[feature] WFormBuilder: Skeleton for the FormBuilder's Template engine.

stdlib/web/template/template.opa

@@ -59,7 +59,7 @@
  * functions and implement parse (conversion from xml to content) and export functions.
  * {[
  * my_namespace = "http://response.xsd"
- * 
+ *
  * my_engine = { Template.empty with
  *   // Parse function. It takes the xmlns, and a xmlns parse which is able to process xmlns into Template.content.
  *   // If the current engine is able to process the current, it should create a Template.content. Otherwise, it should fail.

stdlib/widgets/formbuilder/formbuilder_template_engine.opa

@@ -0,0 +1,74 @@
+/*
+    Copyright © 2011 MLstate
+
+    This file is part of OPA.
+
+    OPA is free software: you can redistribute it and/or modify it under the
+    terms of the GNU Affero General Public License as published by the Free
+    Software Foundation, either version 3 of the License, or (at your option)
+    any later version.
+
+    OPA is distributed in the hope that it will be useful, but WITHOUT ANY
+    WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+    FOR A PARTICULAR PURPOSE.  See the GNU Affero General Public License for
+    more details.
+
+    You should have received a copy of the GNU Affero General Public License
+    along with OPA.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package widgets.formbuilder
+
+import stdlib.*
+import widgets.core
+
+/**
+ * @author Adam Koprowski
+ * @category widget
+ * @stability experimental [WIP]
+ *
+ *
+ * {1 About this module}
+ *
+ * This module defines a Template engine, allowing to easily build forms
+ * with templating machinery.
+**/
+
+type FormBuilderTemplate.tag = { form }
+
+FormBuilderTemplate =
+
+  my_ns : Uri.uri =
+    Uri.of_string("http://opalang.org/template/FormBuilder")
+    |> Option.get
+
+  FB = WFormBuilder
+
+{{
+
+  @private
+  parse(_conf, {~ns; ~tag; args=_; children=_})
+    : outcome(Template.content(either(FormBuilderTemplate.tag, 'b)), Template.failure) =
+    if ns != my_ns then
+      { failure = { namespace_not_supported_by_engine = "Got {ns}, expected {my_ns}" }}
+    else
+      match tag with
+      | "form" -> { success = Template.to_extension({form}) }
+      | _ -> { failure = { unsupported_tag; ~ns; ~tag } }
+
+  @private
+  export(content, _) =
+    match Template.from_extension(content) with
+    | {none} -> { failure = { unknown_tag = "Expected extension" } }
+    | {some=fb_tag} ->
+        match fb_tag with
+        | {form} ->
+          fields = []
+          spec = FB.create_specification(fields)
+          form = FB.create_form(spec)
+          {success = form}
+
+  engine : Template.engine =
+    { Template.empty with ~parse ~export }
+
+}}