src/knowledge_base.cpp

@@ -0,0 +1,59 @@
+#include "knowledge_base.h"
+
+#include <iostream>
+
+const std::string obelisk::Sql::create_facts_table
+    = "CREATE TABLE fact (id INT PRIMARY KEY NOT NULL);";
+
+obelisk::KnowledgeBase::KnowledgeBase(const char* filename)
+{
+    KnowledgeBase(filename, DEFAULT_FLAGS);
+}
+
+obelisk::KnowledgeBase::KnowledgeBase(const char* filename, int flags)
+{
+    filename_ = std::move(filename);
+    flags_    = std::move(flags);
+
+    auto result = sqlite3_open_v2(filename, &dbConnection_, flags, NULL);
+    if (result != SQLITE_OK)
+    {
+        logSqliteError(result);
+    }
+
+    char* tmp;
+    result = sqlite3_exec(dbConnection_,
+        obelisk::Sql::create_facts_table.c_str(),
+        NULL,
+        NULL,
+        &tmp);
+    if (tmp)
+    {
+        std::string errmsg(tmp);
+        throw obelisk::KnowledgeBaseException(errmsg);
+    }
+}
+
+obelisk::KnowledgeBase::~KnowledgeBase()
+{
+    sqlite3_close_v2(dbConnection_);
+}
+
+// TODO: log files?
+void obelisk::KnowledgeBase::logSqliteError(int result)
+{
+    std::cout << sqlite3_errstr(result) << std::endl;
+}
+
+void obelisk::KnowledgeBase::getFloat(float* result1,
+    float* result2,
+    double var)
+{
+    *result1 = (float) var;
+    *result2 = (float) (var - (double) *result1);
+}
+
+void obelisk::KnowledgeBase::getDouble(double* result, float var1, float var2)
+{
+    *result = (double) ((double) var2 + (double) var1);
+}

src/knowledge_base.h

@@ -0,0 +1,61 @@
+#ifndef OBELISK_KNOWLEDGE_BASE_H
+#define OBELISK_KNOWLEDGE_BASE_H
+
+#include <sqlite3.h>
+
+#include <iostream>
+#include <string>
+
+namespace obelisk
+{
+    class KnowledgeBase
+    {
+        private:
+            const int DEFAULT_FLAGS
+                = SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE;
+            const char* filename_;
+            sqlite3* dbConnection_;
+            int flags_;
+            void logSqliteError(int result);
+
+        public:
+            KnowledgeBase(const char* filename);
+            KnowledgeBase(const char* filename, int flags);
+            ~KnowledgeBase();
+
+            template<typename T, typename U>
+            int addFacts(std::string verb, T leftEntities, U rightEntities);
+            // TODO: add parameter for fact
+            template<typename T, typename U>
+            int addRules(std::string verb, T leftEntities, U rightEntities);
+            template<typename T, typename U> int addActions();
+
+            void getDouble(double* result, float var1, float var2);
+            void getFloat(float* result1, float* result2, double var);
+    };
+
+    class Sql
+    {
+        public:
+            static const std::string create_facts_table;
+    };
+
+    class KnowledgeBaseException : public std::exception
+    {
+        private:
+            std::string errorMessage_;
+
+        public:
+            KnowledgeBaseException(std::string errorMessage) :
+                errorMessage_(errorMessage)
+            {
+            }
+
+            const char* what() const noexcept
+            {
+                return errorMessage_.c_str();
+            }
+    };
+} // namespace obelisk
+
+#endif

src/meson.build

@@ -1,13 +1,17 @@
 obelisk_sources = files(
     'obelisk.cpp',
     'lexer.cpp',
-    'parser.cpp'
+    'parser.cpp',
+    'knowledge_base.cpp'
 )
 
+sqlite3 = dependency('sqlite3')
+
 subdir('ast')
 obelisk_sources += obelisk_ast_sources
 
 executable('obelisk',
     obelisk_sources,
+    dependencies : [sqlite3],
     install : true
 )

src/models/entity.cpp

@@ -0,0 +1,30 @@
+#include "models/entity.h"
+
+obelisk::Entity::Entity()
+{
+}
+
+obelisk::Entity::Entity(std::string name)
+{
+    name = name;
+}
+
+int obelisk::Entity::getId()
+{
+    return id_;
+}
+
+void obelisk::Entity::setId(int id)
+{
+    id_ = id;
+}
+
+std::string obelisk::Entity::getName()
+{
+    return name_;
+}
+
+void obelisk::Entity::setName(std::string name)
+{
+    name_ = name_;
+}

src/models/entity.h

@@ -0,0 +1,26 @@
+#ifndef OBELISK_MODELS_ENTITY_H
+#define OBELISK_MODELS_ENTITY_H
+
+#include <string>
+
+namespace obelisk
+{
+    class Entity
+    {
+        private:
+            int id_;
+            std::string name_;
+
+        public:
+            Entity();
+            Entity(std::string name);
+
+            int getId();
+            void setId(int id);
+
+            std::string getName();
+            void setName(std::string name);
+    };
+} // namespace obelisk
+
+#endif

src/models/verb.cpp

@@ -0,0 +1,36 @@
+#include "models/verb.h"
+
+obelisk::Verb::Verb()
+{
+}
+
+obelisk::Verb::Verb(std::string verb)
+{
+    verb_ = verb;
+}
+
+obelisk::Verb::Verb(int id, std::string verb)
+{
+    id_   = id;
+    verb_ = verb;
+}
+
+int obelisk::Verb::getId()
+{
+    return id_;
+}
+
+void obelisk::Verb::setId(int id)
+{
+    id_ = id;
+}
+
+std::string obelisk::Verb::getVerb()
+{
+    return verb_;
+}
+
+void obelisk::Verb::setVerb(std::string verb)
+{
+    verb_ = verb;
+}

src/models/verb.h

@@ -0,0 +1,27 @@
+#ifndef OBELISK_MODELS_VERB_H
+#define OBELISK_MODELS_VERB_H
+
+#include <string>
+
+namespace obelisk
+{
+    class Verb
+    {
+        private:
+            int id_;
+            std::string verb_;
+
+        public:
+            Verb();
+            Verb(std::string verb);
+            Verb(int id, std::string verb);
+
+            int getId();
+            void setId(int id);
+
+            std::string getVerb();
+            void setVerb(std::string verb);
+    };
+} // namespace obelisk
+
+#endif

src/obelisk.cpp

@@ -1,8 +1,11 @@
+#include "knowledge_base.h"
 #include "lexer.h"
 #include "obelisk.h"
 #include "parser.h"
 
+#include <iomanip>
 #include <iostream>
+#include <limits>
 
 static void mainLoop()
 {
@@ -44,6 +47,43 @@ int main(int argc, char** argv)
         std::cout << argv[i] << std::endl;
     }
 
+    try
+    {
+        obelisk::KnowledgeBase* kb = new obelisk::KnowledgeBase("cromer.kb");
+
+        /*std::vector<std::string> leftObjects;
+        std::vector<std::string> rightObjects;
+        leftObjects.push_back("chris");
+        leftObjects.push_back("martin");
+
+        rightObjects.push_back("happy");
+        rightObjects.push_back("smart");
+
+        kb->addFacts("is", leftObjects, rightObjects);*/
+    }
+    catch (obelisk::KnowledgeBaseException& exception)
+    {
+        std::cout << exception.what() << std::endl;
+        return EXIT_FAILURE;
+    }
+
+    // This can be used to store a double as 2 floats in the database, then restore it back to a double.
+    // Inspired by Godot's double precision on the GPU to render large worlds.
+    /*float first;
+    float second;
+    double var = 0.123456789012345;
+    kb->getFloat(&first, &second, var);
+    std::cout << std::setprecision(std::numeric_limits<double>::digits10)
+              << "Double: " << var << std::endl
+              << "First: " << first << std::endl
+              << "Second: " << second << std::endl;
+    var = 0.0;
+    kb->getDouble(&var, first, second);
+    std::cout << std::setprecision(std::numeric_limits<double>::digits10)
+              << "Double: " << var << std::endl
+              << "First: " << first << std::endl
+              << "Second: " << second << std::endl;*/
+
     mainLoop();
 
     return EXIT_SUCCESS;