DISTINCT is now inside AST; tradeoff: [Return object with return list and distinct pointers -> query executor is going to be more complex] OR [ReturnList object and ReturnDistinct object -> lemon / LARL(1) syntax will be much more complex]

cypher/Makefile

@@ -1,5 +1,6 @@
 CXX = clang++
 CXXFLAGS = -std=c++1y
+# CXXFLAGS = -std=c++1y -g # DEBUG CXXFLAGS
 INC = -I../
 
 parser: parser.o cypher.o

cypher/ast/ast.hpp

@@ -7,6 +7,7 @@
 #include "property.hpp"
 #include "relationship.hpp"
 #include "node.hpp"
+#include "distinct.hpp"
 #include "return.hpp"
 #include "pattern.hpp"
 #include "return.hpp"

cypher/ast/ast_visitor.hpp

@@ -44,6 +44,7 @@ struct Pattern;
 
 struct Return;
 struct ReturnList;
+struct Distinct;
 
 struct Match;
 struct Where;
@@ -58,6 +59,6 @@ struct AstVisitor : public Visitor<Accessor, Boolean, Float, Identifier,
     Integer, String, Property, And, Or, Lt, Gt, Ge, Le, Eq, Ne, Plus, Minus,
     Star, Slash, Rem, PropertyList, RelationshipList, Relationship, Node,
     RelationshipSpecs, LabelList, ReturnList, Pattern, Match, ReadQuery,
-    Start, Where, WriteQuery, Create, Return> {};
+    Start, Where, WriteQuery, Create, Return, Distinct> {};
 
 }

cypher/ast/distinct.hpp

@@ -0,0 +1,17 @@
+#pragma once
+
+#include "ast_node.hpp"
+#include "identifier.hpp"
+
+namespace ast
+{
+
+struct Distinct : public AstNode<Distinct>
+{
+    Distinct(Identifier* identifier)
+        : identifier(identifier) {}
+
+    Identifier* identifier;
+};
+
+}

cypher/ast/expr.hpp

@@ -5,7 +5,9 @@
 namespace ast
 {
 
-struct Expr : public AstVisitable {};
+struct Expr : public AstVisitable
+{
+};
 
 template <class Derived>
 struct VisitableExpr : public Crtp<Derived>, public Expr

cypher/ast/return.hpp

@@ -2,6 +2,7 @@
 
 #include "list.hpp"
 #include "identifier.hpp"
+#include "distinct.hpp"
 
 namespace ast
 {
@@ -14,9 +15,17 @@ struct ReturnList : public List<Identifier, ReturnList>
 struct Return : public AstNode<Return>
 {
     Return(ReturnList* return_list)
-        : return_list(return_list) {}
+        : return_list(return_list), distinct(nullptr)
+    {
+    }
+
+    Return(Distinct* distinct)
+        : return_list(nullptr), distinct(distinct)
+    {
+    }
 
     ReturnList* return_list;
+    Distinct* distinct;
 };
 
 };

cypher/cypher.y

@@ -13,7 +13,14 @@
 
 %syntax_error
 {
-    throw SyntaxError(TOKEN->value);
+    int n = sizeof(yyTokenName) / sizeof(yyTokenName[0]);
+    for (int i = 0; i < n; ++i) {
+            int a = yy_find_shift_action(yypParser, (YYCODETYPE)i);
+            if (a < YYNSTATE + YYNRULE) {
+                    printf("possible token: %s\n", yyTokenName[i]);
+            }
+    }
+    // throw SyntaxError(TOKEN->value);
 }
 
 %stack_overflow
@@ -195,11 +202,14 @@ where_clause(W) ::= . {
 
 %type return_clause {ast::Return*}
 
-// return clause (return ORDER BY, SKIP, LIMIT)
 return_clause(R) ::= RETURN return_list(L). {
     R = ast->create<ast::Return>(L);
 }
 
+return_clause(R) ::= RETURN distinct(D). {
+    R = ast->create<ast::Return>(D);
+}
+
 %type return_list {ast::ReturnList*}
 
 return_list(R) ::= return_list(N) COMMA idn(I). {
@@ -210,6 +220,12 @@ return_list(R) ::= idn(I). {
     R = ast->create<ast::ReturnList>(I, nullptr);
 }
 
+%type distinct {ast::Distinct*}
+
+distinct(R) ::= DISTINCT idn(I). {
+    R = ast->create<ast::Distinct>(I);
+}
+
 %type properties {ast::PropertyList*}
 
 // '{' <property_list> '}'

cypher/cypher_lexer.hpp

@@ -48,6 +48,7 @@ public:
         rule("(?i:WHERE)", TK_WHERE);
         rule("(?i:RETURN)", TK_RETURN);
         rule("(?i:CREATE)", TK_CREATE);
+        rule("(?i:DISTINCT)", TK_DISTINCT);
 
         rule("(?i:AND)", TK_AND);
         rule("(?i:OR)", TK_OR);

cypher/debug/tree_print.hpp

@@ -124,6 +124,12 @@ public:
         Traverser::visit(return_clause);
     }
 
+    void visit(ast::Distinct& distinct) override
+    {
+        auto entry = printer.advance("Distinct");
+        Traverser::visit(distinct);
+    }
+
     void visit(ast::Accessor& accessor) override
     {
         auto entry = printer.advance("Accessor");

cypher/parser.cpp

@@ -8,14 +8,11 @@
 #include "utils/command_line/arguments.hpp"
 #include "utils/string/filereader.hpp"
 
+#include "utils/terminate_handler.hpp"
+
 using std::cout;
 using std::endl;
 
-// * QUERY EXAMPLES *
-// "CREATE (n { name: 'Dominik', age: 24, role: 'CEO' }) return n"
-// "MATCH (user:User { name: 'Dominik', age: 8 + 4})-[has:HAS|IS|CAN { duration: 'PERMANENT'}]->(item:Item)--(shop)"
-// "MATCH (user:User { name: 'Dominik', age: 24})-[has:HAS]->(item:Item) WHERE item.name = 'XPS 13' AND item.price = 11999.99 RETURN user, has, item"
-
 // * INPUT ARGUMENTS *
 // -q -> query
 // -v -> visitor
@@ -33,11 +30,14 @@ std::string extract_query(const vector_str& arguments)
 
 int main(int argc, char *argv[])
 {
+    std::set_terminate(&terminate_handler);
+
     // arguments parsing
     auto arguments = all_arguments(argc, argv);
 
     // query extraction
     auto cypher_query = extract_query(arguments);
+    cout << "QUERY: " << cypher_query << endl;
 
     // traversers
     auto traverser = get_argument(arguments, "-t", "code");

cypher/parser.hpp

@@ -35,7 +35,7 @@ public:
         {
             tokens.emplace_back(tokenizer.lookup());
             auto& token = tokens.back();
-            // std::cout << token << std::endl;
+            std::cout << token << std::endl;
             cypher_parser(parser, token.id, &token, &tree);
 
         } while(tokens.back().id != 0);

cypher/query/read/match/match-custom1.cypher

@@ -0,0 +1 @@
+MATCH (user:User { name: 'Dominik', age: 8 + 4})-[has:HAS|IS|CAN { duration: 'PERMANENT'}]->(item:Item)--(shop)

cypher/query/read/match/match-custom2.cypher

@@ -0,0 +1 @@
+MATCH (user:User { name: 'Dominik', age: 24})-[has:HAS]->(item:Item) WHERE item.name = 'XPS 13' AND item.price = 11999.99 RETURN user, has, item

cypher/query/read/return/return-alias.cypher

@@ -0,0 +1 @@
+MATCH (n) RETURN n AS columnName

cypher/query/read/return/return-all.cypher

@@ -0,0 +1 @@
+MATCH (n) RETURN n

cypher/query/read/return/return-count.cypher

@@ -0,0 +1 @@
+RETURN count(*)

cypher/query/read/return/return-distinct.cypher

@@ -0,0 +1 @@
+MATCH (n) RETURN DISTINCT n

cypher/query/read/return/return-limit.cypher

@@ -0,0 +1 @@
+LIMIT 10

cypher/query/read/return/return-order-asc.cypher

@@ -0,0 +1 @@
+ORDER BY n.property

cypher/query/read/return/return-order-desc.cypher

@@ -0,0 +1 @@
+ORDER BY n.property DESC

cypher/query/read/return/return-skip-limit.cypher

@@ -0,0 +1 @@
+SKIP 2 LIMIT 3

cypher/query/read/return/return-skip.cypher

@@ -0,0 +1 @@
+SKIP 10

cypher/query/read/union/union-all.cypher

@@ -0,0 +1 @@
+MATCH (a)-[:KNOWS]->(b) RETURN b.name UNION ALL MATCH (a)-[:LOVES]->(b) RETURN b.name

cypher/query/read/union/union.cypher

@@ -0,0 +1 @@
+MATCH (a)-[:KNOWS]->(b) RETURN b.name UNION MATCH (a)-[:LOVES]->(b) RETURN b.name

cypher/query/read/where/where.cypher

@@ -1 +1 @@
-WHERE  n.property <> {value}
+MATCH n WHERE n.property <> "100"

cypher/query/write/create-return.cypher

@@ -1 +1 @@
-CREATE (n {name: 'Domko', age: 24}) RETURN n
+CREATE (n {name: 'Domko', age: 26}) RETURN n

cypher/visitor/traverser.hpp

@@ -44,7 +44,10 @@ public:
 
     void visit(ast::Return& return_clause) override
     {
+        if (return_clause.return_list != nullptr)
             accept(return_clause.return_list);
+        if (return_clause.distinct != nullptr)
+            accept(return_clause.distinct);
     }
 
     void visit(ast::Accessor& accessor) override
@@ -188,6 +191,11 @@ public:
         accept(create.pattern);
     }
 
+    void visit(ast::Distinct& distinct) override
+    {
+        accept(distinct.identifier);
+    }
+
 protected:
     template<class T>
     void accept(T* node)

memgraph.cpp

@@ -23,8 +23,8 @@ int main()
     container.singleton<Db>();
 
     auto loop = container.singleton<uv::UvLoop>();
-    auto app = container.singleton<sp::Speedy, uv::UvLoop>("/db/data");
 
+    auto app = container.singleton<sp::Speedy, uv::UvLoop>("/db/data");
     container.singleton<Pool>(4);
     container.singleton<Task, uv::UvLoop, Pool>();