Add cligen for CLI parsing + PoC license inputs

nimbusLaunch.nimble

@@ -7,7 +7,7 @@ srcDir        = "src"
 
 ### Dependencies
 
-requires "nim >= 0.18.0"
+requires "nim >= 0.18.0", "https://github.com/c-blake/cligen#head"
 
 proc test(name: string, lang: string = "cpp") =
   if not dirExists "build":

src/nimbusLaunch.nim

@@ -7,4 +7,37 @@
 #
 # at your option. This file may not be copied, modified, or distributed except according to those terms.
 
+import cligen, argcvt # argcvt is part of cligen
+import strutils
+
+type
+  License = enum
+    MIT, Apache2, GPLv2, GPLv3
+
+  Licenses = set[License]
+
+# Add Licenses support to cligen
+template argParse(dst: Licenses, key: string, val: string, help: string) =
+  let args = val.split(',')
+  dst = {}
+  for input_license in args:
+    var isValid: bool = false
+    for supported_license in low(License)..high(License):       # Interesting read: "parseEnum is slow" https://forum.nim-lang.org/t/2949
+      if cmpIgnoreStyle(input_license, $supported_license) == 0:
+        incl(dst, supported_license)
+        isValid = true
+    if not isValid:
+      argRet(1, "Wrong input license(s) for param \"$1\"\n$2" %
+             [key, help])
+
+template argHelp(helpT: seq[array[0..3, string]], defVal: Licenses,
+                  parNm: string, sh: string, parHelp: string) =
+  helpT.add([ keys(parNm, sh), "Licenses", $defVal, parHelp ])
+
+proc nimbusLaunch(licenses: Licenses = {MIT, Apache2}): int =
+  echo licenses
+  echo licenses.card # length (cardinality) of the set
+
+when isMainModule:
+  dispatch nimbusLaunch