Mercurial > urweb
diff tests/tags.ur @ 2031:d11a7a9c4a73
New syntactic shorthand for antiquoting subqueries
| author | Adam Chlipala <adam@chlipala.net> |
|---|---|
| date | Wed, 25 Jun 2014 14:04:13 -0400 |
| parents | |
| children | 884673e5f7d5 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/tests/tags.ur Wed Jun 25 14:04:13 2014 -0400 @@ -0,0 +1,23 @@ +table images : { Id : int, Content : blob } +table tags : { Id : int, Tag : string } + +datatype mode = Present | Absent +type condition = { Tag : string, Mode : mode } + +type tag_query = sql_query [] [] [] [Id = int] + +fun addCondition (c : condition) (q : tag_query) : tag_query = + case c.Mode of + Present => (SELECT I.Id AS Id + FROM ({{q}}) AS I + JOIN tags ON tags.Id = I.Id AND tags.Tag = {[c.Tag]}) + | Absent => q + +fun withConditions (cs : list condition) : tag_query = + List.foldl addCondition (SELECT images.Id AS Id FROM images) cs + +fun main (cs : list condition) : transaction page = + x <- queryX (withConditions cs) (fn r => <xml><li>{[r.Id]}</li></xml>); + return <xml><body> + {x} + </body></xml>