Cannot evaluate sizeof arrays on compiletime

[zefciu]

The size of array is known on compile time, yet nim is unable to evaluate sizeof(SomeArrayType). This limits the ability to use computations on compile time. Found this trying to compute the md5 raindbow table on compile time.

Minimal example:

type                                                                            
  SomeType = array[0..10, string]                                               
                                                                                
const some_type_size = sizeof(SomeType)

Result:

const.nim(13, 30) Error: cannot evaluate 'sizeof(SomeType)'

[markus-oberhumer]

Maybe somewhat releated, len(SomeArrayType) also does not compile.

var  v:  array[1..10, int]
type T = array[1..10, int]

var   a: int = v.sizeof
var   b: int = T.sizeof
const c: int = v.sizeof   # does not compile
const d: int = T.sizeof   # does not compile

var   e: int = v.len
var   f: int = T.len      # does not compile
const g: int = v.len
const h: int = T.len      # does not compile

[krux02]

Well I have a pull request open to make sizeof work on all types at compile time very well here:
#5664
But my checks are failing, because the packed pragma is not correctly implemented:
#5824

[markus-oberhumer]

It looks that len(SomeArrayType) has been implemented by #6032.

[mratsim]

Partially done by #8445

Primitive types will work, custom objects are pending #5664

[Araq]

This is now possible.