提出了 Poly/ML 异常转换“toAddress”

Question

使用 Poly/ML，我想编写一个函数来使用 Array of Arrays 构造一个 n*n 单位矩阵。

我写道：

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

编译成功，给

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

但是当我调用 idmatrix

idmatrix 2;

对于一个测试，编译器的输出是

> Exception- Cast "toAddress" raised

请谁能解释一下为什么引发异常？

非常感谢！

Answer 1

您的代码对我来说很好用。看the code that raises the exception，可能是32/64位地址问题？您的 Poly/ML 是否针对正确的架构进行编译？

聚/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

莫斯科机器学习：

$ 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

和 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