Refactor some things, per patterns learned w/ woocommerce

tailbone_corepos/templates/corepos-util.mako

@@ -1,18 +1,22 @@
 ## -*- coding: utf-8; -*-
 
+<%def name="render_xref_button()">
+  <b-button type="is-primary"
+            % if core_office_url:
+            tag="a" href="${core_office_url}" target="_blank"
+            % else:
+            disabled title="${core_office_why_no_url}"
+            % endif
+            >
+    View in CORE Office
+  </b-button>
+</%def>
+
 <%def name="render_xref_helper()">
   <div class="object-helper">
     <h3>Cross-Reference</h3>
     <div class="object-helper-content">
-      <b-button type="is-primary"
-                % if core_office_url:
-                tag="a" href="${core_office_url}" target="_blank"
-                % else:
-                disabled title="${core_office_why_no_url}"
-                % endif
-                >
-        View in CORE Office
-      </b-button>
+      ${self.render_xref_button()}
     </div>
   </div>
 </%def>

tailbone_corepos/templates/products/view.mako

@@ -1,13 +1,26 @@
 ## -*- coding: utf-8; -*-
 <%inherit file="tailbone:templates/products/view.mako" />
-<%namespace file="/corepos-util.mako" import="render_xref_helper" />
+<%namespace name="corepos" file="/corepos-util.mako" />
 
 <%def name="object_helpers()">
   ${parent.object_helpers()}
-  ${render_xref_helper()}
+  ${self.render_xref_helper()}
+</%def>
+
+<%def name="render_xref_helper()">
+  ${corepos.render_xref_helper()}
+</%def>
+
+<%def name="render_xref_button()">
+  ${corepos.render_xref_button()}
 </%def>
 
 <%def name="extra_main_fields(form)">
+  ${parent.extra_main_fields(form)}
+  ${self.extra_main_fields_corepos(form)}
+</%def>
+
+<%def name="extra_main_fields_corepos(form)">
   ${form.render_field_readonly('corepos_id')}
 </%def>