Import urweb_20170720+dfsg.orig.tar.gz

[dgit import orig urweb_20170720+dfsg.orig.tar.gz]

1 files changed, 34 insertions, 0 deletions

diff --git a/demo/treeFun.ur b/demo/treeFun.ur
new file mode 100644
index 0000000..2d4ef73
--- /dev/null
+++ b/demo/treeFun.ur
@@ -0,0 +1,34 @@
+functor Make(M : sig
+                 type key
+                 con id :: Name
+                 con parent :: Name
+                 con cols :: {Type}
+                 constraint [id] ~ [parent]
+                 constraint [id, parent] ~ cols
+
+                 val key_inj : sql_injectable_prim key
+
+                 table tab : ([id = key, parent = option key] ++ cols)
+             end) = struct
+
+    open M
+
+    fun tree (f : $([id = key, parent = option key] ++ cols) -> xbody)
+             (root : option M.key) =
+        let
+            fun recurse (root : option key) =
+                queryX' (SELECT * FROM tab WHERE {eqNullable' (SQL tab.{parent}) root})
+                        (fn r =>
+                            children <- recurse (Some r.Tab.id);
+                            return <xml>
+                              <li> {f r.Tab}</li>
+                              
+                              <ul>
+                                {children}
+                              </ul>
+                            </xml>)
+        in
+            recurse root
+        end
+
+end