Mercurial > urweb
view demo/tree.ur @ 1757:b6c4b3484752
In incremental elaboration, handle invalidated FFI signatures
author | Adam Chlipala <adam@chlipala.net> |
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date | Wed, 09 May 2012 08:53:10 -0400 |
parents | d069b193ed6b |
children |
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sequence s table t : { Id : int, Parent : option int, Nam : string } PRIMARY KEY Id, CONSTRAINT F FOREIGN KEY Parent REFERENCES t (Id) ON DELETE CASCADE open TreeFun.Make(struct con id = #Id con parent = #Parent val tab = t end) fun row r = <xml> #{[r.Id]}: {[r.Nam]} <form><submit action={del r.Id} value="Delete"/></form> <form> Add child: <textbox{#Nam}/> <submit action={add (Some r.Id)}/> </form> </xml> and main () = xml <- tree row None; return <xml><body> {xml} <form> Add a top-level node: <textbox{#Nam}/> <submit action={add None}/> </form> </body></xml> and add parent r = id <- nextval s; dml (INSERT INTO t (Id, Parent, Nam) VALUES ({[id]}, {[parent]}, {[r.Nam]})); main () and del id () = dml (DELETE FROM t WHERE Id = {[id]}); main ()