annotate tests/relops.ur @ 1513:5616b2cbdcdb

Tutorial: hyperlinks for metaprogramming and row types
author Adam Chlipala <adam@chlipala.net>
date Wed, 20 Jul 2011 08:14:49 -0400
parents e933297c4e24
children
rev   line source
adamc@229 1 table t1 : {A : int, B : string, C : float}
adamc@229 2 table t2 : {A : float, D : int}
adamc@229 3
adamc@229 4 val q1 = (SELECT * FROM t1
adamc@229 5 UNION SELECT * FROM t1)
adamc@229 6 val q2 = (SELECT t1.A, t1.B FROM t1 WHERE t1.A = 0
adamc@229 7 INTERSECT SELECT t1.B, t1.A FROM t1 WHERE t1.B = t1.B)
adamc@229 8 val q3 = (SELECT t1.A, t1.B, t1.C FROM t1 WHERE t1.A = 0
adamc@229 9 INTERSECT SELECT * FROM t1 WHERE t1.B = 'Hello world!'
adamc@260 10 EXCEPT SELECT * FROM t1 WHERE t1.A < t1.A
adamc@260 11 UNION SELECT * FROM t1 WHERE t1.A > t1.A)
adamc@260 12
adamc@260 13 datatype list a = Nil | Cons of a * list a
adamc@260 14
adamc@260 15 val r1 : transaction (list {A : int, B : string, C : float}) =
adamc@260 16 query q3
adamc@260 17 (fn fs acc => return (Cons (fs.T1, acc)))
adamc@260 18 Nil
adamc@260 19
adamc@260 20 val r2 : transaction string =
adamc@260 21 ls <- r1;
adamc@260 22 return (case ls of
adamc@260 23 Nil => "Problem"
adamc@260 24 | Cons ({B = b, ...}, _) => b)
adamc@260 25
adamc@260 26 val main : unit -> transaction page = fn () =>
adamc@260 27 s <- r2;
adamc@1070 28 return <xml><body>
adamc@260 29 {cdata s}
adamc@1070 30 </body></xml>