table tab : {Id : int, Val : int, Foo : int} PRIMARY KEY Id fun cache id = res <- oneOrNoRows (SELECT A.Val FROM (tab AS A JOIN tab AS B ON A.Id = B.Id) WHERE B.Id = {[id]}); return cache {case res of None => ? | Some row => {[row.A.Val]}} (* fun cacheAlt id = *) (* res <- oneOrNoRows (SELECT Q.Id *) (* FROM (SELECT Tab.Id AS Id FROM tab WHERE Tab.Id = {[id]}) *) (* AS Q); *) (* return *) (* cacheAlt *) (* {case res of *) (* None => ? *) (* | Some row => {[row.Q.Id]}} *) (* *) (* fun sillyRecursive {Id = id : int, FooBar = fooBar} = *) (* if fooBar <= 0 *) (* then 0 *) (* else 1 + sillyRecursive {Id = id, FooBar = fooBar - 1} *) (* fun cacheR (r : {Id : int, FooBar : int}) = *) (* res <- oneOrNoRows (SELECT tab.Val *) (* FROM tab *) (* WHERE tab.Id = {[r.Id]}); *) (* return *) (* cacheR {[r.FooBar]} *) (* {case res of *) (* None => ? *) (* | Some row => {[row.Tab.Val]}} *) (* *) (* fun cache2 id v = *) (* res <- oneOrNoRows (SELECT tab.Val *) (* FROM tab *) (* WHERE tab.Id = {[id]} AND tab.Val = {[v]}); *) (* return *) (* Reading {[id]}. *) (* {case res of *) (* None => Nope, that's not it. *) (* | Some _ => Hooray! You guessed it!} *) (* *) (* fun cache2 id1 id2 = *) (* res1 <- oneOrNoRows (SELECT tab.Val *) (* FROM tab *) (* WHERE tab.Id = {[id1]}); *) (* res2 <- oneOrNoRows (SELECT tab.Val *) (* FROM tab *) (* WHERE tab.Id = {[id2]}); *) (* return *) (* Reading {[id1]} and {[id2]}. *) (* {case (res1, res2) of *) (* (Some _, Some _) => Both are there. *) (* | _ => One of them is missing.} *) (* *) fun flush id = dml (UPDATE tab SET Val = Val * (Id + 2) / Val - 3 WHERE Id = {[id]} OR Id = {[id - 1]} OR Id = {[id + 1]}); return Changed {[id]}! (* fun flash id = *) (* dml (UPDATE tab *) (* SET Foo = Val *) (* WHERE Id = {[id]} OR Id = {[id - 1]} OR Id = {[id + 1]}); *) (* return *) (* Maybe changed {[id]}? *) (* *) (* fun floosh id = *) (* dml (UPDATE tab *) (* SET Id = {[id + 1]} *) (* WHERE Id = {[id]} OR Id = {[id - 1]} OR Id = {[id + 1]}); *) (* return *) (* Shifted {[id]}! *) (* *) (* val flush17 = *) (* dml (UPDATE tab *) (* SET Val = Val * (Id + 2) / Val - 3 *) (* WHERE Id = 17); *) (* return *) (* Changed specifically 17! *) (* *) (* fun flush id = *) (* res <- oneOrNoRows (SELECT tab.Val *) (* FROM tab *) (* WHERE tab.Id = {[id]}); *) (* (case res of *) (* None => dml (INSERT INTO tab (Id, Val) *) (* VALUES ({[id]}, 0)) *) (* | Some row => dml (UPDATE tab *) (* SET Val = {[row.Tab.Val + 1]} *) (* WHERE Id = {[id]} OR Id = {[id + 1]})); *) (* return *) (* {case res of *) (* None => Initialized {[id]}! *) (* | Some row => Incremented {[id]}!} *) (* *)