dressipi usecase hardcoded

src/barrier/barrier.cpp

@@ -674,6 +674,12 @@ void RecordStream<Stream>::write_meta(const std::string &type)
     HALF_CALL(write_meta(type));
 }
 
+template <class Stream>
+void RecordStream<Stream>::write_failure(const std::map<std::string, std::string> &data)
+{
+    HALF_CALL(write_failure(data));
+}
+
 template <class Stream>
 void RecordStream<Stream>::send()
 {

src/cypher/ast/ast.hpp

@@ -19,3 +19,4 @@
 #include "set.hpp"
 #include "expr.hpp"
 #include "with.hpp"
+#include "functions.hpp"

src/cypher/ast/ast_visitor.hpp

@@ -36,6 +36,9 @@ struct Star;
 struct Slash;
 struct Rem;
 
+// functions
+struct CountFunction;
+
 struct RelationshipSpecs;
 struct RelationshipTypeList;
 struct Relationship;
@@ -83,6 +86,7 @@ struct AstVisitor
           PatternList, Match, ReadQuery, Start, Where, WriteQuery, Create,
           Return, Distinct, Delete, DeleteQuery, UpdateQuery, Set, SetKey,
           ReadWriteQuery, IdentifierList, WithList, WithClause, WithQuery, Long,
+          CountFunction,
           InternalIdExpr, SetValue, SetElement, SetList>
 {
 };

src/cypher/ast/expr.hpp

@@ -24,6 +24,16 @@ struct LeafExpr : public ValueExpr<Derived>
     T value;
 };
 
+// T is argument type
+template <class T, class Derived>
+struct FunctionExpr : public ValueExpr<Derived>
+{
+    FunctionExpr(const std::string& name, T argument) : name(name), argument(argument) {}
+    
+    std::string name;
+    T argument;
+};
+
 template <class Derived>
 struct BinaryExpr : public ValueExpr<Derived>
 {
@@ -43,4 +53,5 @@ struct PatternExpr : public Expr
 
     Pattern *pattern;
 };
+
 }

src/cypher/ast/functions.hpp

@@ -0,0 +1,14 @@
+#pragma once
+
+#include "expr.hpp"
+
+namespace ast
+{
+
+struct CountFunction : public FunctionExpr<std::string, CountFunction>
+{
+    CountFunction(const std::string &argument) : FunctionExpr("count", argument)
+    {
+    }
+};
+}

src/cypher/cypher.y

@@ -495,6 +495,12 @@ pattern_expr(E) ::= pattern(P). {
     E = ast->create<ast::PatternExpr>(P);
 }
 
+%type function_expr {ast::Expr*}
+
+function_expr(E) ::= COUNT LP IDN(A) RP. {
+    E = ast->create<ast::CountFunction>(A->value);
+}
+
 %type expr {ast::Expr*}
 
 expr(E) ::= value_expr(V). {
@@ -505,6 +511,10 @@ expr(E) ::= pattern_expr(P). {
     E = P;
 }
 
+expr(E) ::= function_expr(F). {
+    E = F;
+}
+
 //%type alias {ast::Alias*}
 //
 //alias(A) ::= IDN(X) AS IDN(Y). {

src/cypher/debug/tree_print.hpp

@@ -294,6 +294,12 @@ public:
         Traverser::visit(rem);
     }
 
+    void visit(ast::CountFunction& count) override
+    {
+        auto entry = printer.advance("Count ");
+        entry << count.name << "(" << count.argument << ")";
+    }
+
     void visit(ast::PropertyList& prop_list) override
     {
         auto entry = printer.advance("Property List");

src/cypher/tokenizer/cypher_lexer.hpp

@@ -58,6 +58,9 @@ public:
         rule("(?i:AND)", TK_AND);
         rule("(?i:OR)", TK_OR);
 
+        // functions
+        rule("(?i:COUNT)", TK_COUNT);
+
         // string literal TODO single quote escape
         rule("'(.*?)'", TK_STR);
 

src/cypher/visitor/traverser.hpp

@@ -154,6 +154,10 @@ public:
         accept(rem.right);
     }
 
+    void visit(ast::CountFunction& count) override
+    {
+    }
+
     void visit(ast::PropertyList& prop_list) override
     {
         accept(prop_list.value);