Add on option to form needs

Closes #78

spec/form_needs_spec.cr

@@ -1,10 +1,6 @@
 require "./spec_helper"
 
-private class NeedsForm < User::BaseForm
-  needs created_by : String
-  needs nilable_value : String?
-  needs optional : String = "bar"
-
+class Needs::BaseForm < User::BaseForm
   def prepare
     setup_required_fields
   end
@@ -16,6 +12,17 @@ private class NeedsForm < User::BaseForm
   end
 end
 
+private class NeedsForm < Needs::BaseForm
+  needs created_by : String
+  needs nilable_value : String?
+  needs optional : String = "bar"
+end
+
+private class NeedsWithOnOptionForm < Needs::BaseForm
+  needs created_by : String, on: :create
+  needs updated_by : String, on: :update
+end
+
 describe "LuckyRecord::Form needs" do
   it "does not change the default initializer" do
     params = {"name" => "Paul"}
@@ -43,4 +50,19 @@ describe "LuckyRecord::Form needs" do
       form.created_by.should eq("Jane")
     end
   end
+
+  it "can have needs for just create or update" do
+    params = {"name" => "Paul"}
+    create_user
+    user = UserQuery.new.first
+
+    NeedsWithOnOptionForm.save(params, created_by: "Bob") do |form, _record|
+      form.created_by.should eq("Bob")
+      form.updated_by.should be_nil
+    end
+    NeedsWithOnOptionForm.update(user, params, updated_by: "Laura") do |form, _record|
+      form.created_by.should be_nil
+      form.updated_by.should eq("Laura")
+    end
+  end
 end

src/lucky_record/needy_initializer.cr

@@ -1,6 +1,7 @@
 module LuckyRecord::NeedyInitializer
   macro included
-    NEEDS = [] of Nil
+    NEEDS_ON_CREATE = [] of Nil
+    NEEDS_ON_UPDATE = [] of Nil
 
     macro inherited
       inherit_page_settings
@@ -10,17 +11,35 @@ module LuckyRecord::NeedyInitializer
   end
 
   macro needs(type_declaration)
-    {% NEEDS << type_declaration %}
+    needs {{ type_declaration }}, on: :update
+    needs {{ type_declaration }}, on: :create
+  end
+
+  macro needs(type_declaration, on)
+    {% if ![:create, :update].includes?(on) %}
+      {% raise "on option must be :create or :update" %}
+    {% end %}
+    {% if on == :update %}
+      {% NEEDS_ON_UPDATE << type_declaration %}
+    {% else %}
+      {% NEEDS_ON_CREATE << type_declaration %}
+    {% end %}
     @{{ type_declaration.var }} : {{ type_declaration.type }}?
     property {{ type_declaration.var }}
   end
 
   macro inherit_page_settings
-    NEEDS = [] of Nil
+    \{% if !@type.constant(:NEEDS_ON_CREATE) %}
+      NEEDS_ON_CREATE = [] of Nil
+      NEEDS_ON_UPDATE = [] of Nil
+    \{% end %}
 
     \{% if !@type.ancestors.first.abstract? %}
-      \{% for type_declaration in @type.ancestors.first.constant :NEEDS %}
-        \{% NEEDS << type_declaration %}
+      \{% for type_declaration in @type.ancestors.first.constant :NEEDS_ON_CREATE %}
+        \{% NEEDS_ON_CREATE << type_declaration %}
+      \{% end %}
+      \{% for type_declaration in @type.ancestors.first.constant :NEEDS_ON_CREATE %}
+        \{% NEEDS_ON_UPDATE << type_declaration %}
       \{% end %}
     \{% end %}
 
@@ -37,14 +56,14 @@ module LuckyRecord::NeedyInitializer
   macro generate_save_methods
     def self.save(
         params,
-        {% for type_declaration in NEEDS %}
+        {% for type_declaration in NEEDS_ON_CREATE %}
           {{ type_declaration }},
         {% end %}
       )
       form = new(
         params
       )
-      {% for type_declaration in NEEDS %}
+      {% for type_declaration in NEEDS_ON_CREATE %}
         form.{{ type_declaration.var }} = {{ type_declaration.var }}
       {% end %}
       if form.save
@@ -56,14 +75,14 @@ module LuckyRecord::NeedyInitializer
 
     def self.save!(
         params,
-        {% for type_declaration in NEEDS %}
+        {% for type_declaration in NEEDS_ON_CREATE %}
           {{ type_declaration }},
         {% end %}
       )
       form = new(
         params
       )
-      {% for type_declaration in NEEDS %}
+      {% for type_declaration in NEEDS_ON_CREATE %}
         form.{{ type_declaration.var }} = {{ type_declaration.var }}
       {% end %}
       form.save!
@@ -72,15 +91,15 @@ module LuckyRecord::NeedyInitializer
     def self.update(
         record,
         with params,
-        {% for type_declaration in NEEDS %}
+        {% for type_declaration in NEEDS_ON_UPDATE %}
           {{ type_declaration }},
         {% end %}
       )
       form = new(
         record,
         params
       )
-      {% for type_declaration in NEEDS %}
+      {% for type_declaration in NEEDS_ON_UPDATE %}
         form.{{ type_declaration.var }} = {{ type_declaration.var }}
       {% end %}
       if form.save
@@ -93,15 +112,15 @@ module LuckyRecord::NeedyInitializer
     def self.update!(
         record,
         with params,
-        {% for type_declaration in NEEDS %}
+        {% for type_declaration in NEEDS_ON_UPDATE %}
           {{ type_declaration }},
         {% end %}
       )
       form = new(
         record,
         params
       )
-      {% for type_declaration in NEEDS %}
+      {% for type_declaration in NEEDS_ON_UPDATE %}
         form.{{ type_declaration.var }} = {{ type_declaration.var }}
       {% end %}
       form.update!