smlpolyml

Poly/ML Exception Cast "toAddress" raised


Using Poly/ML, I wanted to write a function to construct an n*n identity matrix using Array of Arrays.

I wrote:

fun equiv x y = if x = y then 1 else 0;
fun idmatrix n = Array.tabulate(n, fn i => (Array.tabulate(n, equiv i)));

and it compiled successfully, giving

> val equiv = fn: ''a -> ''a -> int
> val idmatrix = fn: int -> int array array

But when I called idmatrix

idmatrix 2;

for a test, the output of the compiler was

> Exception- Cast "toAddress" raised

Can anybody explain why the exception was raised, please?

Thank you very much!


Solution

  • Your code works fine for me. Looking at the code that raises the exception, perhaps it's a 32/64-bit address problem? Is your Poly/ML compiled for the right architecture?

    Poly/ML:

    $ poly
    Poly/ML 5.2 Release
    > fun equiv x y = if x = y then 1 else 0;
    val equiv = fn : ''a -> ''a -> int
    > fun idmatrix n = Array.tabulate(n, fn i => (Array.tabulate(n, equiv i)));
    val idmatrix = fn : int -> int Array.array Array.array
    > idmatrix 3;
    val it = fromList[fromList[1, 0, 0], fromList[0, 1, 0], fromList[0, 0, 1]]
    : int Array.array Array.array
    

    Moscow ML:

    $ mosml
    Moscow ML version 2.10
    Enter `quit();' to quit.
    - fun equiv x y = if x = y then 1 else 0;
    > val ''a equiv = fn : ''a -> ''a -> int
    - fun idmatrix n = Array.tabulate(n, fn i => (Array.tabulate(n, equiv i)));
    > val idmatrix = fn : int -> int array array
    - idmatrix 3;
    > val it = <array> : int array array
    

    And SML/NJ:

    $ sml
    Standard ML of New Jersey v110.76 [built: Sun Jun 29 03:29:51 2014]
    - fun equiv x y = if x = y then 1 else 0;
    stdIn:1.23 Warning: calling polyEqual
    val equiv = fn : ''a -> ''a -> int
    - fun idmatrix n = Array.tabulate(n, fn i => (Array.tabulate(n, equiv i)));
    [autoloading]
    [library $SMLNJ-BASIS/basis.cm is stable]
    [autoloading done]
    val idmatrix = fn : int -> int array array
    - idmatrix 3;
    val it = [|[|1,0,0|],[|0,1,0|],[|0,0,1|]|] : int array array