prepare/exec a statement

dummy driver that parses the query
initial type support for result_sets

src/db/db.cr

@@ -14,3 +14,5 @@ module DB
 end
 
 require "./driver"
+require "./statement"
+require "./result_set"

src/db/driver.cr

@@ -4,5 +4,7 @@ module DB
 
     def initialize(@options)
     end
+
+    abstract def prepare(query) : Statement
   end
 end

src/db/result_set.cr

@@ -0,0 +1,31 @@
+module DB
+  abstract class ResultSet
+    getter statement
+
+    def initialize(@statement : Statement)
+    end
+
+    abstract def has_next : Bool
+
+    # def read(t : T.class) : T
+    # end
+
+    # list datatypes that must be supported form the driver
+    # implementors will override read_string
+    # users will call read(String) due to overloads read(T) will be a T
+    # TODO: unable to write unions (nillables)
+    {% for t in [String, UInt64] %}
+      def read(t : {{t}}.class) : {{t}}
+        read_{{t.name.underscore}}
+      end
+
+      protected abstract def read_{{t.name.underscore}} : {{t}}
+    {% end %}
+
+    # def read(t : String.class) : String
+    #   read_string
+    # end
+    #
+    # protected abstract def read_string : String
+  end
+end

src/db/statement.cr

@@ -0,0 +1,8 @@
+module DB
+  abstract class Statement
+    def initialize(@driver)
+    end
+
+    abstract def exec(*args) : ResultSet
+  end
+end