ens.nim

import compiler/[ast, idents, modulegraphs, modules, vm, vmdef], macros, ospaths, tables, threadpool

export vm

let graph* = newModuleGraph()
let identCache* = newIdentCache()

macro api*(impl: untyped): untyped =
  let moduleName = splitFile(lineInfoObj(callsite()).filename).name
  let module = graph.makeModule(moduleName)
  let ctx = newCtx(module, identCache)
  ctx.mode = emRepl
  registerAdditionalOps(ctx)

  result = newStmtList()
  let templateDef = newNimNode(nnkTemplateDef)
  
  let postfix = newNimNode(nnkPostfix)
  postfix.add(ident("*"), ident("expose"))
  
  let identDefs = newNimNode(nnkIdentDefs)
  identDefs.add(ident("procName"))
  identDefs.add(ident("procBody"))
  identDefs.add(ident("untyped"))
  identDefs.add(newEmptyNode())
  
  let formalParams = newNimNode(nnkFormalParams)
  formalParams.add(newEmptyNode(), identDefs)
  
  let dirtyPragma = newNimNode(nnkPragma)
  dirtyPragma.add(ident("dirty"))
  
  let templateBody = newStmtList()
  let cmd = newNimNode(nnkCommand)
  cmd.add(newDotExpr(ident("ctx"), ident("registerCallback")))
  
  let innerInfix = newNimNode(nnkInfix)
  innerInfix.add(ident("&"))
  innerInfix.add(ident("moduleName"))
  innerInfix.add(newStrLitNode("."))
  
  let outerInfix = newNimNode(nnkInfix)
  outerInfix.add(ident("&"), innerInfix, newCall(ident("astToStr"), ident("procName")))
  
  cmd.add(outerInfix)
  
  let lamb = newNimNode(nnkLambda)
  let lambFormalParams = newNimNode(nnkFormalParams)
  let lambIdentDefs = newNimNode(nnkIdentDefs)
  lambIdentDefs.add(ident("a"))
  lambIdentDefs.add(ident("VmArgs"))
  lambIdentDefs.add(newEmptyNode())
  lambFormalParams.add(newEmptyNode(), lambIdentDefs)
  lamb.add(newEmptyNode(), newEmptyNode(), newEmptyNode(), lambFormalParams, newEmptyNode(), newEmptyNode(), newStmtList(ident("procBody")))
  
  cmd.add(lamb)
  templateBody.add(cmd)
  
  
  templateDef.add(
    postfix, newEmptyNode(), newEmptyNode(), formalParams, dirtyPragma, newEmptyNode(), templateBody
  )

  
  result.add(templateDef)
  result.add(impl)

error.log

lib/pure/os.nim(324, 13) Error: cannot 'importc' variable at compile time
VM is only allowed to 'cast' between integers of same size

renderer.nim

import bgfxdotnim, bgfxdotnim/[platform], ens, macros, compiler/[ast, idents, modulegraphs, modules, vm, vmdef]

proc init*(pd: ptr bgfx_platform_data_t) =
  bgfx_set_platform_data(pd)

  let res = bgfx_init(BGFX_RENDERER_TYPE_COUNT, 0'u16, 0, nil, nil)
  assert res
  bgfx_reset(800, 600, 1)
  bgfx_set_debug(BGFX_DEBUG_TEXT or BGFX_DEBUG_PROFILER)

proc frame*() =
  discard bgfx_frame(false)

proc shutdown*() =
  bgfx_shutdown()

api:
  expose add:
    setResult(a, getInt(a, 0) + getInt(a, 1))

  expose sub:
    setResult(a, getInt(a, 0) - getInt(a, 1))