Ur/Web: tests/relops.ur annotate

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>

Mercurial > urweb