[META] Build visualfsharp with dotnet cli

[enricosada]

build visualfsharp (fsharp.core, fsc, fsi) with dotnet cli and project.json.

The dotnet cli build doesnt replace fsproj atm, it's used only to compile netcore version of FSharp.Core/fsc package and dogfood F# dotnet cli support (dotnet-compile-fsc)

• convert .fsproj to project.json: (ref Use .NET cli to build visualfsharp #1000)
• migrate custom msbuild task as dotnet/cli tool
  • FsSrGen:
    • Use https://github.com/fsprojects/FsSrGen nuget in master (ref Replace lkg fssrgen with FsSrGen nuget package #962)
    • Use netcore fssrgen tool ( dotnet-fssrgen nuget package )
  • FsLexYacc:
    1. Use https://github.com/fsprojects/FsLexYacc nuget in master (ref Replace lkg fslex/fsyacc with FsLexYacc nuget package #959)
    2. Use netcore fslexyacc tools: WIP in [WIP] Support coreclr using dotnet cli fsprojects/FsLexYacc#44
• build test utils in tests/fsharpqa/testenv/src with project.json
• build netcore profile
• create Microsoft.FSharp.Core.netcore nuget package
• create Microsoft.FSharp.Compiler.netcore nuget package

Answered questions

How to declare defines per target profile

use compilationOptions under framework (ref compilationoptions docs.
That's needed to replace conditional defines in msbuild like

    <DefineConstants Condition="'$(TargetFramework)'=='coreclr'">$(DefineConstants);PREFERRED_UI_LANG</DefineConstants>

Open questions

How to generate and build fs source files

Some .fs source files need to be generated with FsSrGen and FsLexYacc.

It's possible to use the precompile script to run a tool (dotnet-fssrgen for example).
But dotnet build check if a source file (declared in the compileFiles) exists before of running precompile script, so stop build before generate the files.

Workaround: create an empty .fs file placeholder.
Long term: dotnet/cli#1475

[dsyme]

I'm closing this as it is quite old and the various chances to the .NET CLI mean that the issue description would need to be rewritten