Changes between Initial Version and Version 1 of Arrays

Timestamp:

08/19/13 14:30:22 (13 years ago)

Author:

siegel

Comment:

--

Arrays

@@ +1 @@
+= 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.