Code maintenance and fixes

1 files changed, 58 insertions, 0 deletions

diff --git a/dice-lang/src/main/java/bjc/dicelang/ast/DiceASTDefinedChecker.java b/dice-lang/src/main/java/bjc/dicelang/ast/DiceASTDefinedChecker.java
new file mode 100644
index 0000000..247054a
--- /dev/null
+++ b/dice-lang/src/main/java/bjc/dicelang/ast/DiceASTDefinedChecker.java
@@ -0,0 +1,58 @@
+package bjc.dicelang.ast;
+
+import java.util.Map;
+import java.util.function.Consumer;
+
+import bjc.utils.data.IHolder;
+
+/**
+ * Check if the specified node references a particular variable
+ * 
+ * @author ben
+ *
+ */
+public final class DiceASTDefinedChecker
+		implements Consumer<IDiceASTNode> {
+	/**
+	 * This is true if the specified node references the set variable
+	 */
+	private IHolder<Boolean>				referencesVariable;
+
+	private Map<String, DiceASTExpression>	enviroment;
+
+	/**
+	 * Create a new reference checker
+	 * 
+	 * @param referencesVar
+	 *            The holder of whether the variable is referenced or not
+	 * @param env
+	 *            The enviroment to check undefinedness against
+	 */
+	public DiceASTDefinedChecker(IHolder<Boolean> referencesVar,
+			Map<String, DiceASTExpression> env) {
+		this.referencesVariable = referencesVar;
+		this.enviroment = env;
+	}
+
+	@Override
+	public void accept(IDiceASTNode astNode) {
+		referencesVariable.transform((bool) -> checkUndefined(astNode));
+	}
+
+	/**
+	 * Check if a given AST node references an undefined variable
+	 * 
+	 * @param astNode
+	 *            The node to check
+	 * @return Whether or not the node directly the variable
+	 */
+	private boolean checkUndefined(IDiceASTNode astNode) {
+		if (astNode.getType() == DiceASTType.VARIABLE) {
+			VariableDiceNode node = (VariableDiceNode) astNode;
+
+			return !enviroment.containsKey(node.getVariable());
+		} else {
+			return false;
+		}
+	}
+}
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