1 files changed, 61 insertions, 0 deletions
diff --git a/src/main/java/io/devnulllabs/openjava/syntax/SelectionRule.java b/src/main/java/io/devnulllabs/openjava/syntax/SelectionRule.java
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+++ b/src/main/java/io/devnulllabs/openjava/syntax/SelectionRule.java
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+/*
+ * SelectionRule.java
+ *
+ * comments here.
+ *
+ * @author   Michiaki Tatsubori
+ * @version  %VERSION% %DATE%
+ * @see      java.lang.Object
+ *
+ * COPYRIGHT 1998 by Michiaki Tatsubori, ALL RIGHTS RESERVED.
+ */
+package io.devnulllabs.openjava.syntax;
+
+import io.devnulllabs.openjava.ptree.ParseTree;
+
+/**
+ * The class <code>SelectionRule</code> represents selective syntax
+ * rule.
+ * <p>
+ * Suppose there're several syntax rules; A, B, C.  This class
+ * can represents the syntax ( A | B | C ).
+ * If both A and B are adaptable to token source, A is choosed since
+ * A is specified at lefter part than B's part.
+ *
+ * @author   Michiaki Tatsubori
+ * @version  1.0
+ * @since    $Id: SelectionRule.java,v 1.2 2003/02/19 02:54:31 tatsubori Exp $
+ * @see java.lang.Object
+ */
+public class SelectionRule extends AbstractSyntaxRule {
+    protected SyntaxRule[] elementRules;
+
+    /**
+     * Allocates a new rule representing a selection of given rules.
+     *
+     * @param elementRules  an array of rules
+     */
+    public SelectionRule(SyntaxRule[] elementRules) {
+        this.elementRules = elementRules;
+    }
+
+    public SelectionRule(SyntaxRule e1, SyntaxRule e2) {
+        this(new SyntaxRule[] { e1, e2 });
+    }
+
+    public SelectionRule(SyntaxRule e1, SyntaxRule e2, SyntaxRule e3) {
+        this(new SyntaxRule[] { e1, e2, e3 });
+    }
+
+    public ParseTree consume(TokenSource token_src) throws SyntaxException {
+        for (int i = 0; i < elementRules.length; ++i) {
+            if (elementRules[i].lookahead(token_src)) {
+                ParseTree result = elementRules[i].consume(token_src);
+                return result;
+            }
+        }
+        /***** to become specifed error report */
+        throw new SyntaxException("neither of selection");
+    }
+
+}