1 files changed, 98 insertions, 0 deletions
diff --git a/src/main/java/io/devnulllabs/openjava/syntax/SeparatedListRule.java b/src/main/java/io/devnulllabs/openjava/syntax/SeparatedListRule.java
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+++ b/src/main/java/io/devnulllabs/openjava/syntax/SeparatedListRule.java
@@ -0,0 +1,98 @@
+/*
+ * SeparatedListRule.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>SeparatedListRule</code> represents the syntax
+ * rule of a list separated by an separator.
+ * <p>
+ * Suppose there's a syntax rule A and token t.  This class can
+ * represents the syntax A ( t A )*.
+ * <p>
+ *
+ * @author   Michiaki Tatsubori
+ * @version  1.0
+ * @since    $Id: SeparatedListRule.java,v 1.2 2003/02/19 02:54:32 tatsubori Exp $
+ * @see java.lang.Object
+ */
+public abstract class SeparatedListRule extends AbstractSyntaxRule {
+    private SyntaxRule elementRule;
+    private int separator;
+    private boolean allowsEmpty;
+
+    protected abstract void initList();
+    protected abstract void addListElement(Object elem);
+    protected abstract ParseTree getList();
+
+    /**
+     * Allocates a new rule representing a list of a give rule
+     * separeted by a given separator.
+     *
+     * @param elementRule a rule of each element of the list
+     * @param separator_token  the id of a token to be separator
+     * @param allowEmpty a flag to allow 0 iteration if it is true.
+     * @see io.devnulllabs.openjava.syntax.TokenID
+     */
+    public SeparatedListRule(
+        SyntaxRule elementRule,
+        int separator_token,
+        boolean allowsEmpty) {
+        this.elementRule = elementRule;
+        this.separator = separator_token;
+        this.allowsEmpty = allowsEmpty;
+    }
+
+    /**
+     * Allocates a new rule representing a list of a give rule
+     * separeted by a given separator.
+     *
+     * @param elementRule a rule of each element of the list
+     * @param separator_token  the id of a token to be separator
+     * @see io.devnulllabs.openjava.syntax.TokenID
+     */
+    public SeparatedListRule(SyntaxRule elementRule, int separator_token) {
+        this(elementRule, separator_token, false);
+    }
+
+    /**
+     * Consumes token source.
+     *
+     * @param token_src  token source.
+     * @return  null if this fails to consume a syntax tree represented
+     * by this object.  Otherwise it returns <code>ObjectList</code> object.
+     */
+    public final ParseTree consume(TokenSource token_src)
+        throws SyntaxException {
+        initList();
+        ParseTree elem;
+        if (!allowsEmpty) {
+            elem = elementRule.consume(token_src);
+            addListElement(elem);
+        }
+        CompositeRule spy =
+            new CompositeRule(new TokenRule(separator), elementRule);
+        while (spy.lookahead(token_src)) {
+            elem = consumeSepAndElem(token_src);
+            addListElement(elem);
+        }
+        return getList();
+    }
+
+    private ParseTree consumeSepAndElem(TokenSource token_src)
+        throws SyntaxException {
+        token_src.getNextToken(); /* separator */
+        return elementRule.consume(token_src);
+    }
+
+}