Convernt question mark in instance variables

lib/structural.rb

@@ -8,6 +8,7 @@
 require 'structural/model/definer'
 require 'structural/model/descriptor'
 require 'structural/model/type_casts'
+require 'structural/model/field/ivar_name'
 require 'structural/model/field'
 require 'structural/model/association'
 require 'structural/model/has_one'

lib/structural/model/field.rb

@@ -1,9 +1,11 @@
 module Structural
   module Model
     class Field
+      include IvarName
+
       def initialize(model, name, options)
         @model = model
-        @name = name
+        @name = name.to_s
         @options = options
       end
 
@@ -34,7 +36,7 @@ def key
       end
 
       def ivar_name
-        @ivar_name ||= "@#{@name}"
+        @ivar_name ||= "@#{safe_name}"
       end
 
       def default_value

lib/structural/model/field/ivar_name.rb

@@ -0,0 +1,29 @@
+module Structural
+  module Model
+    class Field
+      module IvarName
+        def self.included(base)
+          base.extend(self)
+        end
+
+        def safe_name
+          if name_ends_with_question_mark?
+            name_without_question_mark
+          else
+            name
+          end
+        end
+
+        private
+
+        def name_ends_with_question_mark?
+          name.last == '?'
+        end
+
+        def name_without_question_mark
+          name.gsub(/\?$/, '_question_mark')
+        end
+      end
+    end
+  end
+end

lib/structural/version.rb

@@ -1,3 +1,3 @@
 module Structural
-  VERSION = '0.2.0'
+  VERSION = '0.2.1'
 end

spec/lib/structural/model/field_spec.rb

@@ -0,0 +1,34 @@
+require 'spec_helper'
+
+module Structural
+  module Model
+    describe Field do
+      subject { described_class.new(model, name, options) }
+
+      let(:model) { 'model' }
+      let(:name) { 'name' }
+      let(:options) { {} }
+
+      describe '#ivar_name' do
+        context 'when the name doesnt contain question mark' do
+          let(:ivar_name) { "@#{name}" }
+
+          it 'returns name as an instance name' do
+            expect(subject.ivar_name).to eq(ivar_name)
+          end
+        end
+      end
+
+      describe '#ivar_name' do
+        context 'when the name contains question mark' do
+          let(:name) { 'name?' }
+          let(:ivar_name) { '@name_question_mark' }
+
+          it 'returns name as an instance name' do
+            expect(subject.ivar_name).to eq(ivar_name)
+          end
+        end
+      end
+    end
+  end
+end