1 files changed, 43 insertions, 0 deletions
diff --git a/src/main/java/com/google/escapevelocity/ConstantExpressionNode.java b/src/main/java/com/google/escapevelocity/ConstantExpressionNode.java
new file mode 100644
index 0000000..50fc9bc
--- /dev/null
+++ b/src/main/java/com/google/escapevelocity/ConstantExpressionNode.java
@@ -0,0 +1,43 @@
+/*
+ * Copyright (C) 2018 Google, Inc.
+ *
+ * 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.escapevelocity;
+
+/**
+ * A node in the parse tree representing a constant value. Evaluating the node yields the constant
+ * value. Instances of this class are used both in expressions, like the {@code 23} in
+ * {@code #set ($x = 23)}, and for literal text in templates. In the template...
+ * <pre>{@code
+ * abc#{if}($x == 5)def#{end}xyz
+ * }</pre>
+ * ...each of the strings {@code abc}, {@code def}, {@code xyz} is represented by an instance of
+ * this class that {@linkplain #evaluate evaluates} to that string, and the value {@code 5} is
+ * represented by an instance of this class that evaluates to the integer 5.
+ *
+ * @author emcmanus@google.com (Éamonn McManus)
+ */
+class ConstantExpressionNode extends ExpressionNode {
+  private final Object value;
+
+  ConstantExpressionNode(String resourceName, int lineNumber, Object value) {
+    super(resourceName, lineNumber);
+    this.value = value;
+  }
+
+  @Override
+  Object evaluate(EvaluationContext context) {
+    return value;
+  }
+}