F Error Fs0039
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Why won't my code compile? Tweet As the saying goes, “if it compiles, it's correct”, but it can be extremely frustrating just trying to get the value or constructor is not defined f# the code to compile at all! So this page is devoted to
Error Fs0010
helping you troubleshoot your F# code. I will first present some general advice on troubleshooting and some of the this expression was expected to have type unit most common errors that beginners make. After that, I will describe each of the common error messages in detail, and give examples of how they can occur and how to
F# This Value Is Not A Function And Cannot Be Applied
correct them. (Jump to the error numbers) General guidelines for troubleshooting By far the most important thing you can do is to take the time and effort to understand exactly how F# works, especially the core concepts involving functions and the type system. So please read and reread the series "thinking functionally" and "understanding F# types", play with the examples, and f# unit get comfortable with the ideas before you try to start doing serious coding. If you don’t understand how functions and types work, then the compiler errors will not make any sense. If you are coming from an imperative language such as C#, you may have developed some bad habits by relying on the debugger to find and fix incorrect code. In F#, you will probably not get that far, because the compiler is so much stricter in many ways. And of course, there is no tool to “debug” the compiler and step through its processing. The best tool for debugging compiler errors is your brain, and F# forces you to use it! Nevertheless, there are a number of extremely common errors that beginners make, and I will quickly go through them. Don’t use parentheses when calling a function In F#, whitespace is the standard separator for function parameters. You will rarely need to use parentheses, and in particular, do not use parentheses when calling a function. let add x y = x + here for a quick overview of the site Help Center Detailed answers to any questions you might have Meta Discuss the workings and policies of this site About Us Learn more about Stack Overflow the company Business Learn more about hiring developers or posting ads with us Stack Overflow Questions Jobs Documentation Tags Users Badges Ask Question x Dismiss Join the Stack Overflow Community Stack Overflow is a community of 4.7 million programmers, just like you, helping each other. Join them; it f# type only takes a minute: Sign up I got this msg while using F# query expression : error FS0039: Undefined value or constructor “query” up vote 1 down vote favorite let q = <@ seq { for i in [1..10] https://fsharpforfunandprofit.com/troubleshooting-fsharp/ do yield i } |> Seq.head @> q |> query |> ignore //error FS0039 I'am using VS2012 and F# core of "ReferenceAssemblies\Microsoft\FSharp\3.0\Runtime\v2.0\FSharp.Core.dll" (version 2.3.0.0) on .NET 3.5 ; What did I miss here? f# query-expressions share|improve this question edited Nov 1 '13 at 3:39 John Palmer 21.4k32953 asked Nov 1 '13 at 3:15 korall 253 Doing open System.Linq will fix that problem, but there is another type related error left that I am not sure about. –John Palmer http://stackoverflow.com/questions/19720207/i-got-this-msg-while-using-f-query-expression-error-fs0039-undefined-value-o Nov 1 '13 at 3:20 Thank you for your help,John Palmer.I turn the target .NET framework to .NET 4.5 and than query got it's definition.Maybe it's not available under .net 3.5 and lower? –korall Nov 1 '13 at 3:47 add a comment| 1 Answer 1 active oldest votes up vote 1 down vote accepted I might be wrong (the versioning is a bit confusing) but if you're using F# 3.0 in Visual Studio 2012, then you should be able to use the new query expression syntax instead: query { for i in 1 .. 10 do select i head } This works both in memory and for SQL databases (as well as some type providers). For more information, see the MSDN documentation. If you're using older version (or target framework), then I'd definitely recommend upgrading - the F# 3.0 queries are much more solid and easy to use. share|improve this answer answered Nov 1 '13 at 3:51 Tomas Petricek 165k9209382 You are right. Actually i thought that all features of F# 3.0 available for .NET 2.0. –korall Nov 1 '13 at 4:03 add a comment| Your Answer draft saved draft discarded Sign up or log in Sign up using Google Sign up using Facebook Sign up using Email and Password Post as a guest Name Email Post as a guest Name Email discard By posting your answer, you agree to the privacy p Sign in Pricing Blog Support Search GitHub This repository Watch 62 Star 669 Fork 418 fsharp/FAKE Code Issues https://github.com/fsharp/FAKE/issues/839 99 Pull requests 15 Projects 0 Pulse Graphs New issue https://fpish.net/topic/None/59406 Mono: error FS0039: The value or constructor 'RestoreMSSolutionPackages' is not defined #839 Closed Aaronontheweb opened this Issue Jun 23, 2015 · 2 comments Projects None yet Labels None yet Milestone No milestone Assignees No one assigned 2 participants Aaronontheweb commented is not Jun 23, 2015 Running the FAKE file included as part of Akka.NET's toolchain and I immediately run into the following issue when attempting to build on Mono (Ubuntu 14.04 LTS) using the target "all" /home/azureuser/temp/akka.net/build.fsx(65,9): error FS0039: The value or constructor 'RestoreMSSolutionPackages' is not defined What do I need to do resolve this issue f error fs0039 on Mono? The build runs fine on Windows. forki referenced this issue Jun 24, 2015 Closed WIP: Akkatest - Do not merge #840 F# Compiler and Components (Open Edition) member forki commented Jun 24, 2015 I reproduced in https://travis-ci.org/fsharp/FAKE/builds/68119473 Installing 'FAKE 3.4.1'. that's probably way to outdated. So please update your FAKE version in build.sh forki closed this Jun 24, 2015 Aaronontheweb commented Jun 24, 2015 Thanks @forki ! Aaronontheweb referenced this issue in akkadotnet/akka.net Jun 24, 2015 Merged Fixed build scripts to work around known issues with Mono 4.0 #1093 Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment Contact GitHub API Training Shop Blog About © 2016 GitHub, Inc. Terms Privacy Security Status Help You can't perform that action at this time. You signed in with another tab or window. Reload to refresh your session. You signed out in another tab or window. Reload to refresh your session. and conferences around the globeCoursesCoursesAll coursesCreate a courseSee upcoming occurrences of a course, or book a training for your companyGroupsGroups and ConferencesView allCreate a groupJoin other users around a common interestBlogsBlogsAll blog articlesWrite a blog articleRead the latest from our community membersJobsJobsView allPost a jobLand your next functional programming job or post oneDevelopersDevelopersView allFind out about fellow functional developers Back to Questions1.7kviews2commentsprint_line and read_int give error FS0039 constructor not defined f#bookIn chapter 3 of Robert Pickerings book "Foundations of F" I found the following example:let mathsPuzzle() = print_string "Enter day of the month which you were born: " let input = read_int() let x = input * 4 // Multiply it by 4 let x = x + 13 let x = x * 25 let x = x - 200 ....If I try to run it in the F# interactive console (F# 2.0 Interactive build 2.0.0.0) I get the following error: print_string "Enter day of the month which you were born: " ---^^^^^^^^^^^^ stdin(40,4): error FS0039: The value or constructor 'print_string' is not definedI can fix this with:let print_string x = printf "%s" xHowever then I get the similar error on the next line: let input = read_int() ---------------^^^^^^^^ stdin(64,16): error FS0039: The value or constructor 'read_int' is not definedHere I could not find a way to avoid the error.What do I need to do to avoid these error messages?.By Roland on 5/9/2010 9:56 AM (latest comment)Install the Powerpack: [link:fsharppowerpack.codeplex.com]Add a reference to: FSharp.PowerPack.Compatability.dllAdd to top of code: open Microsoft.FSharp.Compatibility.OCaml By brianmcn on 5/9/2010 10:09 AM (permalink)Many thanks for your help.I meantime I found the correct fsi commands for my machine:#I @"C:\Program Files\FSharpPowerPack-1.9.9.9\bin";;#r @"FSharp.PowerPack.Compatibility";;I found also an other solution:Replacing read_int withlet x = System.Console.ReadLine() |> int;;Regards RolandBy Roland on 5/9/2010 10:31 AM (permalink)Topic tagsf# × 3701websharper × 1281compiler × 272functional × 201c# × 120classes × 97web × 97ui next × 87book × 84.net × 83async × 76ui.next × 50server × 45parallel × 43parsing × 41testing × 41html × 32asynchronous × 30owin × 29monad × 28ocaml × 28tutorial × 27haskell × 26trywebsharper × 26website × 26warp × 24workflows × 22linq × 21wpf × 20fpish × 19introduction F# Functions
F# For Loop