fixes #3622

compiler/pluginsupport.nim

@@ -0,0 +1,46 @@
+#
+#
+#           The Nim Compiler
+#        (c) Copyright 2015 Andreas Rumpf
+#
+#    See the file "copying.txt", included in this
+#    distribution, for details about the copyright.
+#
+
+## Plugin support for the Nim compiler. Right now they
+## need to be build with the compiler, no DLL support.
+
+import ast, semdata, idents
+
+type
+  Transformation* = proc (c: PContext; n: PNode): PNode {.nimcall.}
+  Plugin = ref object
+    fn, module, package: PIdent
+    t: Transformation
+    next: Plugin
+
+proc pluginMatches(p: Plugin; s: PSym): bool =
+  if s.name.id != p.fn.id:
+    return false
+  let module = s.skipGenericOwner
+  if module == nil or module.kind != skModule or
+      module.name.id != p.module.id:
+    return false
+  let package = module.owner
+  if package == nil or package.kind != skPackage or
+      package.name.id != p.package.id:
+    return false
+  return true
+
+var head: Plugin
+
+proc getPlugin*(fn: PSym): Transformation =
+  var it = head
+  while it != nil:
+    if pluginMatches(it, fn): return it.t
+    it = it.next
+
+proc registerPlugin*(package, module, fn: string; t: Transformation) =
+  let oldHead = head
+  head = Plugin(fn: getIdent(fn), module: getIdent(module),
+                 package: getIdent(package), t: t, next: oldHead)