How to set path to get csc.exe on AppVeyor CI - appveyor

Question

Trying to use appveyor CI for a C++ project (Makefile) with binding in C# so I would like to be able to run csc.exe from the script line.
According to the doc https://www.appveyor.com/docs/build-environment/#net-framework, I would say csc.exe must be installed somehow in the image.
i.e. need to fill the ???????????? in my .appveyor.yml:
...
environment:
- APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
...
build:
- set PATH=C:\Python36-x64;%PATH%
- where python.exe
- where /F python.exe | tools\sed.exe -n "/\".*\"/{p;q;}" | tools\sed "s/\"//g"
- set PATH=C:\????????????;%PATH%
- where csc.exe
I got:
$ set PATH=C:\Python36-x64;%PATH%
$ where python.exe
C:\Python36-x64\python.exe
C:\Python27\python.exe
$ where /F python.exe | tools\sed.exe -n "/\".*\"/{p;q;}" | tools\sed "s/\"//g"
C:\Python36-x64\python.exe
$ where csc.exe
INFO: Could not find files for the given pattern(s).
ps: I put python as an example of what I would like to do for csc.exe, fsc.exe and dotnet ....
pps: why sed ? typically I would like a prompt equivalent to bash cmd which (i.e. only return the first one if any)

Answer 1

You can use this in appveyor.yml:
after_build:
- cmd: |
call "C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\Common7\Tools\VsDevCmd.bat"
csc.exe main.cs
The VsDevCmd.bat file will automatically set the console environment for using MS Build Tools. main.cs is for example. Also you can add cl.exe after/before with csc.exe for both C++/C# projects. See this article Developer Command Prompt for Visual Studio.

Answer 2

you can simply Recursively try to find it !
build:
- where -F -R \ csc.exe
possible output:
$ where -F -R \ csc.exe
"C:\Program Files (x86)\Microsoft ASP.NET\ASP.NET Web Stack5\Packages\Microsoft.Net.Compilers.1.0.0\tools\csc.exe"
"C:\Program Files (x86)\Microsoft SDKs\NuGetPackagesFallback\Microsoft.Net.Native.Compiler\1.7.3\tools\arm\ilc\csc\csc.exe"
"C:\Program Files (x86)\Microsoft SDKs\NuGetPackagesFallback\Microsoft.Net.Native.Compiler\1.7.3\tools\x64\ilc\csc\csc.exe"
"C:\Program Files (x86)\Microsoft SDKs\NuGetPackagesFallback\Microsoft.Net.Native.Compiler\1.7.3\tools\x86\ilc\csc\csc.exe"
"C:\Program Files (x86)\Microsoft SDKs\NuGetPackagesFallback\Microsoft.Net.Native.Compiler\2.0.2\tools\csc\csc.exe"
"C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\15.0\Bin\Roslyn\csc.exe"
then set the path accordingly...