Merge pull request #17 from m-peko/expression-tree-class

Expression tree class

README.md

@@ -162,9 +162,9 @@ int main() {
 
     booleval::evaluator evaluator;
 
-    auto success = evaluator.build_expression_tree("field_a foo and field_b 123");
-    if (!success) {
-        std::cerr << "Error while building expression tree!" << std::endl;
+    auto valid = evaluator.expression("field_a foo and field_b 123");
+    if (!valid) {
+        std::cerr << "Expression not valid!" << std::endl;
     }
 
     if (evaluator.is_activated()) {

include/booleval/evaluator.h

@@ -31,12 +31,10 @@
 #define BOOLEVAL_EVALUATOR_H
 
 #include <map>
-#include <memory>
 #include <string_view>
-#include <booleval/node/tree_node.h>
 #include <booleval/utils/any_value.h>
-#include <booleval/token/tokenizer.h>
-#include <booleval/node/result_visitor.h>
+#include <booleval/tree/result_visitor.h>
+#include <booleval/tree/expression_tree.h>
 
 namespace booleval {
 
@@ -68,13 +66,13 @@ class evaluator {
     bool is_activated() const noexcept;
 
     /**
-     * Checks whether the expression tree is successfully built.
+     * Sets the expression to be used for evaluation.
      *
-     * @param expression Expression used for building the tree
+     * @param expression Expression to be used for evaluation
      *
-     * @return True if the tree is successfully built, otherwise false
+     * @return True if the expression is valid, otherwise false
      */
-    bool build_expression_tree(std::string_view expression);
+    bool expression(std::string_view expression);
 
     /**
      * Evaluates expression tree based on the key value map passed in.
@@ -85,47 +83,10 @@ class evaluator {
      */
     bool evaluate(field_map const& fields);
 
-private:
-    /**
-     * Parses logical operation OR.
-     *
-     * @return Root tree node for the current part of the expression
-     */
-    std::shared_ptr<node::tree_node> parse_expression();
-
-    /**
-     * Parses logical operation AND.
-     *
-     * @return Root tree node for the current part of the expression
-     */
-    std::shared_ptr<node::tree_node> parse_and_operation();
-
-    /**
-     * Parses new expression within parentheses.
-     *
-     * @return Root tree node for the parsed expression
-     */
-    std::shared_ptr<node::tree_node> parse_parentheses();
-
-    /**
-     * Parses relational operation (EQ, NEQ, GT, LT, ...).
-     *
-     * @return Root tree node for the parsed operation
-     */
-    std::shared_ptr<node::tree_node> parse_relational_operation();
-
-    /**
-     * Parses terminal, i.e. field token.
-     *
-     * @return Leaf node
-     */
-    std::shared_ptr<node::tree_node> parse_terminal();
-
 private:
     bool is_activated_;
-    token::tokenizer tokenizer_;
-    std::shared_ptr<node::tree_node> root_;
-    node::result_visitor result_visitor_;
+    tree::result_visitor result_visitor_;
+    tree::expression_tree expression_tree_;
 };
 
 } // booleval

include/booleval/node/base_visitor.h → include/booleval/tree/base_visitor.h

@@ -30,12 +30,12 @@
 #ifndef BOOLEVAL_BASE_VISITOR_H
 #define BOOLEVAL_BASE_VISITOR_H
 
-#include <booleval/node/tree_node.h>
+#include <booleval/tree/tree_node.h>
 #include <booleval/token/token_type.h>
 
 namespace booleval {
 
-namespace node {
+namespace tree {
 
 /**
  * class base_visitor
@@ -174,7 +174,7 @@ ReturnType base_visitor<ReturnType>::visit(tree_node const& node) {
     }
 }
 
-} // node
+} // tree
 
 } // booleval
 

include/booleval/tree/expression_tree.h

@@ -0,0 +1,120 @@
+/*
+ * Copyright (c) 2020, Marin Peko
+ * 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.
+ *
+ * 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 BOOLEVAL_EXPRESSION_TREE_H
+#define BOOLEVAL_EXPRESSION_TREE_H
+
+#include <memory>
+#include <string_view>
+#include <booleval/tree/tree_node.h>
+#include <booleval/token/tokenizer.h>
+
+namespace booleval {
+
+namespace tree {
+
+/**
+ * class expression_tree
+ *
+ * Represents a class for building an expression tree by using a recursive
+ * descent parser method.
+ */
+class expression_tree {
+public:
+    expression_tree();
+    expression_tree(expression_tree&& rhs) = default;
+    expression_tree(expression_tree const& rhs) = default;
+
+    expression_tree& operator=(expression_tree&& rhs) = default;
+    expression_tree& operator=(expression_tree const& rhs) = default;
+
+    ~expression_tree() = default;
+
+    /**
+     * Gets the root tree node.
+     *
+     * @return Root tree node
+     */
+    std::shared_ptr<tree::tree_node> root() noexcept;
+
+    /**
+     * Builds the expression tree.
+     *
+     * @param expression Expression to build the tree for
+     *
+     * @return True if the expression tree is built successfully, otherwise false
+     */
+    bool build(std::string_view expression);
+
+private:
+    /**
+     * Parses root expression by trying first to parse logical operation OR.
+     *
+     * @return Root tree node for the current part of the expression
+     */
+    std::shared_ptr<tree::tree_node> parse_expression();
+
+    /**
+     * Parses logical operation AND.
+     *
+     * @return Root tree node for the parsed logical operation
+     */
+    std::shared_ptr<tree::tree_node> parse_and_operation();
+
+    /**
+     * Parses new expression within parentheses.
+     *
+     * @return Root tree node for the parsed expression within parentheses
+     */
+    std::shared_ptr<tree::tree_node> parse_parentheses();
+
+    /**
+     * Parses relational operation (EQ, NEQ, GT, LT, GEQ and LEQ).
+     *
+     * @return Root tree node for the parsed relational operation
+     */
+    std::shared_ptr<tree::tree_node> parse_relational_operation();
+
+    /**
+     * Parses terminal.
+     *
+     * @return Leaf node
+     */
+    std::shared_ptr<tree::tree_node> parse_terminal();
+
+private:
+    token::tokenizer tokenizer_;
+    std::shared_ptr<tree::tree_node> root_;
+};
+
+} // tree
+
+} // booleval
+
+#endif // BOOLEVAL_EXPRESSION_TREE_H

include/booleval/node/result_visitor.h → include/booleval/tree/result_visitor.h

@@ -32,13 +32,13 @@
 
 #include <map>
 #include <string_view>
-#include <booleval/node/tree_node.h>
+#include <booleval/tree/tree_node.h>
 #include <booleval/utils/any_value.h>
-#include <booleval/node/base_visitor.h>
+#include <booleval/tree/base_visitor.h>
 
 namespace booleval {
 
-namespace node {
+namespace tree {
 
 /**
  * class result_visitor
@@ -149,7 +149,7 @@ class result_visitor : public base_visitor<bool> {
     field_map fields_;
 };
 
-} // node
+} // tree
 
 } // booleval
 

include/booleval/node/tree_node.h → include/booleval/tree/tree_node.h

@@ -36,7 +36,7 @@
 
 namespace booleval {
 
-namespace node {
+namespace tree {
 
 /**
  * struct tree_node
@@ -61,7 +61,7 @@ struct tree_node {
     ~tree_node() = default;
 };
 
-} // node
+} // tree
 
 } // booleval
 

src/CMakeLists.txt

@@ -7,13 +7,14 @@ include_directories (
 
 set (
     SOURCE_FILES
-        node/result_visitor.cpp
-        node/tree_node.cpp
-
         token/token.cpp
         token/token_type.cpp
         token/tokenizer.cpp
 
+        tree/expression_tree.cpp
+        tree/result_visitor.cpp
+        tree/tree_node.cpp
+
         utils/any_value.cpp
         utils/string_utils.cpp
 
@@ -22,14 +23,15 @@ set (
 
 set (
     INCLUDE_FILES
-        ${BOOLEVAL_INCLUDE_DIR}/booleval/node/base_visitor.h
-        ${BOOLEVAL_INCLUDE_DIR}/booleval/node/result_visitor.h
-        ${BOOLEVAL_INCLUDE_DIR}/booleval/node/tree_node.h
-
         ${BOOLEVAL_INCLUDE_DIR}/booleval/token/token.h
         ${BOOLEVAL_INCLUDE_DIR}/booleval/token/token_type.h
         ${BOOLEVAL_INCLUDE_DIR}/booleval/token/tokenizer.h
 
+        ${BOOLEVAL_INCLUDE_DIR}/booleval/tree/base_visitor.h
+        ${BOOLEVAL_INCLUDE_DIR}/booleval/tree/expression_tree.h
+        ${BOOLEVAL_INCLUDE_DIR}/booleval/tree/result_visitor.h
+        ${BOOLEVAL_INCLUDE_DIR}/booleval/tree/tree_node.h
+
         ${BOOLEVAL_INCLUDE_DIR}/booleval/utils/any_value.h
         ${BOOLEVAL_INCLUDE_DIR}/booleval/utils/string_utils.h