generateTravisBuildEnvironments.csx

var monos = new[]{
                //"nightly",
                //"weekly",
                //"alpha",
                //"beta",
                //"latest",
                "5.14.0",
                //"5.4.0",
                //"5.2.0",
                //"5.0.1",
                //"5.0.0",
                //"4.8.0",
                //"4.6.2",
                //"4.6.1",
                //"4.6.0" ,
                ////"4.4.2",
                //"4.4.1","4.4.0","4.2.3","4.2.2","4.2.1","4.2.0","4.0.5","4.0.4.4","4.0.4","4.0.3","4.0.2","4.0.1",
                ////"4.0.0",
                ////"3.12.0",
                ////"3.10.0",
                ////"3.8.0",
                ////"3.2.8",
                ////"2.10.8"
                };

var oses = new[] { "linux",
                    "osx"//for now we lack GSL native libraries on Mac OS
                 };

var sudos = new[] {
                    "required",
                    //"false"
                };

var dists = new[] {
                    "trusty",
                    //"precise"
                  };

var dotnets = new string[] {
                        ////"1.0.0-preview2-003121",
                        ////"1.0.0-preview2-003131"
                    };

var osx_images = new[] {
    "xcode9.4",//OS X 10.13
    //"xcode8.2",//OS X 10.12
    //"xcode8.1",//OS X 10.12
    //"xcode8",//OS X 10.11
    ////"xcode7.3",//OS X 10.11
    //"xcode7.2",//OS X 10.11
    //"xcode6.4"//OS X 10.10
    };

var buildConfigs = new[] { "Release", "Debug" };

var osConfigs = new Dictionary<string, string[]>()
            {
                { "linux",dists},
                {"osx",osx_images }
            };

StringBuilder sb = new StringBuilder("matrix:" + Environment.NewLine);
sb.AppendLine("  include:");
Console.Write(sb.ToString());

foreach (var os in oses)
    foreach (var buildConfig in buildConfigs)
        foreach (var osConfig in osConfigs[os])
            foreach (var sudo in sudos)
            {
                foreach (var mono in monos)
                {
                    if (os == "linux" && (mono.StartsWith("2") || (mono.StartsWith("3") && mono[2] == '2')))
                        continue;//versions older than 3.8.0 do not support nuget on linux and we need it bad

                    if (mono == "2.10.8" && os == "osx")
                        continue;//Mono 2.10.8 is unavailable on Mac OS X

                    sb = new StringBuilder($"    - os: {os}{Environment.NewLine}");
                    if (os == "linux")
                        sb.AppendLine($"      dist: {osConfig}");
                    if (os == "osx")
                        sb.AppendLine($"      osx_image: {osConfig}");
                    sb.AppendLine($"      sudo: {sudo}");

                    sb.AppendLine($"      mono: {mono}");
                    sb.AppendLine($"      env: build_config={buildConfig}");

                    if (mono.StartsWith("2.") || mono.StartsWith("3.") || (mono.StartsWith("4.") && mono[2] < '6'))
                    {
                        sb.AppendLine($"      env: netmoniker=net40");
                        Console.Write(sb.ToString());
                    }
                    else
                    {
                        sb.AppendLine($"      env: netmoniker=net461");
                        Console.Write(sb.ToString());
                        ////sb.AppendLine($"      env: netmoniker=.NET40");
                        ////Console.Write(sb.ToString());
                    }
                }

                if (osConfig != "precise")//.NET Core does not work currently on precise dist
                    foreach (var dotnet in dotnets)
                    {

                        sb = new StringBuilder($"    - os: {os}{Environment.NewLine}");
                        if (os == "linux")
                            sb.AppendLine($"      dist: {osConfig}");
                        if (os == "osx")
                            sb.AppendLine($"      osx_image: {osConfig}");
                        sb.AppendLine($"      sudo: {sudo}");

                        sb.AppendLine($"      dotnet: {dotnet}");
                        sb.AppendLine($"      mono: none");
                        sb.AppendLine($"      env: DOTNETCORE=1");
                        sb.AppendLine($"      env: build_config={buildConfig}");
                        Console.Write(sb.ToString());
                    }
            }