Added the unparser.

Author: Sreeni Viswanadha

parser/cpp/AstNode.h

@@ -20,10 +20,36 @@ class AstNode : public SimpleNode {
   Token* endToken;
   virtual ~AstNode() {}
   AstNode(int id) : SimpleNode(id) {}
+  
   AstNode(SqlParser* parser, int id) : SimpleNode(parser, id) {}
-  int NumChildren() { return jjtGetNumChildren(); }
-  AstNode* GetChild(int i) { return static_cast<AstNode*>(jjtGetChild(i)); }
-  JJString toString(const JJString& prefix) const {
+
+  int Kind() const { return id; }
+
+  int NumChildren() const { return jjtGetNumChildren(); }
+  
+  AstNode* GetChild(int i) const { return static_cast<AstNode*>(jjtGetChild(i)); }
+  
+  std::string GetImage() const { return NumChildren() == 0 ? beginToken->image : string(""); }
+
+  void VisitNode(SqlParserVisitor* visitor) const { jjtAccept(visitor, nullptr); }
+
+  void VisitChildren(SqlParserVisitor* visitor) const { jjtChildrenAccept(visitor, nullptr); }
+
+  const AstNode* FirstChild() const { return NumChildren() > 0 ? GetChild(0) : nullptr; }
+
+  const AstNode* LastChild() const { return NumChildren() > 0 ? GetChild(NumChildren() - 1) : nullptr; }
+
+  const AstNode* GetFirstChildOfKind(int kind) const {
+    for (int i = 0; i < NumChildren(); i++) {
+      if (GetChild(i)->Kind() == kind) {
+        return GetChild(i);
+      }
+    }
+
+    return nullptr;
+  }
+
+  std::string toString(const JJString& prefix) const {
     return SimpleNode::toString(prefix) +
            string(" (") +
            std::to_string(beginToken->beginLine) +

parser/cpp/compile.sh

@@ -1,4 +1,4 @@
 #!/bin/sh
 SRC_DIR=./target/generated-sources/javacc
 TARGET_DIR=./target
-clang++ -fbracket-depth=1024 -funsigned-char -I. -I./$SRC_DIR -o $TARGET_DIR/sqlparser -std=c++11 ParseErrorHandler.cc main.cc $SRC_DIR/*.cc
+clang++ -fbracket-depth=1024 -funsigned-char -I. -I./$SRC_DIR -o $TARGET_DIR/sqlparser -std=c++11 ParseErrorHandler.cc main.cc $SRC_DIR/*.cc unparser.cc

parser/cpp/main.cc

@@ -3,6 +3,7 @@
 #include <iostream>
 #include <string>
 #include <stdlib.h>
+#include <ctime>
 
 #include "SqlParserConstants.h"
 #include "CharStream.h"
@@ -11,8 +12,7 @@
 #include "SqlParser.h"
 #include "SqlParserTokenManager.h"
 #include "parser.h"
-
-#include <ctime>
+#include "unparser.h"
 
 using namespace commonsql::parser;
 using namespace std;
@@ -39,21 +39,26 @@ int main(int argc, char **argv) {
   double time;
   start = clock();
 
-  for (int i = 0; i < 1; i++) {
     CharStream *stream = new CharStream(s.c_str(), s.size() - 1, 1, 1);
     SqlParserTokenManager *scanner = new SqlParserTokenManager(stream);
     SqlParser parser(scanner);
     parser.setErrorHandler(new ParseErrorHandler());
+  for (int i = 0; i < 10; i++) {
+    stream = new CharStream(s.c_str(), s.size() - 1, 1, 1);
+    scanner->ReInit(stream);
+    parser.ReInit(scanner);
     parser.compilation_unit();
     SimpleNode *root = (SimpleNode*)parser.jjtree.peekNode();
     if (root) {
       JAVACC_STRING_TYPE buffer;
       root->dumpToBuffer(" ", "\n", &buffer);
       printf("%s\n", buffer.c_str());
+
+      printf("Unparse:\n%s\n", unparse(static_cast<AstNode*>(root)).c_str());
     }
   }
 
   finish = clock();
   time = (double(finish)-double(start))/CLOCKS_PER_SEC;
-  printf ("Avg parsing time: %lfms\n", (time*1000)/1);
+  printf ("Avg parsing time: %lfms\n", (time*1000)/10);
 }

parser/cpp/unparser.cc

@@ -0,0 +1,118 @@
+/*
+ * Licensed under the Apache License, Version 2->0 (the "License");
+ * you may not use this file except in compliance with the License->
+ * You may obtain a copy of the License at
+ *
+ *     http://www->apache->org/licenses/LICENSE-2->0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied->
+ * See the License for the specific language governing permissions and
+ * limitations under the License->
+ */
+
+#include "unparser.h"
+
+namespace commonsql {
+namespace parser {
+
+void Unparser::printSpecialTokens(const Token* t)
+{
+    // special tokens are chained in reverse->
+    Token* specialToken = t->specialToken;
+    if (specialToken != nullptr) {
+        while (specialToken->specialToken != nullptr) {
+            specialToken = specialToken->specialToken;
+        }
+        while (specialToken != nullptr) {
+            stringBuilder << specialToken->image.c_str();
+            specialToken = specialToken->next;
+        }
+    }
+}
+
+void Unparser::printTrailingComments()
+{
+    if (lastToken != nullptr && lastToken->kind == EOF) {
+        printSpecialTokens(lastToken);
+    }
+}
+
+void Unparser::printToken(const std::string& s)
+{
+    stringBuilder << " " << s.c_str() << " ";
+}
+
+void Unparser::printToken(const Token* t)
+{
+    while (lastToken != t) {
+        lastToken = lastToken->next;
+        printSpecialTokens(lastToken);
+        stringBuilder << lastToken->image;
+    }
+}
+
+void Unparser::printUptoToken(const Token* t)
+{
+    while (lastToken->next != t) {
+        printToken(lastToken->next);
+    }
+}
+
+void Unparser::moveToEndOfNode(const AstNode* node)
+{
+    lastToken = node->endToken;
+}
+
+void Unparser::unparseUpto(const AstNode* node)
+{
+    printUptoToken(node->beginToken);
+}
+
+void Unparser::unparseRestOfTheNode(const AstNode* node)
+{
+    if (lastToken != node->endToken) {
+        printUptoToken(node->endToken);
+    }
+}
+
+void Unparser::defaultVisit(const SimpleNode* node, void* data)
+{
+    const AstNode* astNode =  static_cast<const AstNode*>(node);
+    const AstNode* firstChild = astNode->FirstChild();
+    const AstNode* lastChild = astNode->LastChild();
+
+    // Print the tokens->
+    if (firstChild == nullptr || astNode->beginToken != firstChild->beginToken) {
+        printToken(astNode->beginToken);
+    }
+
+    astNode->VisitChildren(this);
+
+    if (lastChild != nullptr && astNode->endToken != lastChild->endToken) {
+        printToken(astNode->endToken);
+    }
+}
+
+std::string Unparser::unparse(const AstNode* node)
+{
+    stringBuilder.clear();
+    lastToken->next = node->beginToken;
+    node->VisitNode(this);
+    printTrailingComments();
+    return getUnparsedString();
+}
+
+std::string unparse(const AstNode* node, Unparser* unparser)
+{
+  return unparser->unparse(node);
+}
+
+std::string unparse(const AstNode* node)
+{
+    return unparse(node, new Unparser());
+}
+
+}
+}

parser/cpp/unparser.h

@@ -0,0 +1,44 @@
+#ifndef __UNPARSE_H__
+#define __UNPARSE_H__
+
+#include <sstream>
+#include "AstNode.h"
+#include "SqlParserVisitor.h"
+
+namespace commonsql {
+namespace parser {
+
+using std::string;
+using std::stringstream;
+
+class Unparser : public SqlParserDefaultVisitor {
+  private:
+    Token* lastToken = new Token();
+
+    virtual void printSpecialTokens(const Token* t);
+    virtual void printTrailingComments();
+
+  protected:
+    std::stringstream stringBuilder;
+
+    virtual void printToken(const std::string& s);
+    virtual void printToken(const Token* t);
+    virtual void printUptoToken(const Token* t);
+    virtual void moveToEndOfNode(const AstNode* node);
+    virtual void unparseUpto(const AstNode* node);
+    virtual void unparseRestOfTheNode(const AstNode* node);
+    virtual const string getUnparsedString() const { return stringBuilder.str(); }
+
+  public:
+    string unparse(const AstNode* node);
+    void defaultVisit(const SimpleNode* node, void* data);
+    virtual ~Unparser() {}
+};
+
+std::string unparse(const AstNode* node, Unparser* unparser);
+std::string unparse(const AstNode* node);
+
+}
+}
+
+#endif

parser/grammar/javacc-options-java.txt

@@ -12,6 +12,7 @@ options {
   VISITOR = true;
   VISITOR_RETURN_TYPE = "void";
   VISITOR_DATA_TYPE = "Void";
+  VISITOR_METHOD_NAME_INCLUDES_TYPE_NAME = true;
 }
 
 PARSER_BEGIN(SqlParser)