nimforum mirror - c to nim: getting array elements from pointer

mantielero (orginal) [2019-10-24T13:25:42+02:00] view original

I have the following:

void setStartValues(ModelInstance *comp) {
    i(counter_) = 1;
}

where i is defined as:

#define  i(vr) comp->i[vr]

I tried to implement (naively) that in nim as:

proc setStartValues(comp:ptr ModelInstance) =
    comp.i[counter]

and I get the following error:

prueba.nim(29, 11) Error: type mismatch: got <ptr fmi2Integer, int literal(0)>
but expected one of:
template `[]`(s: string; i: int): char
first type mismatch at position: 0
proc `[]`[T, U, V](s: openArray[T]; x: HSlice[U, V]): seq[T]
first type mismatch at position: 0
proc `[]`[I: Ordinal; T](a: T; i: I): T
first type mismatch at position: 0
proc `[]`[T](s: openArray[T]; i: BackwardsIndex): T
first type mismatch at position: 0
proc `[]`[T](s: var openArray[T]; i: BackwardsIndex): var T
first type mismatch at position: 0
proc `[]`[Idx, T](a: var array[Idx, T]; i: BackwardsIndex): var T
first type mismatch at position: 0
proc `[]`[Idx, T, U, V](a: array[Idx, T]; x: HSlice[U, V]): seq[T]
first type mismatch at position: 0
proc `[]`[T, U](s: string; x: HSlice[T, U]): string
first type mismatch at position: 0
proc `[]`[Idx, T](a: array[Idx, T]; i: BackwardsIndex): T
first type mismatch at position: 0
proc `[]`(s: string; i: BackwardsIndex): char
first type mismatch at position: 0

expression: [](comp.i, 0)

What should I do?

Note: ModelInstance is defined in nim as follows (from fmuTemplate.h using nimterop):

type
  fmi2Integer* {.impfmuTemplate.} = cint
  ...
  ModelInstance* {.impfmuTemplate, bycopy.} = object
    r*: ptr fmi2Real
    i*: ptr fmi2Integer
    b*: ptr fmi2Boolean
    s*: ptr fmi2String
    isPositive*: ptr fmi2Boolean
    time*: fmi2Real
    instanceName*: fmi2String
    `type`*: fmi2Type
    GUID*: fmi2String
    functions*: ptr fmi2CallbackFunctions
    loggingOn*: fmi2Boolean
    logCategories*: array[4, fmi2Boolean]
    componentEnvironment*: fmi2ComponentEnvironment
    state*: ModelState
    eventInfo*: fmi2EventInfo
    isDirtyValues*: fmi2Boolean
    isNewEventIteration*: fmi2Boolean

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5393 :: c to nim: getting array elements from pointer