= Arrays =

Thoughts on arrays and related issues.

* drop C's silly pointer-array pun.  Pointers and arrays have nothing to do with each other.  In C,
{{{
void f(double[] x) {…}
double a[10];
…
  f(a);
…
}}}
is automatically converted to
{{{
void f(double *x) {…}
double a[10];
…
  f(&a[0]);
…
}}}
In CIVL-C (CIVL?), you write the one you mean.

* Arrays are values just like any other kind of value (similar to structs).  They can be passed as arguments to functions and returned by functions.

* The incomplete array type "array of t", denoted `t[]`, can be used (almost) anywhere a type is expected, including the element type of an array type.   The domain of `t[]` is all arrays of `t`, of any length.  A complete type `t[n]` is a subtype of `t[]`.  Example:
{{{
  $message[] append_message($message[] queue, $message m);
}}}
takes an array of messages and returns an array one longer which is equivalent to the original array with $m$ added.  There is no "sharing" between these two arrays.

* Instead of malloc, introduce an operator `$alloc(heap, type)` where `heap` is an expression of type pointer-to-heap and `type` is a type name.  The type of this expression is pointer-to-`type`.  It allocates an object of the given type on the specified heap and returns a pointer to that object.