1 files changed, 66 insertions, 0 deletions
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/Ident.java b/src/main/java/com/google/devtools/build/lib/syntax/Ident.java
new file mode 100644
index 0000000000..86bd458ab7
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/syntax/Ident.java
@@ -0,0 +1,66 @@
+// 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 an identifier.
+ */
+public final class Ident extends Expression {
+
+  private final String name;
+
+  public Ident(String name) {
+    this.name = name;
+  }
+
+  /**
+   *  Returns the name of the Ident.
+   */
+  public String getName() {
+    return name;
+  }
+
+  @Override
+  public String toString() {
+    return name;
+  }
+
+  @Override
+  Object eval(Environment env) throws EvalException {
+    try {
+      return env.lookup(name);
+    } catch (Environment.NoSuchVariableException e) {
+      if (name.equals("$error$")) {
+        throw new EvalException(getLocation(), "contains syntax error(s)", true);
+      } else {
+        throw new EvalException(getLocation(), "name '" + name + "' is not defined");
+      }
+    }
+  }
+
+  @Override
+  public void accept(SyntaxTreeVisitor visitor) {
+    visitor.visit(this);
+  }
+
+  @Override
+  SkylarkType validate(ValidationEnvironment env) throws EvalException {
+    if (env.hasSymbolInEnvironment(name)) {
+      return env.getVartype(name);
+    } else {
+      throw new EvalException(getLocation(), "name '" + name + "' is not defined");
+    }
+  }
+}