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+/*
+ * Copyright (c) 2003-2008, John Wiegley.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in the
+ *   documentation and/or other materials provided with the distribution.
+ *
+ * - Neither the name of New Artisans LLC nor the names of its
+ *   contributors may be used to endorse or promote products derived from
+ *   this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _PREDICATE_H
+#define _PREDICATE_H
+
+#include "expr.h"
+#include "scope.h"
+
+namespace ledger {
+
+template <typename T>
+class item_predicate
+{
+public:
+  expr_t predicate;
+
+  item_predicate() {
+    TRACE_CTOR(item_predicate, "");
+  }
+  item_predicate(const item_predicate& other) : predicate(other.predicate) {
+    TRACE_CTOR(item_predicate, "copy");
+  }
+  item_predicate(const expr_t& _predicate) : predicate(_predicate) {
+    TRACE_CTOR(item_predicate, "const expr_t&");
+  }
+  item_predicate(const string& _predicate) : predicate(expr_t(_predicate)) {
+    TRACE_CTOR(item_predicate, "const string&");
+  }
+  ~item_predicate() throw() {
+    TRACE_DTOR(item_predicate);
+  }
+
+  bool operator()(T& item) {
+    return ! predicate || predicate.calc(item).strip_annotations();
+  }
+};
+
+} // namespace ledger
+
+#endif // _PREDICATE_H