use macro to generate methods

src/mechanize/form.cr

@@ -34,7 +34,13 @@ class MechanizeCr::Form
     build_query_string(query_params)
   end
 
-  def fields_with(criteria)
+  # generate fields_with and field_with methods.
+  # These methods are used for finding nodes that matches conditions.
+  # ex.) field_with(:name, "email") finds <input name="email">
+
+  {% for singular, index in ["field"] %}
+    {% plural = "#{singular.id}s" %}
+    def {{plural.id}}_with(criteria)
       value = Hash(String,String).new
       if String === criteria
         value = {"name" => criteria}
@@ -42,19 +48,20 @@ class MechanizeCr::Form
         # TODO
         # when args whose type isn't String is given
       end
-    f = fields.select do |field|
+      f = {{plural.id}}.select do |elm|
         value.all? do |k,v|
-        v === field.name
+          v === elm.name
         end
       end
       f.empty? ? nil : f
     end
 
-  def field_with(criteria)
-    f = fields_with(criteria)
-    raise ElementNotFoundError.new(:field, criteria) if f.nil?
+    def {{singular.id}}_with(criteria)
+      f = {{plural.id}}_with(criteria)
+      raise ElementNotFoundError.new(:{{singular.id}}, criteria) if f.nil?
       f.first
     end
+  {% end %}
 
   private def parse
     @fields = Array(FormContent::Field).new