Implemented 'backend' option.

babel.nim

@@ -211,8 +211,10 @@ proc buildFromDir(pkgInfo: TPackageInfo, paths: seq[string]) =
   var args = ""
   for path in paths: args.add("--path:" & path & " ")
   for bin in pkgInfo.bin:
-    echo("Building ", pkginfo.name, "/", bin, "...")
-    doCmd("nimrod c -d:release " & args & realDir / bin.changeFileExt("nim"))
+    echo("Building ", pkginfo.name, "/", bin, " using ", pkgInfo.backend,
+         " backend...")
+    doCmd("nimrod $# -d:release $#" %
+          [pkgInfo.backend, args & realDir / bin.changeFileExt("nim")])
 
 proc installFromDir(dir: string, latest: bool): string =
   ## Returns where package has been installed to.

packageinfo.nim

@@ -19,6 +19,7 @@ type
     requires*: seq[tuple[name: string, ver: PVersionRange]]
     bin*: seq[string]
     srcDir*: string
+    backend*: string
 
   TPackage* = object
     name*: string
@@ -46,6 +47,7 @@ proc initPackageInfo(): TPackageInfo =
   result.requires = @[]
   result.bin = @[]
   result.srcDir = ""
+  result.backend = "c"
 
 proc validatePackageInfo(pkgInfo: TPackageInfo, path: string) =
   if pkgInfo.name == "":
@@ -58,6 +60,8 @@ proc validatePackageInfo(pkgInfo: TPackageInfo, path: string) =
     quit("Incorrect .babel file: " & path & " does not contain a description field.")
   if pkgInfo.license == "":
     quit("Incorrect .babel file: " & path & " does not contain a license field.")
+  if pkgInfo.backend notin ["c", "cc", "objc", "cpp", "js"]:
+    raise newException(EBabel, "'" & pkgInfo.backend & "' is an invalid backend.")
 
 proc parseRequires(req: string): tuple[name: string, ver: PVersionRange] =
   try:
@@ -111,6 +115,10 @@ proc readPackageInfo*(path: string): TPackageInfo =
           of "bin":
             for i in ev.value.split(','):
               result.bin.add(i.addFileExt(ExeExt))
+          of "backend":
+            result.backend = ev.value.toLower()
+            case result.backend.normalize
+            of "javascript": result.backend = "js"
           else:
             quit("Invalid field: " & ev.key, QuitFailure)
         of "deps", "dependencies":

readme.markdown

@@ -172,6 +172,10 @@ the package after checking out the latest version.
 * ``bin`` - A list of files which should be built separated by commas with
   no file extension required. This option turns your package into a *binary
   package*, babel will build the files specified and install them appropriately.
+* ``backend`` - Specifies the backend which will be used to build the files
+  listed in ``bin``. Possible values include: ``c``, ``cc``, ``cpp``, ``objc``,
+  ``js``.
+  **Default**: c
 
 ### [Deps]/[Dependencies]