fix(CLI): request value parsing compiles and inits

Therefore, you can now actually make the call and the program will not
crash due to uninitialized Options.

Fixes #64

src/mako/cli/lib/engine.mako

@@ -1,7 +1,7 @@
 <%namespace name="util" file="../../lib/util.mako"/>\
 <%!
     from util import (hub_type, mangle_ident, indent_all_but_first_by, activity_rust_type, setter_fn_name, ADD_PARAM_FN,
-                      upload_action_fn, is_schema_with_optionals, schema_markers)
+                      upload_action_fn, is_schema_with_optionals, schema_markers, indent_by)
     from cli import (mangle_subcommand, new_method_context, PARAM_FLAG, STRUCT_FLAG, UPLOAD_FLAG, OUTPUT_FLAG, VALUE_ARG,
                      CONFIG_DIR, SCOPE_FLAG, is_request_value_property, FIELD_SEP, docopt_mode, FILE_ARG, MIME_ARG, OUT_ARG, 
                      cmd_ident, call_method_ident, arg_ident, POD_TYPES, flag_ident, ident, JSON_TYPE_VALUE_MAP,
@@ -148,6 +148,8 @@ self.opt.${cmd_ident(method)} {
     handle_props = optional_props or parameters is not UNDEFINED
     if mc.request_value:
         request_cli_schema = to_cli_schema(c, mc.request_value)
+
+    request_prop_type = None
 %>\
     ## REQUIRED PARAMETERS
 % for p in mc.required_props:
@@ -157,6 +159,7 @@ self.opt.${cmd_ident(method)} {
     opt_ident = to_opt_arg_ident(p)
 %>\
     % if is_request_value_property(mc, p):
+    <% request_prop_type = prop_type %>\
 let mut ${prop_name}: api::${prop_type} = Default::default();
     % elif p.type != 'string':
 let ${prop_name}: ${prop_type} = arg_from_str(&${opt_ident}, err, "<${mangle_subcommand(p.name)}>", "${p.type}");
@@ -240,27 +243,48 @@ ${value_unwrap}\
 <%
     allow_optionals_fn = lambda s: is_schema_with_optionals(schema_markers(s, c, transitive=False))
 
-    def flatten_schema_fields(schema, res, cur=list()):
+    def flatten_schema_fields(schema, res, init_fn_map, cur=list(), init_call=None):
         if len(cur) == 0:
+            init_call = ''
             cur = list()
 
         opt_access = '.as_mut().unwrap()'
-        if not allow_optionals_fn(schema):
+        allow_optionals = allow_optionals_fn(schema)
+        parent_init_call = init_call
+        if not allow_optionals:
             opt_access = ''
         for fn, f in schema.fields.iteritems():
-
             cur.append(['%s%s' % (mangle_ident(fn), opt_access), fn])
             if isinstance(f, SchemaEntry):
                 cur[-1][0] = mangle_ident(fn)
-                res.append((schema, f, list(cur)))
+                res.append((init_call, schema, f, list(cur)))
             else:
-                flatten_schema_fields(f, res, cur)
+                if allow_optionals:
+                    init_fn_name = 'request_%s_init' % '_'.join(mangle_ident(t[1]) for t in cur)
+                    init_call = init_fn_name + '(&mut request);'
+                    struct_field = 'request.' + '.'.join('%s%s' % (mangle_ident(t[1]), opt_access) for t in cur[:-1])
+                    if len(cur) > 1:
+                        struct_field += '.'
+                    struct_field += mangle_ident(cur[-1][1])
+                    init_fn =  "fn %s(request: &mut api::%s) {\n" % (init_fn_name, request_prop_type)
+                    if parent_init_call:
+                        pcall = parent_init_call[:parent_init_call.index('(')] + "(request)"
+                        init_fn += "    %s;\n" % pcall
+                    init_fn += "    if %s.is_none() {\n" % struct_field
+                    init_fn += "        %s = Some(Default::default());\n" % struct_field
+                    init_fn += "    }\n"
+                    init_fn += "}\n"
+                               
+                    init_fn_map[init_fn_name] = init_fn
+                # end handle init
+                flatten_schema_fields(f, res, init_fn_map, cur, init_call)
             cur.pop()
         # endfor
     # end utility
 
     schema_fields = list()
-    flatten_schema_fields(request_cli_schema, schema_fields)
+    init_fn_map = dict()
+    flatten_schema_fields(request_cli_schema, schema_fields, init_fn_map)
 %>\
 let mut field_name: FieldCursor = Default::default();
 for kvarg in ${SOPT + arg_ident(KEY_VALUE_ARG)}.iter() {
@@ -268,8 +292,11 @@ for kvarg in ${SOPT + arg_ident(KEY_VALUE_ARG)}.iter() {
     if let Err(field_err) = field_name.set(&*key) {
         err.issues.push(field_err);
     }
+    % for name in sorted(init_fn_map.keys()):
+${init_fn_map[name] | indent_by(4)}
+    % endfor
     match &field_name.to_string()[..] {
-    % for schema, fe, f in schema_fields:
+    % for init_call, schema, fe, f in schema_fields:
 <%
     # TODO: Deduplicate !
     ptype = fe.actual_property.type
@@ -281,16 +308,25 @@ for kvarg in ${SOPT + arg_ident(KEY_VALUE_ARG)}.iter() {
     allow_optionals = True
     opt_prefix = 'Some('
     opt_suffix = ')'
+    opt_access = '.as_mut().unwrap()'
     if not allow_optionals_fn(schema):
-        opt_prefix = opt_suffix = ''
+        opt_prefix = opt_suffix = opt_access = ''
 
     struct_field = 'request.' + '.'.join(t[0] for t in f)
 %>\
         "${pname}" => {
+            % if init_call:
+                ${init_call}
+            % endif
         % if fe.container_type == CTYPE_POD:
                 ${struct_field} = ${opt_prefix}\
         % else:
-                ${struct_field}.push(\
+                % if opt_prefix:
+                if ${struct_field}.is_none() {
+                    ${struct_field} = Some(Default::default());
+                }
+                % endif
+                ${struct_field}${opt_access}.push(\
         % endif
         % if ptype != 'string':
 arg_from_str(${value_unwrap}, err, "${pname}", "${ptype}")\