FuncType = tuple[argTypes: seq[XfrpType], retType: XfrpType]

XfrpTypeEnv = object
  fenv: XfrpFuncTypeEnv
  venv: XfrpVarTypeEnv

proc initXfrpTypeEnv(): XfrpTypeEnv {...}{.raises: [], tags: [].}

proc addFunc(typeEnv: var XfrpTypeEnv; id: XfrpId; argTypes: seq[XfrpType];
             retType: XfrpType) {...}{.raises: [], tags: [].}

proc addVar(typeEnv: var XfrpTypeEnv; id: XfrpId; ty: XfrpType) {...}{.raises: [],
    tags: [].}

proc hasVarOrAdd(typeEnv: var XfrpTypeEnv; id: XfrpId; ty: XfrpType): bool {...}{.
    raises: [], tags: [].}

proc getFuncType(typeEnv: XfrpTypeEnv; id: XfrpId): FuncType {...}{.
    raises: [KeyError], tags: [].}

proc getVarType(typeEnv: XfrpTypeEnv; id: XfrpId): XfrpType {...}{.
    raises: [KeyError], tags: [].}

proc `$`(typeEnv: XfrpTypeEnv): string {...}{.raises: [], tags: [].}

proc xfrpTypeOf(env: XfrpTypeEnv; lit: WithCodeInfo[XfrpLiteral]): XfrpType {...}{.
    raises: [], tags: [].}

proc xfrpTypeOf(env: XfrpTypeEnv; exp: WithCodeInfo[XfrpExpr]): XfrpType {...}{.
    raises: [XfrpTypeError, KeyError], tags: [].}

proc makeTypeEnvironmentFromEnvironment(env: XfrpEnv): XfrpTypeEnv {...}{.
    raises: [KeyError, XfrpTypeError], tags: [].}