haskell - Type inference interferes with referential transparency -

-

what precise promise/guarantee haskell language provides respect referential transparency? @ least haskell report not mention notion.

consider expression

(7^7^7`mod`5`mod`2)

and want know whether or not expression 1. safety, perform twice:

( (7^7^7`mod`5`mod`2)==1, [false,true]!!(7^7^7`mod`5`mod`2) )

which gives (true,false) ghci 7.4.1.

evidently, expression referentially opaque. how can tell whether or not program subject such behavior? can inundate program :: on not make readable. there other class of haskell programs in between miss? between annotated , unannotated one?

(apart related question found on there must else on this)

the problem overloading, indeed sort of violate referential transparency. have no idea (+) in haskell; depends on type.

when numeric type unconstrained in haskell program compiler uses type defaulting pick suitable type. convenience, , doesn't lead surprises. in case did lead surprise. in ghc can use -fwarn-type-defaults see when compiler has used defaulting pick type you. can add line default () module stop defaulting.


Comments

Post a Comment

Popular posts from this blog

java - Oracle EBS .ClassNotFoundException: oracle.apps.fnd.formsClient.FormsLauncher.class ERROR -

-
i need in configuring java on machine because, when try loading forms, loader goes in circles , gives error: java.lang.classnotfoundexception: oracle.apps.fnd.formsclient.formslauncher.class @ sun.plugin2.applet.applet2classloader.findclass(unknown source) @ sun.plugin2.applet.plugin2classloader.loadclass0(unknown source) @ sun.plugin2.applet.plugin2classloader.loadclass(unknown source) @ sun.plugin2.applet.plugin2classloader.loadclass(unknown source) @ java.lang.classloader.loadclass(unknown source) @ sun.plugin2.applet.plugin2classloader.loadcode(unknown source) @ sun.plugin2.applet.plugin2manager.createapplet(unknown source) @ sun.plugin2.applet.plugin2manager$appletexecutionrunnable.run (unknown source) @ java.lang.thread.run(unknown source) i have tried re-installing firefox, older versions of java runtime environments, disabling proxy. what missing? application working on other machines. i spent around 100 hours finding s
Read more

c# - how to use buttonedit in devexpress gridcontrol -

-
Image
i trying create gridcontrol buttonedit in 1 of columns. when user clicks button edit, popups form select product. when selection done on popup, returns datarow selection main grid below. but when column loses focus, value wrote column disappear. here code creates gridcontrol's data , buttonedit's click event. private void frmsiparisnew_load(object sender, eventargs e) { dt = new datatable(); dt.columns.add("malzeme_kodu",typeof(string)); dt.columns.add("malzeme_aciklama", typeof(string)); dt.columns.add("adet", typeof(decimal)); dt.columns.add("birim", typeof(string)); dt.columns.add("fiyat", typeof(decimal)); dt.columns.add("kur", typeof(string)); dt.columns.add("tutar", typeof(decimal)); datarow dr = dt.newrow(); dt.rows.add(dr); gc.datasource = dt; } private void repositoryitembuttoneditmal
Read more

nvd3.js - angularjs-nvd3-directives setting color in legend as well as in chart elements -

-
good morning i using angularjs-nvd3-directives, great, having difficulties when setting color of multi bar chart ( http://cmaurer.github.io/angularjs-nvd3-directives/multi.bar.chart.html ). the show legend works well: <div ng-controller="examplectrl"> <nvd3-multi-bar-chart data="exampledata" id="showlegendexample" width="550" height="300" showxaxis="true" showyaxis="true" xaxistickformat="xaxistickformatfunction()" showlegend="true"> <svg></svg> </nvd3-multi-bar-chart> </div> but when add option in conjunction color="colorfunction()" where, var colorarray = ['#ff0000', '#0000ff', '#ffff00', '#00ffff']; $scope.colorfunction = function() { return function(d, i) { return colorarray[i]; }; } the color of cha
Read more