+ * Syntax node for a function argument. This can be a key/value pair such as
+ * appears as a keyword argument to a function call or just an expression that
+ * is used as a positional argument. It also can be used for function definitions
+ * to identify the name (and optionally the default value) of the argument.
+ */
+public final class Argument extends ASTNode {
+
+ private final Ident name;
+
+ private final Expression value;
+
+ private final boolean kwargs;
+
+ /**
+ * Create a new argument.
+ * At call site: name is optional, value is mandatory. kwargs is true for ** arguments.
+ * At definition site: name is mandatory, (default) value is optional.
+ */
+ public Argument(Ident name, Expression value, boolean kwargs) {
+ this.name = name;
+ this.value = value;
+ this.kwargs = kwargs;
+ }
+
+ public Argument(Ident name, Expression value) {
+ this.name = name;
+ this.value = value;
+ this.kwargs = false;
+ }
+
+ /**
+ * Creates an Argument with null as name. It can be used as positional arguments
+ * of function calls.
+ */
+ public Argument(Expression value) {
+ this(null, value);
+ }
+
+ /**
+ * Creates an Argument with null as value. It can be used as a mandatory keyword argument
+ * of a function definition.
+ */
+ public Argument(Ident name) {
+ this(name, null);
+ }
+
+ /**
+ * Returns the name of this keyword argument or null if this argument is
+ * positional.
+ */
+ public Ident getName() {
+ return name;
+ }
+
+ /**
+ * Returns the String value of the Ident of this argument. Shortcut for arg.getName().getName().
+ */
+ public String getArgName() {
+ return name.getName();
+ }
+
+ /**
+ * Returns the syntax of this argument expression.
+ */
+ public Expression getValue() {
+ return value;
+ }
+
+ /**
+ * Returns true if this argument is positional.
+ */
+ public boolean isPositional() {
+ return name == null && !kwargs;
+ }
+
+ /**
+ * Returns true if this argument is a keyword argument.
+ */
+ public boolean isNamed() {
+ return name != null;
+ }
+
+ /**
+ * Returns true if this argument is a **kwargs argument.
+ */
+ public boolean isKwargs() {
+ return kwargs;
+ }
+
+ /**
+ * Returns true if this argument has value.
+ */
+ public boolean hasValue() {
+ return value != null;
+ }
+
+ @Override
+ public String toString() {
+ return isNamed() ? name + "=" + value : String.valueOf(value);
+ }
+
+ @Override
+ public void accept(SyntaxTreeVisitor visitor) {
+ visitor.visit(this);
+ }
+}
