nim-typeImportC-macro

import macros

proc newWhenUseWinSdkTypedef*(name, importc, header, typ: NimNode): NimNode =
  var whenStmt = newNimNode(nnkWhenStmt)
  var useWinSdkBranch = newNimNode(nnkElifBranch)
  var useWinSdkCond = newNimNode(nnkCall)
  useWinSdkCond.add(newIdentNode(!"defined"), newIdentNode(!"useWinSdk"))
  useWinSdkBranch.add(useWinSdkCond)
  var winSdkTypeSec = newNimNode(nnkTypeSection)
  var winSdkTypeDef = newNimNode(nnkTypeDef)
  winSdkTypeDef.add(name)
  var winSdkTypePragma = newNimNode(nnkPragma)
  winSdkTypePragma.add(newColonExpr(newIdentNode(!"importC"), importc))
  winSdkTypePragma.add(newColonExpr(newIdentNode(!"header"), header))
  winSdkTypeDef.add(winSdkTypePragma)
  winSdkTypeDef.add(typ)
  winSdkTypeSec.add(winSdkTypeDef)
  useWinSdkBranch.add(winSdkTypeSec)
  whenStmt.add(useWinSdkBranch)
  var elseBranch = newNimNode(nnkElse)
  var elseTypeSec = newNimNode(nnkTypeSection)
  var elseTypeDef = newNimNode(nnkTypeDef)
  elseTypeDef.add(name, newEmptyNode(), typ)
  elseTypeSec.add(elseTypeDef)
  elseBranch.add(elseTypeSec)
  whenStmt.add(elseBranch)
  result = whenStmt
  echo repr result

proc newWhenUseWinSdkExportTypedef*(name, importc, header, typ: NimNode): NimNode =
  var exportPostfix = newNimNode(nnkPostfix)
  exportPostfix.add(newIdentNode(!"*"))
  exportPostfix.add(name)
  newWhenUseWinSdkTypedef(exportPostfix, importc, header, typ)

macro winsdkTypeDef*(name: untyped, importc, header: string, typ: untyped): typed =
  newWhenUseWinSdkTypedef(name, importc, header, typ)

macro winsdkTypeDefExp*(name: untyped, importc: string, header: string, typ: untyped): typed =
  newWhenUseWinSdkExportTypedef(name, importc, header, typ)

winsdkTypeDefExp(UlongPtr, "ULONG_PTR", "<Windows.h>", uint)

# Produces
# when defined(useWinSdk):
#   type
#     UlongPtr* {.importC: "ULONG_PTR", header: "<Windows.h>".} = uint
# else:
#   type
#     UlongPtr* = uint