refactor(mbuild): new _setter method

Just to make things a little easier to read. Don't expect it to
grow much larger though.

src/mako/lib/mbuild.mako

@@ -2,7 +2,7 @@
 	from util import (put_and, rust_test_fn_invisible, rust_doc_test_norun, rust_doc_comment,
                       rb_type, mb_type, singular, hub_type, to_fqan, indent_all_but_first_by,
                       method_params, activity_rust_type, mangle_ident, activity_input_type, get_word,
-                      split_camelcase_s)
+                      split_camelcase_s, property, TREF)
 %>\
 <%namespace name="util" file="util.mako"/>\
 <%namespace name="lib" file="lib.mako"/>\
@@ -15,7 +15,6 @@
 	hub_type_name = hub_type(canonicalName)
 	m = c.fqan_map[to_fqan(name, resource, method)]
 	# an identifier for a property. We prefix them to prevent clashes with the setters
-	property = lambda x: '_' + mangle_ident(x)
 	ThisType = mb_type(resource, method) + "<'a, C, NC, A>"
 %>\
 % if 'description' in m:
@@ -51,6 +50,7 @@ pub struct ${ThisType}
            A: 'a, {
 
     hub: &'a ${hub_type_name}<C, NC, A>,
+## PROPERTIES ###############
 % for p in method_params(m):
     ${property(p.name)}: ${activity_rust_type(p)},
 % endfor
@@ -69,15 +69,40 @@ impl<'a, C, NC, A> ${ThisType} {
 
 	}
 
+## PROPERTIES ###############
 % for p in method_params(m):
+${self._setter(resource, method, m, p, ThisType, c)}\
+% endfor
+}
+</%def>
+
+
+## creates a setter for the call builder
+###############################################################################################
+###############################################################################################
+<%def name="_setter(resource, method, m, p, ThisType, c)">\
 <%
 	InType = activity_input_type(p)
+
+	def show_part_info(m, p):
+		if p.name != 'part':
+			return False
+		if not (m.get('request') and m.get('response')):
+			return False
+		return m.request.get(TREF, 'first') == m.response.get(TREF, 'second')
 %>\
 	/// Sets the *${split_camelcase_s(p.name)}* ${get_word(p, 'location')}property to the given value.
-	% if p.get('required', False):
+	///
+	% if show_part_info(m, p):
+	/// Even though the *parts* list is automatically derived from *Resource* passed in 
+	/// during instantiation and indicates which values you are passing, the response would contain the very same parts.
+	/// This may not always be desirable, as you can obtain (newly generated) parts you cannot pass in,
+	/// like statistics that are generated server side. Therefore you should use this method to specify 
+	/// the parts you provide in addition to the ones you want in the response.
+	% elif p.get('required', False):
 	/// Even though the property as already been set when instantiating this call, 
 	/// we provide this method for API completeness.
-	%endif
+	% endif
 	/// 
 	% if 'description' in p:
     ${p.description | rust_doc_comment, indent_all_but_first_by(1)}
@@ -90,7 +115,4 @@ impl<'a, C, NC, A> ${ThisType} {
 		% endif
 		return self;
 	}
-
-% endfor
-}
 </%def>

src/mako/lib/util.py

@@ -396,3 +396,7 @@ def get_word(d, n, e = ''):
     else:
         return ''
 
+# n = 'FooBar' -> _foo_bar
+def property(n):
+    return '_' + mangle_ident(n)
+