diff -r badbae70c51a -r cc6fd1695294 src/Pure/Tools/dotnet_setup.scala
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/Pure/Tools/dotnet_setup.scala	Sat Nov 05 22:35:20 2022 +0100
@@ -0,0 +1,185 @@
+/*  Title:      Pure/Tools/dotnet_setup.scala
+    Author:     Makarius
+
+Dynamic setup of dotnet component.
+*/
+
+package isabelle
+
+
+object Dotnet_Setup {
+  /* platforms */
+
+  sealed case class Platform_Info(
+    family: Platform.Family.Value,
+    name: String,
+    os: String = "",
+    arch: String = "x64",
+    ext: String = "sh",
+    exec: String = "bash",
+    check: () => Unit = () => ())
+
+  val all_platforms =
+    List(
+      Platform_Info(Platform.Family.linux_arm, "arm64-linux", os = "linux", arch = "arm64"),
+      Platform_Info(Platform.Family.linux, "x86_64-linux", os = "linux"),
+      Platform_Info(Platform.Family.macos, "arm64-darwin", os = "osx", arch = "arm64"),
+      Platform_Info(Platform.Family.macos, "x86_64-darwin", os = "osx"),
+      Platform_Info(Platform.Family.windows, "x86_64-windows",
+        ext = "ps1",
+        exec = "powershell -ExecutionPolicy ByPass",
+        check = () => Isabelle_System.require_command("powershell", "-NoProfile -Command Out-Null")))
+
+  def check_platform_spec(spec: String): String = {
+    val all_specs =
+      Library.distinct(all_platforms.map(_.family.toString) ::: all_platforms.map(_.name))
+    if (all_specs.contains(spec)) spec
+    else {
+      error("Bad platform specification " + quote(spec) +
+        "\n  expected " + commas_quote(all_specs))
+    }
+  }
+
+
+  /* dotnet download and setup */
+
+  def default_platform: String = Platform.Family.native(Platform.family)
+  def default_target_dir: Path = Path.explode("$ISABELLE_COMPONENTS_BASE")
+  def default_install_url: String = "https://dot.net/v1/dotnet-install"
+  def default_version: String = "6.0.402"
+
+  private val settings = """# -*- shell-script -*- :mode=shellscript:
+
+if [ -n "$ISABELLE_WINDOWS_PLATFORM64" -a -d "$COMPONENT/$ISABELLE_WINDOWS_PLATFORM64" ]; then
+  ISABELLE_DOTNET="$COMPONENT/$ISABELLE_WINDOWS_PLATFORM64/dotnet.exe"
+elif [ -n "$ISABELLE_APPLE_PLATFORM64" -a -d "$COMPONENT/$ISABELLE_APPLE_PLATFORM64" ]; then
+  ISABELLE_DOTNET="$COMPONENT/$ISABELLE_APPLE_PLATFORM64/dotnet"
+elif [ -d "$COMPONENT/$ISABELLE_PLATFORM64" ]; then
+  ISABELLE_DOTNET="$COMPONENT/$ISABELLE_PLATFORM64/dotnet"
+fi
+"""
+
+  def dotnet_setup(
+    platform_spec: String = default_platform,
+    target_dir: Path = default_target_dir,
+    install_url: String = default_install_url,
+    version: String = default_version,
+    dry_run: Boolean = false,
+    verbose: Boolean = false,
+    progress: Progress = new Progress
+  ): Unit = {
+    check_platform_spec(platform_spec)
+
+    for {
+      platform <- all_platforms
+      if platform.family.toString == platform_spec || platform.name == platform_spec
+    } {
+      progress.expose_interrupt()
+      platform.check()
+
+
+      /* component directory */
+
+      val component_dir =
+        target_dir + Path.explode(if (version.isEmpty) "dotnet-latest" else "dotnet-" + version)
+
+      if (!dry_run) {
+        val etc_dir = Isabelle_System.make_directory(component_dir + Path.explode("etc"))
+        val settings_path = etc_dir + Path.explode("settings")
+        if (!settings_path.is_file) {
+          progress.echo("Component " + component_dir.expand)
+          File.write(settings_path, settings)
+        }
+
+        File.write(component_dir + Path.explode("README"),
+          """This installation of Dotnet has been produced via "isabelle dotnet_setup".
+
+
+        Makarius
+        """ + Date.Format.date(Date.now()) + "\n")
+
+        Components.update_components(true, component_dir)
+      }
+
+
+      /* platform directory */
+
+      Isabelle_System.with_tmp_file("install", ext = platform.ext) { install =>
+        Isabelle_System.download_file(install_url + "." + platform.ext, install)
+
+        val platform_dir = component_dir + Path.explode(platform.name)
+        if (platform_dir.is_dir) {
+          progress.echo_warning("Platform " + platform.name + " already installed")
+        }
+        else {
+          progress.echo("Platform " + platform.name + " ...")
+          val script =
+            platform.exec + " " + File.bash_platform_path(install) +
+              (if (version.nonEmpty) " -Version " + Bash.string(version) else "") +
+              " -Architecture " + Bash.string(platform.arch) +
+              (if (platform.os.nonEmpty) " -OS " + Bash.string(platform.os) else "") +
+              " -InstallDir " + Bash.string(platform.name) +
+              (if (dry_run) " -DryRun" else "") +
+              " -NoPath"
+          progress.bash(script, echo = verbose,
+            cwd = if (dry_run) null else component_dir.file).check
+        }
+      }
+    }
+  }
+
+
+  /* Isabelle tool wrapper */
+
+  val isabelle_tool =
+    Isabelle_Tool("dotnet_setup", "dynamic setup of dotnet component (for Fsharp)",
+      Scala_Project.here,
+      { args =>
+
+        var target_dir = default_target_dir
+        var install_url = default_install_url
+        var version = default_version
+        var dry_run = false
+        var platforms = List(default_platform)
+        var verbose = false
+
+        val getopts = Getopts("""
+Usage: isabelle dotnet_setup [OPTIONS]
+
+  Options are:
+    -D DIR       target directory (default: """ + default_target_dir.expand + """)
+    -I URL       URL for install script without extension (default: """ + quote(default_install_url) + """)
+    -V VERSION   version (empty means "latest", default: """ + quote(default_version) + """)
+    -n           dry run: try download without installation
+    -p PLATFORMS list of platforms as family or formal name, separated by commas
+                 (default: """ + quote(default_platform) + """
+    -v           verbose
+
+  Download the Dotnet / Fsharp platform and configure it as Isabelle component.
+
+  See also:
+    https://fsharp.org
+    https://learn.microsoft.com/en-us/dotnet/core/tools/dotnet-install-script
+
+  Example:
+    isabelle dotnet_setup
+    isabelle dotnet fsi
+""",
+          "D:" -> (arg => target_dir = Path.explode(arg)),
+          "I:" -> (arg => install_url = arg),
+          "V:" -> (arg => version = arg),
+          "n" -> (_ => dry_run = true),
+          "p:" -> (arg => platforms = Library.space_explode(',', arg).map(check_platform_spec)),
+          "v" -> (_ => verbose = true))
+
+        val more_args = getopts(args)
+        if (more_args.nonEmpty) getopts.usage()
+
+        val progress = new Console_Progress()
+
+        for (platform <- platforms) {
+          dotnet_setup(platform_spec = platform, target_dir = target_dir, install_url = install_url,
+            version = version, dry_run = dry_run, verbose = verbose, progress = progress)
+        }
+      })
+}