outline of how the support for native package managers should look like

src/nimblepkg/nimscriptapi.nim

@@ -41,4 +41,59 @@ template builtin = discard
 proc getPkgDir*(): string =
   ## Returns the package directory containing the .nimble file currently
   ## being evaluated.
-  builtin
+  builtin
+
+from strutils import contains
+
+type
+  Distribution* {.pure.} = enum ## an enum so that the poor programmer
+                                ## cannot introduce typos
+    Windows, ## some version of Windows
+    Posix,   ## some Posix system
+    MacOSX,  ## some version of OSX
+    Linux,   ## some version of Linux
+    Ubuntu,
+    Gentoo,
+    Fedora,
+    RedHat,
+    BSD,
+    FreeBSD,
+    OpenBSD
+
+proc detectOsImpl(d: Distribution): bool =
+  case d
+  of Distribution.Windows: ## some version of Windows
+    result = defined(windows)
+  of Distribution.Posix: result = defined(posix)
+  of Distribution.MacOSX: result = defined(macosx)
+  of Distribution.Linux: result = defined(linux)
+  of Distribution.Ubuntu, Distribution.Gentoo, Distribution.FreeBSD,
+     Distribution.OpenBSD, Distribution.Fedora:
+    result = $d in gorge"uname"
+  of Distribution.RedHat:
+    result = "Red Hat" in gorge"uname"
+  of Distribution.BSD: result = defined(bsd)
+
+template detectOs*(d: untyped): bool =
+  detectOsImpl(Distribution.d)
+
+var foreignDeps: seq[string] = @[]
+
+proc foreignCmd*(cmd: string; requiresSudo=false) =
+  foreignDeps.add((if requiresSudo: "sudo " else: "") & cmd)
+
+proc foreignDep*(foreignPackageName: string) =
+  let p = foreignPackageName
+  when defined(windows):
+    foreignCmd "Chocolatey install " & p
+  elif defined(bsd):
+    foreignCmd "ports install " & p, true
+  elif defined(linux):
+    if detectOs(Ubuntu):
+      foreignCmd "apt-get install " & p, true
+    elif detectOs(Gentoo):
+      foreignCmd "emerge install " & p, true
+    elif detectOs(Fedora):
+      foreignCmd "yum install " & p, true
+  else:
+    discard